Merge pull request 'Let a run read from a node's pacman log never hold back a new upgrade, so the mesh can upgrade nodes at all (issue 1841)' (#454) from fix/1841-stale-run into main

Every run imported from the log ends at finished or failed and is never checked after, so the
one-run-at-a-time rule counted each as still going: novox's ask of 2026-10-22 22:00 was refused on
its install-time run 20220123T194900Z, and every node holds such runs. The rule now holds back a new
run only for a run the mesh ran whose transaction may still go on.

pacman_upgrades refused a run without its node, and the console takes node out of the arguments of
an address that names the machine, so no run could be read whole: a run without a node is now that
machine's.

.gitignore

@@ -27,3 +27,4 @@ modules/mesh-provisioner-client/cmd/mesh-provisioner-client/mesh-provisioner-cli
 modules/brother/cmd/brother/brother
 modules/mesh-build-go/cmd/mesh-build-go/mesh-build-go
 modules/mesh-config/mesh-config
+modules/mesh-build-image/cmd/mesh-build-image/mesh-build-image

checks/imagebuild/go.mod

@@ -0,0 +1,3 @@
+module git.novox.be/novox/mesh-catalog/checks/imagebuild
+
+go 1.22

checks/imagebuild/main.go

@@ -0,0 +1,92 @@
+// Command imagebuild refuses any manifest but modules/buildah providing the rootless-image-build provision
+// (novox/hq ADR 0487 §3, issue 1704): the image builder's tool is buildah alone, and docker, whose daemon holds
+// the machine's root, never stands in for it. A second provider would let a node compose mesh-build-image over
+// something that is not the rootless builder it was designed against.
+//
+//	go run . <catalogue root>
+//
+// Exits 1 on a finding.
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+	"path/filepath"
+	"sort"
+)
+
+// Provision is the provision only Provider may provide.
+const Provision = "rootless-image-build"
+
+// Provider is the one module allowed to provide it.
+const Provider = "buildah"
+
+// Finding is one manifest refused: a module other than buildah providing the provision.
+type Finding struct {
+	Module string
+}
+
+// Check reads every manifest under root/modules and answers which ones it refuses, and whether buildah provides.
+func Check(root string) ([]Finding, error) {
+	manifests, err := filepath.Glob(filepath.Join(root, "modules", "*", "module.json"))
+	if err != nil {
+		return nil, err
+	}
+	sort.Strings(manifests)
+	var out []Finding
+	provided := false
+	for _, path := range manifests {
+		raw, err := os.ReadFile(path)
+		if err != nil {
+			return nil, err
+		}
+		var m struct {
+			Module   string `json:"module"`
+			Provides []struct {
+				Name string `json:"name"`
+			} `json:"provides"`
+		}
+		if err := json.Unmarshal(raw, &m); err != nil {
+			return nil, fmt.Errorf("%s: %w", path, err)
+		}
+		for _, p := range m.Provides {
+			if p.Name != Provision {
+				continue
+			}
+			if m.Module == Provider {
+				provided = true
+			} else {
+				out = append(out, Finding{Module: m.Module})
+			}
+			break
+		}
+	}
+	if !provided {
+		out = append(out, Finding{Module: Provider})
+	}
+	return out, nil
+}
+
+func main() {
+	root := "."
+	if len(os.Args) > 1 {
+		root = os.Args[1]
+	}
+	found, err := Check(root)
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+	for _, f := range found {
+		if f.Module == Provider {
+			fmt.Printf("%s does not provide %s (novox/hq ADR 0487 §3)\n", Provider, Provision)
+			continue
+		}
+		fmt.Printf("%s provides %s: only %s may, and docker never (novox/hq ADR 0487 §3)\n", f.Module, Provision, Provider)
+	}
+	if len(found) > 0 {
+		os.Exit(1)
+	}
+	fmt.Println("imagebuild: rootless-image-build is provided only by buildah")
+}

checks/imagebuild/main_test.go

@@ -0,0 +1,74 @@
+package main
+
+import (
+	"os"
+	"path/filepath"
+	"reflect"
+	"testing"
+)
+
+func catalogue(t *testing.T, manifests map[string]string) string {
+	t.Helper()
+	root := t.TempDir()
+	for name, body := range manifests {
+		dir := filepath.Join(root, "modules", name)
+		if err := os.MkdirAll(dir, 0o755); err != nil {
+			t.Fatal(err)
+		}
+		if err := os.WriteFile(filepath.Join(dir, "module.json"), []byte(body), 0o644); err != nil {
+			t.Fatal(err)
+		}
+	}
+	return root
+}
+
+const buildah = `{"module":"buildah","provides":[{"name":"rootless-image-build","reach":"machine"}]}`
+
+func TestOnlyBuildahProvidesTheRootlessImageBuild(t *testing.T) {
+	root := catalogue(t, map[string]string{"buildah": buildah, "go": `{"module":"go","provides":[{"name":"go-toolchain"}]}`})
+	got, err := Check(root)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(got) != 0 {
+		t.Errorf("found %v, want none", got)
+	}
+}
+
+func TestDockerAndAnySecondProviderAreRefused(t *testing.T) {
+	root := catalogue(t, map[string]string{
+		"buildah": buildah,
+		"docker":  `{"module":"docker","provides":[{"name":"rootless-image-build"}]}`,
+		"other":   `{"module":"other","provides":[{"name":"x"},{"name":"rootless-image-build"}]}`,
+	})
+	got, err := Check(root)
+	if err != nil {
+		t.Fatal(err)
+	}
+	want := []Finding{{Module: "docker"}, {Module: "other"}}
+	if !reflect.DeepEqual(got, want) {
+		t.Errorf("found %v, want %v", got, want)
+	}
+}
+
+func TestBuildahMustProvideIt(t *testing.T) {
+	root := catalogue(t, map[string]string{"buildah": `{"module":"buildah"}`})
+	got, err := Check(root)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if want := []Finding{{Module: "buildah"}}; !reflect.DeepEqual(got, want) {
+		t.Errorf("found %v, want %v", got, want)
+	}
+}
+
+// The catalogue as it stands: this is the check itself, run here too.
+func TestTheCatalogueGivesTheProvisionToBuildahAlone(t *testing.T) {
+	got, err := Check("../..")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(got) != 0 {
+		t.Errorf("the catalogue's providers of rootless-image-build are wrong: %v", got)
+	}
+}

checks/imageplace/go.mod

@@ -0,0 +1,3 @@
+module git.novox.be/novox/mesh-catalog/checks/imageplace
+
+go 1.22

checks/imageplace/main.go

@@ -0,0 +1,91 @@
+// Command imageplace refuses an image artifact whose Dockerfile is not a file inside its own module's directory
+// (novox/hq ADR 0487 §1, issue 1707): the image builder builds a module from that module's directory alone, so
+// a `from` that leaves it (../other/Dockerfile) or names a file that is not there could never build.
+//
+//	go run . <catalogue root>
+//
+// Exits 1 on a finding.
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+	"path/filepath"
+	"sort"
+	"strings"
+)
+
+// Finding is one image refused: Module's artifact Artifact names From, and Why says what is wrong with it.
+type Finding struct {
+	Module, Artifact, From, Why string
+}
+
+// Check reads every manifest under root/modules and answers which images it refuses.
+func Check(root string) ([]Finding, error) {
+	manifests, err := filepath.Glob(filepath.Join(root, "modules", "*", "module.json"))
+	if err != nil {
+		return nil, err
+	}
+	sort.Strings(manifests)
+	var out []Finding
+	for _, path := range manifests {
+		raw, err := os.ReadFile(path)
+		if err != nil {
+			return nil, err
+		}
+		var m struct {
+			Module string `json:"module"`
+			Build  struct {
+				Artifacts []struct {
+					Name string `json:"name"`
+					Kind string `json:"kind"`
+					From string `json:"from"`
+				} `json:"artifacts"`
+			} `json:"build"`
+		}
+		if err := json.Unmarshal(raw, &m); err != nil {
+			return nil, fmt.Errorf("%s: %w", path, err)
+		}
+		dir := filepath.Dir(path)
+		for _, a := range m.Build.Artifacts {
+			if a.Kind != "image" {
+				continue
+			}
+			f := Finding{Module: m.Module, Artifact: a.Name, From: a.From}
+			clean := filepath.Clean(a.From)
+			switch {
+			case a.From == "" || filepath.IsAbs(clean) || clean == ".." || strings.HasPrefix(clean, ".."+string(filepath.Separator)):
+				f.Why = "is not a path inside the module's own directory"
+			default:
+				info, err := os.Stat(filepath.Join(dir, clean))
+				if err != nil || info.IsDir() {
+					f.Why = "is not a file in the module's directory"
+				}
+			}
+			if f.Why != "" {
+				out = append(out, f)
+			}
+		}
+	}
+	return out, nil
+}
+
+func main() {
+	root := "."
+	if len(os.Args) > 1 {
+		root = os.Args[1]
+	}
+	found, err := Check(root)
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+	for _, f := range found {
+		fmt.Printf("%s: image %s builds from %q, which %s (novox/hq ADR 0487 §1)\n", f.Module, f.Artifact, f.From, f.Why)
+	}
+	if len(found) > 0 {
+		os.Exit(1)
+	}
+	fmt.Println("imageplace: every image builds from a Dockerfile in its own module's directory")
+}

checks/imageplace/main_test.go

@@ -0,0 +1,84 @@
+package main
+
+import (
+	"os"
+	"path/filepath"
+	"reflect"
+	"testing"
+)
+
+// module writes modules/<name>/module.json with one image artifact from `from`, and the files named.
+func module(t *testing.T, root, name, from string, files ...string) {
+	t.Helper()
+	dir := filepath.Join(root, "modules", name)
+	if err := os.MkdirAll(dir, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	body := `{"module":"` + name + `","build":{"artifacts":[{"name":"server","kind":"image","from":"` + from + `"},{"name":"files","kind":"archive","from":"../elsewhere"}]}}`
+	if err := os.WriteFile(filepath.Join(dir, "module.json"), []byte(body), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	for _, f := range files {
+		p := filepath.Join(dir, f)
+		if err := os.MkdirAll(filepath.Dir(p), 0o755); err != nil {
+			t.Fatal(err)
+		}
+		if err := os.WriteFile(p, []byte("FROM scratch\n"), 0o644); err != nil {
+			t.Fatal(err)
+		}
+	}
+}
+
+func TestADockerfileInTheModulesOwnDirectoryPasses(t *testing.T) {
+	root := t.TempDir()
+	module(t, root, "own", "Dockerfile", "Dockerfile")
+	module(t, root, "nested", "image/Dockerfile", "image/Dockerfile")
+	got, err := Check(root)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(got) != 0 {
+		t.Errorf("found %v, want none", got)
+	}
+}
+
+func TestADockerfileOutsideTheModulesDirectoryFails(t *testing.T) {
+	root := t.TempDir()
+	module(t, root, "other", "Dockerfile", "Dockerfile")
+	module(t, root, "leaves", "../other/Dockerfile")
+	module(t, root, "absolute", "/etc/Dockerfile")
+	got, err := Check(root)
+	if err != nil {
+		t.Fatal(err)
+	}
+	var mods []string
+	for _, f := range got {
+		mods = append(mods, f.Module)
+	}
+	if want := []string{"absolute", "leaves"}; !reflect.DeepEqual(mods, want) {
+		t.Errorf("refused %v (%v), want %v", mods, got, want)
+	}
+}
+
+func TestAMissingDockerfileFails(t *testing.T) {
+	root := t.TempDir()
+	module(t, root, "gone", "Dockerfile")
+	got, err := Check(root)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(got) != 1 || got[0].Module != "gone" {
+		t.Errorf("found %v, want gone refused", got)
+	}
+}
+
+// The catalogue as it stands: this is the check itself, run here too.
+func TestTheCataloguesImagesBuildFromTheirOwnDirectories(t *testing.T) {
+	got, err := Check("../..")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(got) != 0 {
+		t.Errorf("an image builds from outside its module: %v", got)
+	}
+}

checks/owned/main.go

@@ -11,13 +11,23 @@
 //     another module, after ${dir:<id>} is resolved within each module and both homes are read as one root.
 //     Archives are not containers for this rule. This holds for ~/.ssh what checks/sshdir held (ADR 0415 §6).
 //
-//     go run . <catalogue root>
+//  5. a directory that is, lies inside or holds a directory a system package owns under /var/lib, or any other
+//     resource inside one (issue 1841: pacman's state directory, placed with "place": ".", was /var/lib/pacman, the
+//     package manager's own database directory). A placed directory is resolved as the mesh resolves it with the
+//     default data root: "." is /var/lib/<module>, "mesh" /var/lib/mesh/<module>, neither /var/lib/<module>/<id>.
+//     The system directories are checks/owned/system, captured from a machine (pacman -Qo, /usr/lib/tmpfiles.d);
+//     checks/owned/system-known names the exceptions still to fix, by module, resource and issue. That list only
+//     shrinks: an entry that no longer collides is refused, and with -base one the trunk's copy does not hold.
+//
+//     go run . [-base <trunk's system-known>] <catalogue root>
 //
 // Exits 1 on a finding.
 package main
 
 import (
 	"encoding/json"
+	"errors"
+	"flag"
 	"fmt"
 	"os"
 	"path"
@@ -27,6 +37,12 @@ import (
 	"strings"
 )
 
+// The lists of rule 5, relative to the catalogue's root.
+const (
+	SystemList  = "checks/owned/system"
+	SystemKnown = "checks/owned/system-known"
+)
+
 // Home is the one root both machine homes are read as.
 const Home = "${home}"
 
@@ -43,9 +59,9 @@ type Finding struct {
 }
 
 type resource struct {
-	ID, Type, Path, Unknown string
+	ID, Type, Path, Unknown, Place string
-	Knows                   []string
+	Knows                          []string
-	HasKnows                bool
+	HasKnows                       bool
 }
 
 type parsed struct {
@@ -65,6 +81,7 @@ func load(file string) (*parsed, error) {
 			ID      string   `json:"id"`
 			Type    string   `json:"type"`
 			Path    string   `json:"path"`
+			Place   string   `json:"place"`
 			Unknown *string  `json:"unknown"`
 			Knows   []string `json:"knows"`
 		} `json:"resources"`
@@ -81,7 +98,7 @@ func load(file string) (*parsed, error) {
 		out.Module = filepath.Base(filepath.Dir(file))
 	}
 	for _, r := range m.Resources {
-		x := resource{ID: r.ID, Type: r.Type, Path: r.Path, Knows: r.Knows, HasKnows: r.Knows != nil}
+		x := resource{ID: r.ID, Type: r.Type, Path: r.Path, Place: r.Place, Knows: r.Knows, HasKnows: r.Knows != nil}
 		if r.Unknown != nil {
 			x.Unknown = *r.Unknown
 			if x.Unknown == "" {
@@ -143,14 +160,23 @@ type declared struct {
 }
 
 // Check reads every manifest under root/modules and answers what it refuses.
-func Check(root string) ([]Finding, error) {
+func Check(root string, base []string) ([]Finding, error) {
 	files, err := filepath.Glob(filepath.Join(root, "modules", "*", "module.json"))
 	if err != nil {
 		return nil, err
 	}
 	sort.Strings(files)
+	system, err := readSystem(filepath.Join(root, SystemList))
+	if err != nil {
+		return nil, err
+	}
+	known, err := readLines(filepath.Join(root, SystemKnown))
+	if err != nil && !errors.Is(err, os.ErrNotExist) {
+		return nil, err
+	}
 	var out []Finding
 	var paths []declared
+	collided := map[string]bool{}
 	type container struct{ module, path string }
 	var containers []container
 	for _, file := range files {
@@ -170,6 +196,7 @@ func Check(root string) ([]Finding, error) {
 				dirs[r.ID] = "/placed/" + m.Module + "/" + r.ID
 			}
 		}
+		out = append(out, inSystem(m, system, known, collided)...)
 		for _, r := range m.Resources {
 			p := norm(r.Path, dirs)
 			if p != "" {
@@ -212,6 +239,28 @@ func Check(root string) ([]Finding, error) {
 			}
 		}
 	}
+	for _, k := range known {
+		if !collided[k] {
+			module, id, _ := strings.Cut(k, " ")
+			id, _, _ = strings.Cut(id, " ")
+			out = append(out, Finding{5, module, id, fmt.Sprintf("is listed in %s, and no longer lies in a system "+
+				"package's directory: take the line out, so the list only shrinks", SystemKnown)})
+		}
+	}
+	if base != nil {
+		held := map[string]bool{}
+		for _, b := range base {
+			held[b] = true
+		}
+		for _, k := range known {
+			if !held[k] {
+				module, id, _ := strings.Cut(k, " ")
+				id, _, _ = strings.Cut(id, " ")
+				out = append(out, Finding{5, module, id, fmt.Sprintf("is a new line in %s, which the trunk's copy "+
+					"does not hold: a module's directory is placed outside a system package's, never listed", SystemKnown)})
+			}
+		}
+	}
 	for _, d := range paths {
 		for _, c := range containers {
 			if c.module != d.module && (d.path == c.path || strings.HasPrefix(d.path, c.path+"/")) {
@@ -222,21 +271,140 @@ func Check(root string) ([]Finding, error) {
 	return out, nil
 }
 
-func main() {
+// systemDir is one directory a system package owns, and what says so.
-	root := "."
+type systemDir struct{ Path, Source string }
-	if len(os.Args) > 1 {
+
-		root = os.Args[1]
+// readLines is a list's lines, without comments and blank lines.
+func readLines(file string) ([]string, error) {
+	raw, err := os.ReadFile(file)
+	if err != nil {
+		return nil, err
 	}
-	found, err := Check(root)
+	var lines []string
+	for _, line := range strings.Split(string(raw), "\n") {
+		if line = strings.TrimSpace(line); line != "" && !strings.HasPrefix(line, "#") {
+			lines = append(lines, line)
+		}
+	}
+	return lines, nil
+}
+
+// readSystem is the list of system directories: "<absolute path> <package>: <how it was read>" per line. Absent or
+// empty, the check fails: a list that says nothing would let every module through.
+func readSystem(file string) ([]systemDir, error) {
+	lines, err := readLines(file)
+	if err != nil {
+		return nil, fmt.Errorf("rule 5 reads the system packages' directories from %s: %w", file, err)
+	}
+	if len(lines) == 0 {
+		return nil, fmt.Errorf("%s names no system package's directory, so rule 5 would pass everything", file)
+	}
+	var out []systemDir
+	for _, line := range lines {
+		p, source, _ := strings.Cut(line, " ")
+		if !strings.HasPrefix(p, "/var/lib/") || strings.TrimSpace(source) == "" {
+			return nil, fmt.Errorf("%s: %q is not \"/var/lib/<directory> <package>: <how it was read>\"", file, line)
+		}
+		out = append(out, systemDir{path.Clean(p), strings.TrimSpace(source)})
+	}
+	return out, nil
+}
+
+// placedAt is where the mesh places a pathless directory with the default data root (mesh-sdk catalogue dirsFor).
+func placedAt(module string, r resource) string {
+	switch r.Place {
+	case ".":
+		return "/var/lib/" + module
+	case "mesh":
+		return "/var/lib/mesh/" + module
+	}
+	return "/var/lib/" + module + "/" + r.ID
+}
+
+// inSystem is rule 5 for one module: each resource whose resolved path collides with a system package's directory,
+// unless system-known lists it (then it is marked collided, so a stale line is found).
+func inSystem(m *parsed, system []systemDir, known []string, collided map[string]bool) []Finding {
+	real := map[string]string{}
+	for _, r := range m.Resources {
+		if r.Type == "directory" && r.Path == "" && r.ID != "" {
+			real[r.ID] = placedAt(m.Module, r)
+		}
+	}
+	for _, r := range m.Resources {
+		if r.ID != "" && r.Path != "" {
+			real[r.ID] = r.Path
+		}
+	}
+	var out []Finding
+	for _, r := range m.Resources {
+		p := ""
+		if r.Path != "" {
+			p = norm(r.Path, real)
+		} else if r.Type == "directory" {
+			p = real[r.ID]
+		}
+		if !strings.HasPrefix(p, "/") {
+			continue
+		}
+		for _, s := range system {
+			inside := p == s.Path || strings.HasPrefix(p, s.Path+"/")
+			holds := r.Type == "directory" && strings.HasPrefix(s.Path, p+"/")
+			if !inside && !holds {
+				continue
+			}
+			listed := ""
+			for _, k := range known {
+				if strings.HasPrefix(k, m.Module+" "+r.ID+" ") || k == m.Module+" "+r.ID {
+					listed = k
+				}
+			}
+			if listed != "" {
+				collided[listed] = true
+				break
+			}
+			how := "is or lies inside"
+			if holds {
+				how = "holds"
+			}
+			out = append(out, Finding{5, m.Module, r.ID, fmt.Sprintf("resolves to %q, which %s %s, the directory of the "+
+				"system package %s; place it under /var/lib/mesh/%s (\"place\": \"mesh\") or a path of its own", p, how,
+				s.Path, s.Source, m.Module)})
+			break
+		}
+	}
+	return out
+}
+
+func main() {
+	baseFile := flag.String("base", "", "the trunk's copy of "+SystemKnown+": a line it does not hold is refused")
+	flag.Parse()
+	root := "."
+	if flag.NArg() > 0 {
+		root = flag.Arg(0)
+	}
+	var base []string
+	if *baseFile != "" {
+		lines, err := readLines(*baseFile)
+		if err != nil {
+			fmt.Fprintln(os.Stderr, err)
+			os.Exit(1)
+		}
+		base = append([]string{}, lines...)
+	}
+	found, err := Check(root, base)
 	if err != nil {
 		fmt.Fprintln(os.Stderr, err)
 		os.Exit(1)
 	}
 	for _, f := range found {
-		fmt.Printf("%s: %s: %s (rule %d, novox/hq ADR 0422 §8, issue 1024)\n", f.Module, f.ID, f.Why, f.Rule)
+		cite := "novox/hq ADR 0422 §8, issue 1024"
+		if f.Rule == 5 {
+			cite = "issue 1841"
+		}
+		fmt.Printf("%s: %s: %s (rule %d, %s)\n", f.Module, f.ID, f.Why, f.Rule, cite)
 	}
 	if len(found) > 0 {
 		os.Exit(1)
 	}
-	fmt.Println("owned paths: every directory and archive says how it treats unknown files; no module declares inside another's directory")
+	fmt.Println("owned paths: every directory and archive says how it treats unknown files; no module declares inside another's directory, or in a system package's")
 }

checks/owned/main_test.go

@@ -20,7 +20,10 @@ func manifest(t *testing.T, root, module, body string) {
 
 func check(t *testing.T, root string) []Finding {
 	t.Helper()
-	found, err := Check(root)
+	if _, err := os.Stat(filepath.Join(root, SystemList)); os.IsNotExist(err) {
+		lists(t, root, "/var/lib/pacman pacman: pacman -Qo\n", "")
+	}
+	found, err := Check(root, nil)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -35,6 +38,20 @@ func only(t *testing.T, found []Finding, rule int, module, id string) {
 	}
 }
 
+// lists writes the catalogue's list of system directories and its known exceptions.
+func lists(t *testing.T, root, system, known string) {
+	t.Helper()
+	if err := os.MkdirAll(filepath.Join(root, "checks", "owned"), 0o755); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(filepath.Join(root, SystemList), []byte(system), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(filepath.Join(root, SystemKnown), []byte(known), 0o644); err != nil {
+		t.Fatal(err)
+	}
+}
+
 func dir(id, path, rest string) string {
 	return `{"id":"` + id + `","type":"directory","path":"` + path + `"` + rest + `}`
 }
@@ -145,3 +162,87 @@ func TestPlacedDirectoriesOfTwoModulesAreTheirOwn(t *testing.T) {
 		t.Fatalf("refused %+v", found)
 	}
 }
+
+// 1841/AC18: a module's directory that resolves to a /var/lib directory a system package owns, lies inside one or
+// holds one, is refused, whether placed (place ".", or by default beneath the module's own) or stated; a placed
+// directory saying place "mesh" lies under /var/lib/mesh and passes (issue 1841: pacman's state was /var/lib/pacman).
+func TestADirectoryOfASystemPackageIsRefused(t *testing.T) {
+	system := "/var/lib/pacman pacman: pacman -Qo\n/var/lib/systemd/coredump systemd: tmpfiles.d/systemd.conf\n"
+	for name, resources := range map[string][]string{
+		"placed-own":     {`{"id":"state","type":"directory","place":".","unknown":"program"}`},
+		"placed-beneath": {`{"id":"coredump","type":"directory","unknown":"program"}`},
+		"stated-inside":  {dir("d", "/var/lib/pacman/keeper", `,"unknown":"program"`)},
+		"stated-holding": {dir("d", "/var/lib/systemd", `,"unknown":"program"`)},
+		"file-inside": {`{"id":"state","type":"directory","place":"mesh","unknown":"program"}`,
+			`{"id":"f","type":"file","path":"/var/lib/pacman/keeper.json"}`},
+	} {
+		module := map[string]string{"placed-own": "pacman", "placed-beneath": "systemd"}[name]
+		if module == "" {
+			module = "keeper"
+		}
+		root := t.TempDir()
+		lists(t, root, system, "")
+		manifest(t, root, module, mod(module, resources...))
+		found := check(t, root)
+		if len(found) != 1 || found[0].Rule != 5 || found[0].Module != module ||
+			!strings.Contains(found[0].Why, "/var/lib/") || !strings.Contains(found[0].Why, "package") {
+			t.Errorf("%s: found %+v; want one finding of rule 5 for %s naming the path and the package", name, found, module)
+		}
+	}
+	root := t.TempDir()
+	lists(t, root, system, "")
+	manifest(t, root, "pacman", mod("pacman",
+		`{"id":"state","type":"directory","place":"mesh","unknown":"program"}`,
+		`{"id":"f","type":"file","path":"${dir:state}/keeper.json"}`,
+		dir("other", "/var/lib/pacman-other", `,"unknown":"program"`)))
+	if found := check(t, root); len(found) != 0 {
+		t.Fatalf("a directory under /var/lib/mesh/pacman was refused: %+v", found)
+	}
+}
+
+// 1841/AC18: a known exception passes; one that no longer collides is refused, so the list only shrinks; one the trunk's
+// copy does not hold is refused; and an absent list of system directories fails the check rather than passing it.
+func TestKnownSystemExceptionsOnlyShrink(t *testing.T) {
+	system := "/var/lib/systemd systemd: tmpfiles.d/systemd.conf\n"
+	known := "# comment\nsystemd state issue 1873\n"
+	root := t.TempDir()
+	lists(t, root, system, known)
+	manifest(t, root, "systemd", mod("systemd", `{"id":"state","type":"directory","place":".","unknown":"program"}`))
+	if found := check(t, root); len(found) != 0 {
+		t.Fatalf("a known exception was refused: %+v", found)
+	}
+	if found, err := Check(root, []string{"systemd state issue 1873"}); err != nil || len(found) != 0 {
+		t.Fatalf("a known exception held by the trunk was refused: %+v %v", found, err)
+	}
+	if found, err := Check(root, []string{}); err != nil || len(found) != 1 || found[0].Rule != 5 {
+		t.Fatalf("an exception the trunk does not hold passed: %+v %v", found, err)
+	}
+
+	manifest(t, root, "systemd", mod("systemd", `{"id":"state","type":"directory","place":"mesh","unknown":"program"}`))
+	only(t, check(t, root), 5, "systemd", "state")
+
+	root = t.TempDir()
+	manifest(t, root, "a", mod("a"))
+	if err := os.MkdirAll(filepath.Join(root, "checks", "owned"), 0o755); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(filepath.Join(root, SystemList), []byte("# nothing\n"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := Check(root, nil); err == nil {
+		t.Fatal("an empty list of system directories passed")
+	}
+}
+
+// 1841/AC18: the catalogue as it stands passes rule 5 with its own lists.
+func TestTheCatalogueKeepsOutOfSystemDirectories(t *testing.T) {
+	found, err := Check("../..", nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, f := range found {
+		if f.Rule == 5 {
+			t.Errorf("%s: %s: %s", f.Module, f.ID, f.Why)
+		}
+	}
+}

checks/owned/system

@@ -0,0 +1,23 @@
+# The directories under /var/lib that a system package owns (rule 5 of checks/owned, issue 1841). A module's
+# directory, placed or stated, may not be one of these, lie inside one or hold one: the package's program and the
+# package manager keep their own files there, and the node-engine would judge, chmod or chown the directory.
+#
+# One line per directory: "<path> <package>: <how it was read>". Captured on the workstation on 2026-10-22, through
+# the mesh: pacman's own database by `pacman -Qo` (pacman_owns), the rest from the `d`, `D` and `Q` lines of
+# /usr/lib/tmpfiles.d (node-reads.search for "/var/lib/"). A directory found to belong to a package is added here.
+/var/lib/pacman pacman: pacman -Qo /var/lib/pacman/ (pacman 7.1.0)
+/var/lib/alsa alsa-utils: tmpfiles.d/alsa-utils.conf
+/var/lib/colord colord: tmpfiles.d/colord.conf
+/var/lib/containers podman: tmpfiles.d/podman.conf
+/var/lib/dbus dbus: tmpfiles.d/dbus.conf
+/var/lib/geoclue geoclue: tmpfiles.d/geoclue.conf
+/var/lib/lastlog util-linux: tmpfiles.d/lastlog2.conf
+/var/lib/libuuid util-linux: tmpfiles.d/uuidd.conf
+/var/lib/machines systemd: tmpfiles.d/systemd-nspawn.conf
+/var/lib/openvpn/chroot networkmanager-openvpn: tmpfiles.d/nm-openvpn-tmpfiles.conf
+/var/lib/portables systemd: tmpfiles.d/portables.conf
+/var/lib/postgres postgresql: tmpfiles.d/postgresql.conf
+/var/lib/private systemd: tmpfiles.d/systemd.conf
+/var/lib/rpcbind rpcbind: tmpfiles.d/rpcbind.conf
+/var/lib/systemd systemd: tmpfiles.d/systemd.conf
+/var/lib/tpm2-tss/system/keystore tpm2-tss: tmpfiles.d/tpm2-tss-fapi.conf

checks/owned/system-known

@@ -0,0 +1,5 @@
+# Modules whose directory lies in a system package's directory today (rule 5 of checks/owned, issue 1841), each with
+# the issue that moves it out: "<module> <resource id> issue <number>". This list only shrinks: a line whose module
+# no longer collides is refused, and so is a line the trunk's copy does not hold.
+postgres state issue 1873
+systemd state issue 1873

checks/particulars/covered

@@ -0,0 +1,3 @@
+# The modules the check covers (novox/hq ADR 0507 §9, issue 1838), one a line; issue 1838 widens it.
+pacman
+kernel

checks/particulars/go.mod

@@ -0,0 +1,3 @@
+module git.novox.be/novox/mesh-catalog/checks/particulars
+
+go 1.22

checks/particulars/main.go

@@ -0,0 +1,159 @@
+// Command particulars keeps this mesh's node names out of the modules it covers (novox/hq ADR 0507 §9,
+// issue 1838): a module is for any mesh, so no manifest, file, code string, identifier, comment, test name or
+// fixture of a covered module names a node of this one.
+//
+// The names are in the file `particulars` at the catalogue's root, one a line, `#` comments — the one place
+// they may be written. The modules covered are in `covered` at checks/particulars/covered, one a line. A name is matched
+// whole and in any case; a hyphen, an underscore or a CamelCase boundary parts one, so a longer word holding a name is another word.
+// The forge is not a node name: its host (git.novox.be) and the organisation path (novox/<repo>) are blanked
+// before a line is read.
+//
+//	go run . <catalogue root>
+//
+// Exits 1 naming file:line and the word, 2 when a list cannot be read.
+package main
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"regexp"
+	"sort"
+	"strings"
+)
+
+// forge is the forge's host and organisation path, blanked before a line is read; a path segment novox/ elsewhere
+// (testdata/novox/x, /srv/novox/data) is not blanked.
+var forge = regexp.MustCompile(`(?i)git\.novox\.be(?:/novox/[\w.-]+)?|(?:^|[^/\w.-])novox/[\w.-]+`)
+
+func main() {
+	root := "."
+	if len(os.Args) > 1 {
+		root = os.Args[1]
+	}
+	os.Exit(check(root))
+}
+
+// check runs the check over a catalogue and returns the exit code: 0 clean, 1 a finding, 2 a list unreadable.
+func check(root string) int {
+	names, err := readList(filepath.Join(root, "particulars"))
+	if err == nil && len(names) == 0 {
+		err = fmt.Errorf("particulars lists no name — the check would pass on anything")
+	}
+	var covered []string
+	if err == nil {
+		covered, err = readList(filepath.Join(root, "checks/particulars/covered"))
+		if err == nil && len(covered) == 0 {
+			err = fmt.Errorf("covered lists no module — the check would pass on anything")
+		}
+	}
+	if err != nil {
+		fmt.Fprintln(os.Stderr, "particulars:", err)
+		return 2
+	}
+	findings, err := run(root, names, covered)
+	if err != nil {
+		fmt.Fprintln(os.Stderr, "particulars:", err)
+		return 2
+	}
+	for _, f := range findings {
+		fmt.Println(f)
+	}
+	if len(findings) > 0 {
+		fmt.Printf("particulars: %d node name(s) in a module for any mesh (novox/hq ADR 0507 §9) — say what it shows, not where it was seen\n", len(findings))
+		return 1
+	}
+	fmt.Printf("particulars: none of %d node names in the %d covered modules\n", len(names), len(covered))
+	return 0
+}
+
+// readList reads a list: one entry a line; blank lines and lines starting with # are not entries.
+func readList(path string) ([]string, error) {
+	f, err := os.Open(path)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+	var out []string
+	sc := bufio.NewScanner(f)
+	for sc.Scan() {
+		line := strings.TrimSpace(sc.Text())
+		if line == "" || strings.HasPrefix(line, "#") {
+			continue
+		}
+		out = append(out, line)
+	}
+	return out, sc.Err()
+}
+
+// run reads every text file of each covered module and returns the findings, sorted.
+func run(root string, names, covered []string) ([]string, error) {
+	var out []string
+	for _, m := range covered {
+		dir := filepath.Join(root, "modules", m)
+		err := filepath.WalkDir(dir, func(path string, d fs.DirEntry, err error) error {
+			if err != nil {
+				return err
+			}
+			if d.IsDir() {
+				switch d.Name() {
+				case "node_modules", "dist", "vendor", ".git":
+					return filepath.SkipDir
+				}
+				return nil
+			}
+			rel, _ := filepath.Rel(root, path)
+			// A path is read too: a testdata directory named after a node is a finding.
+			for _, n := range hits(filepath.ToSlash(rel), names) {
+				out = append(out, fmt.Sprintf("%s:0: node name %q in the path", filepath.ToSlash(rel), n))
+			}
+			if d.Name() == "go.sum" {
+				return nil
+			}
+			b, err := os.ReadFile(path)
+			if err != nil {
+				return err
+			}
+			if bytes.IndexByte(b, 0) >= 0 {
+				return nil
+			}
+			out = append(out, scan(filepath.ToSlash(rel), string(b), names)...)
+			return nil
+		})
+		if err != nil {
+			return nil, err
+		}
+	}
+	sort.Strings(out)
+	return out, nil
+}
+
+// scan returns a finding for each node name in src, whole-word and in any case.
+func scan(file, src string, names []string) []string {
+	var out []string
+	for i, line := range strings.Split(src, "\n") {
+		for _, n := range hits(line, names) {
+			out = append(out, fmt.Sprintf("%s:%d: node name %q — %s", file, i+1, n, strings.Join(strings.Fields(line), " ")))
+		}
+	}
+	return out
+}
+
+// hits returns the node names one line holds: as a word (a hyphen or underscore parts it), as a part of a
+// CamelCase identifier (TestAce, novoxTree), the forge's host and organisation path blanked first.
+func hits(line string, names []string) []string {
+	line = forge.ReplaceAllStringFunc(line, func(s string) string { return strings.Repeat(" ", len(s)) })
+	var out []string
+	for _, n := range names {
+		q := regexp.QuoteMeta(n)
+		camel := regexp.QuoteMeta(strings.ToUpper(n[:1]) + n[1:])
+		rx := regexp.MustCompile(`(?i:(?:^|[^A-Za-z0-9])` + q + `(?:$|[^A-Za-z0-9]))|[a-z0-9]` + camel + `(?:$|[^a-z])|(?:^|[^A-Za-z0-9])` + q + `[A-Z0-9]`)
+		if rx.MatchString(line) {
+			out = append(out, strings.ToLower(n))
+		}
+	}
+	return out
+}

checks/particulars/main_test.go

@@ -0,0 +1,116 @@
+package main
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+var names = []string{"novox", "ace", "shanks", "g14"}
+
+func TestANodeNameIsRefusedWhereItIsWritten(t *testing.T) {
+	cases := map[string]struct{ file, src string }{
+		"manifest string": {"modules/kernel/module.json", "{\n \"description\": \"as on Shanks\"\n}\n"},
+		"file line":       {"modules/kernel/files/boot.sh", "#!/bin/sh\necho run on g14\n"},
+		"go identifier":   {"modules/kernel/cmd/x/a.go", "package main\n\nfunc novox() {}\n"},
+		"test name":       {"modules/kernel/cmd/x/a_test.go", "package main\n\nfunc TestAce(t *testing.T) {}\n\nfunc TestOnAce_x(t *testing.T) {}\n"},
+	}
+	for name, c := range cases {
+		if got := scan(c.file, c.src, names); len(got) == 0 {
+			t.Errorf("%s: %q not refused", name, c.src)
+		}
+	}
+}
+
+func TestTheFindingNamesTheLineAndTheWord(t *testing.T) {
+	got := scan("f.sh", "a\nb\nrun on ACE now\n", names)
+	if len(got) != 1 || !strings.HasPrefix(got[0], "f.sh:3:") || !strings.Contains(got[0], "ace") {
+		t.Errorf("got %v", got)
+	}
+}
+
+func TestTheForgeIsNotANodeName(t *testing.T) {
+	for _, s := range []string{
+		"see novox/hq issue 5",
+		"module git.novox.be/novox/mesh-sdk/go v1.2.3",
+		"https://git.novox.be/novox/mesh-catalog",
+		"git.novox.be",
+		"space trace surface grace g14x",
+	} {
+		if got := scan("f", s, names); len(got) != 0 {
+			t.Errorf("%q refused: %v", s, got)
+		}
+	}
+}
+
+func TestANodeNameInAPathOrJoinedIsRefused(t *testing.T) {
+	for _, s := range []string{
+		"modules/kernel/testdata/novox/meminfo",
+		"/srv/novox/data",
+		"testdata/shanks-meminfo.txt",
+		"on-shanks",
+		"shanks-desktop",
+		"mesh-novox",
+		"func novoxTree() {}",
+		"aceFiles := 1",
+		"g14Meminfo := 2",
+		"novox_tree := 3",
+	} {
+		if got := scan("f", s, names); len(got) == 0 {
+			t.Errorf("%q not refused", s)
+		}
+	}
+}
+
+func TestANodeNamedPathIsRefusedThroughRun(t *testing.T) {
+	root := t.TempDir()
+	p := filepath.Join(root, "modules/kernel/testdata/ace/x")
+	os.MkdirAll(filepath.Dir(p), 0o755)
+	os.WriteFile(p, []byte("clean\n"), 0o644)
+	got, err := run(root, names, []string{"kernel"})
+	if err != nil || len(got) != 1 || !strings.HasPrefix(got[0], "modules/kernel/testdata/ace/x:0: ") {
+		t.Errorf("got %v, %v", got, err)
+	}
+}
+
+func TestCheckReturnsOneOnAFindingAndTwoOnAnUnreadableList(t *testing.T) {
+	root := t.TempDir()
+	write := func(p, s string) {
+		p = filepath.Join(root, p)
+		os.MkdirAll(filepath.Dir(p), 0o755)
+		os.WriteFile(p, []byte(s), 0o644)
+	}
+	write("particulars", "ace\n")
+	write("checks/particulars/covered", "kernel\n")
+	write("modules/kernel/a", "clean\n")
+	if got := check(root); got != 0 {
+		t.Errorf("clean = %d, want 0", got)
+	}
+	write("modules/kernel/a", "on ace\n")
+	if got := check(root); got != 1 {
+		t.Errorf("finding = %d, want 1", got)
+	}
+	os.Remove(filepath.Join(root, "particulars"))
+	if got := check(root); got != 2 {
+		t.Errorf("no list = %d, want 2", got)
+	}
+}
+
+func TestOnlyCoveredModulesAreRead(t *testing.T) {
+	root := t.TempDir()
+	write := func(p, s string) {
+		p = filepath.Join(root, p)
+		os.MkdirAll(filepath.Dir(p), 0o755)
+		os.WriteFile(p, []byte(s), 0o644)
+	}
+	write("modules/kernel/files/a", "on novox\n")
+	write("modules/other/files/a", "on novox\n")
+	got, err := run(root, names, []string{"kernel"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(got) != 1 || !strings.Contains(got[0], "modules/kernel/files/a:1") {
+		t.Errorf("got %v", got)
+	}
+}

checks/toolchains/main.go

@@ -1,5 +1,5 @@
 // Command toolchains refuses any manifest but the owner's declaring a language's toolchain package (novox/hq
-// ADR 0477 clause 4, issue 1573): the package go only in modules/go, and nodejs and npm only in modules/nodejs.
+// ADR 0477 clause 4, issue 1573): the package go only in modules/go, nodejs and npm only in modules/nodejs, and buildah (issue 1702) only in modules/buildah.
 // Everything that compiles or runs that language requires the owner's provision instead (go-toolchain,
 // node-toolchain), so the package is declared once, and a node without the owner refuses the module that
 // needs it at resolution rather than failing at its first build. The owners must declare their packages.
@@ -19,9 +19,10 @@ import (
 
 // Owners names, for each toolchain package, the one module that declares it.
 var Owners = map[string]string{
-	"go":     "go",
+	"buildah": "buildah",
-	"nodejs": "nodejs",
+	"go":      "go",
-	"npm":    "nodejs",
+	"nodejs":  "nodejs",
+	"npm":     "nodejs",
 }
 
 // Finding is one refusal: Module declares Package, which Owner alone may, or (Missing) Owner does not declare
@@ -100,5 +101,5 @@ func main() {
 	if len(found) > 0 {
 		os.Exit(1)
 	}
-	fmt.Println("toolchains: go, nodejs and npm are declared only by their owners")
+	fmt.Println("toolchains: go, nodejs, npm and buildah are declared only by their owners")
 }

checks/toolchains/main_test.go

@@ -26,6 +26,7 @@ func TestOnlyTheOwnerDeclaresAToolchainPackage(t *testing.T) {
 	root := catalogue(t, map[string]string{
 		"go":      `{"module":"go","resources":[{"id":"go","type":"package","package":"go"}]}`,
 		"nodejs":  `{"module":"nodejs","resources":[{"id":"nodejs","type":"package","package":"nodejs"},{"id":"npm","type":"package","package":"npm"}]}`,
+		"buildah": `{"module":"buildah","resources":[{"id":"b","type":"package","package":"buildah"}]}`,
 		"lab":     `{"module":"lab","resources":[{"id":"git","type":"package","package":"git"},{"id":"go","type":"package","package":"go"}]}`,
 		"builder": `{"module":"builder","resources":[{"id":"n","type":"package","package":"nodejs"},{"id":"dir","type":"directory","path":"/go"}]}`,
 	})
@@ -39,6 +40,23 @@ func TestOnlyTheOwnerDeclaresAToolchainPackage(t *testing.T) {
 	}
 }
 
+func TestASecondDeclarerOfBuildahIsRefused(t *testing.T) {
+	root := catalogue(t, map[string]string{
+		"go":      `{"module":"go","resources":[{"id":"go","type":"package","package":"go"}]}`,
+		"nodejs":  `{"module":"nodejs","resources":[{"id":"nodejs","type":"package","package":"nodejs"},{"id":"npm","type":"package","package":"npm"}]}`,
+		"buildah": `{"module":"buildah","resources":[{"id":"b","type":"package","package":"buildah"}]}`,
+		"imagery": `{"module":"imagery","resources":[{"id":"b","type":"package","package":"buildah"}]}`,
+	})
+	got, err := Check(root)
+	if err != nil {
+		t.Fatal(err)
+	}
+	want := []Finding{{Module: "imagery", Package: "buildah", Owner: "buildah"}}
+	if !reflect.DeepEqual(got, want) {
+		t.Errorf("found %v, want %v", got, want)
+	}
+}
+
 func TestTheOwnersMustExistAndDeclareTheirPackages(t *testing.T) {
 	root := catalogue(t, map[string]string{
 		"go": `{"module":"go","resources":[]}`,
@@ -47,8 +65,8 @@ func TestTheOwnersMustExistAndDeclareTheirPackages(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	if len(got) != 3 {
+	if len(got) != 4 {
-		t.Errorf("an owner missing its packages gave %v, want three findings (go, nodejs, npm)", got)
+		t.Errorf("an owner missing its packages gave %v, want four findings (buildah, go, nodejs, npm)", got)
 	}
 }
 

health-undeclared

@@ -1,4 +1,4 @@
-59
+58
 The long-running resources of this catalogue that do not say how they are ready (`health`, novox/hq ADR 0240
 rule 8), as `module check` counts them. It may only go down: merge-check.sh fails a change that raises it, and
 one that lowers it writes the new number on the first line. From 2026-11-18, or once it is 0, a long-running

merge-check.sh

@@ -48,13 +48,23 @@
 #   10. the mail-store seat (novox/hq ADR 0378 §3, issue 800): no manifest but modules/mesh-mail claims it.
 #   11. owned paths (novox/hq ADR 0422 §8, issue 1024; it holds ~/.ssh for ssh-client as ADR 0415 §6 asked):
 #      every directory and archive says `unknown` (move-out, module or program) and a valid `knows`; `move-out`
-#      only under a home; and no module declares a path inside a directory of another module.
+#      only under a home; no module declares a path inside a directory of another module; and none is, lies in or
+#      holds a directory a system package owns under /var/lib (checks/owned/system, issue 1841).
 #      checks/sshdir (ADR 0415 §6) stays while main runs it; it goes under issue 1035 once main runs checks/owned.
+#   12. the image builder (novox/hq ADR 0487 §3, issue 1704): only modules/buildah provides rootless-image-build.
+#   13. the image's place (novox/hq ADR 0487 §1, issue 1707): every image builds from a Dockerfile in its own module's directory.
 set -eu
 
 (cd checks/words && go test -count=1 . && go run . ../..)
+# Node names (novox/hq ADR 0507 §9, issue 1838): no node name of this mesh in a covered module; the names are in
+# `particulars`, the covered modules in checks/particulars/covered.
+(cd checks/particulars && go test -count=1 . && go run . ../..)
 # The toolchains (novox/hq ADR 0477 clause 4): the package go only in modules/go, nodejs and npm only in modules/nodejs.
 (cd checks/toolchains && go test -count=1 . && go run . ../..)
+# The image builder (novox/hq ADR 0487 §3): only modules/buildah provides rootless-image-build, docker never.
+(cd checks/imagebuild && go test -count=1 . && go run . ../..)
+# The image's place (novox/hq ADR 0487 §1): every image builds from a Dockerfile in its own module's directory.
+(cd checks/imageplace && go test -count=1 . && go run . ../..)
 # The agent's home (novox/hq ADR 0266): no archive, and no file written into, under it.
 (cd checks/agenthome && go test -count=1 . && go run . ../..)
 # The mail-store seat (novox/hq ADR 0378 §3): only mesh-mail may claim it.
@@ -62,8 +72,19 @@ set -eu
 # ~/.ssh (novox/hq ADR 0415 §6): only ssh-client may name a path under it. Main's merge check runs this line, so
 # checks/sshdir stays until main runs checks/owned; it goes under issue 1035.
 (cd checks/sshdir && go test -count=1 . && go run . ../..)
-# Owned paths (novox/hq ADR 0422 §8): unknown files named per directory; no path inside another module's directory.
+# Owned paths (novox/hq ADR 0422 §8): unknown files named per directory; no path inside another module's directory;
-(cd checks/owned && go test -count=1 . && go run . ../..)
+# none in a system package's directory under /var/lib (issue 1841), the known exceptions only shrinking: judged
+# against the trunk's copy of checks/owned/system-known at the merge base; a trunk without one is the list's first copy.
+owned_base=""
+if merge_base=$(git merge-base HEAD "origin/${MESH_CHECK_BASE:-main}" 2>/dev/null); then
+	if git cat-file -e "$merge_base:checks/owned/system-known" 2>/dev/null; then
+		owned_base=$(mktemp)
+		git show "$merge_base:checks/owned/system-known" >"$owned_base"
+	fi
+else
+	echo "NOT COMPARED WITH THE TRUNK: no merge base with origin/${MESH_CHECK_BASE:-main}; checks/owned/system-known is held to the list it was first written with"
+fi
+(cd checks/owned && go test -count=1 . && if [ -n "$owned_base" ]; then go run . -base "$owned_base" ../..; else go run . ../..; fi)
 # The secrets (novox/hq issue 342): a password is not a setting, so no setting can replace the vault's. The
 # known list only shrinks: judged against the trunk's copy at the merge base, a line it does not hold is refused.
 secrets_base=""
@@ -190,6 +211,19 @@ for m in $touched; do
 	# another process) run here and nowhere else: the unit suite stays under a second (novox/hq playbook 07).
 	(cd "modules/$m" && CGO_ENABLED=$cgo GOPRIVATE=git.novox.be go vet -tags integration ${modfile:+"-modfile=$modfile"} ./... &&
 		CGO_ENABLED=$cgo GOPRIVATE=git.novox.be go test -tags integration ${modfile:+"-modfile=$modfile"} $race -count=1 ./...)
+	# The docker tests of the bus's snapshot program and entrypoint (novox/hq ADR 0480 clause 6) start throwaway nats
+	# containers, and the Go toolchain container holds no docker, so above they skip with a "NOT RUN" line. Where the
+	# build seat says docker exists (MESH_CHECK_DOCKER=1) they run here by name, and a missing docker fails the check
+	# (MESH_REQUIRE_DOCKER=1 makes the tests fail instead of skip). Without it the step says it did not run.
+	if [ "$m" = nats ]; then
+		if [ "${MESH_CHECK_DOCKER:-}" = 1 ]; then
+			(cd modules/nats && MESH_REQUIRE_DOCKER=1 CGO_ENABLED=$cgo GOPRIVATE=git.novox.be go test -tags integration ${modfile:+"-modfile=$modfile"} -count=1 \
+				-run 'TestTheDeclaredDumpRunsInTheBussImage|TestTheEntrypointReloadsTheServerWithoutDroppingAConnection|TestTheStoreSurvivesTheNewDeclarationTheOldAndTheNewAgain|TestASnapshotOfALiveBusRestoresToTheSameContent|TestTheSnapshotUserCannotChangeTheBus' \
+				./cmd/mesh-nats-snapshot) || { echo "the bus's docker tests failed"; exit 1; }
+		else
+			echo "NOT RUN: the bus's five docker tests (modules/nats/cmd/mesh-nats-snapshot) skipped: this check has no docker (MESH_CHECK_DOCKER is not 1)"
+		fi
+	fi
 done
 if [ -n "$untestable" ]; then
 	echo "the check fails: the tests of$untestable could not run (novox/hq issue 385)"

modules/buildah/README.md

@@ -0,0 +1,13 @@
+# buildah
+
+The rootless image builder as a module (novox/hq ADR 0487, issue 1702).
+
+- **The only module that declares the package `buildah`** (`checks/toolchains`), and the only one that provides
+  `rootless-image-build` (`checks/imagebuild`; docker never does).
+- **Provides `rootless-image-build` with the machine's reach**: mesh-build-image requires it, so it composes only on a
+  machine where this module is assigned, and a node without it is refused at resolution naming `buildah`.
+- **No account and no subordinate-id word.** The node-engine makes every `user` account with `useradd`, which
+  allocates the account 65536 subordinate uids and gids; mesh-build-image's own account gets its ranges that way and
+  its health proves them (it reads /etc/subuid and /etc/subgid).
+- The helpers (an OCI runtime, passt, containers-common) come as buildah's package dependencies.
+- Holds no long-running resource, so it adds nothing to `health-undeclared`.

modules/buildah/module.json

@@ -0,0 +1,21 @@
+{
+  "module": "buildah",
+  "version": "1",
+  "capabilities": [
+    "package-manager",
+    "user-namespaces"
+  ],
+  "provides": [
+    {
+      "name": "rootless-image-build",
+      "reach": "machine"
+    }
+  ],
+  "resources": [
+    {
+      "id": "buildah",
+      "type": "package",
+      "package": "buildah"
+    }
+  ]
+}

modules/disk-load/README.md

@@ -24,7 +24,7 @@ machine's resources a seat, these tools become its verbs.
 
 ## Tools
 
-All five only read.
+All six only read.
 
 | tool | what | replaces |
 |---|---|---|
@@ -32,6 +32,7 @@ All five only read.
 | `disk_top` | Over a window. `by=unit` (the default) ranks systemd units and containers by bytes moved, from their cgroups. `by=container` ranks containers by name, and `by=process` ranks processes | `iotop` |
 | `disk_filesystems` | Each filesystem that stores data, said once however many places it is mounted: size, used and free GiB, used % as `df` counts it, inodes used % | `df -h`, `df -i` |
 | `disk_devices` | Each disk without sampling: model, size, whether it spins, scheduler, queue limit, what it is built on, and since boot the GiB read and written, the busy share and the wait per read and per write | `lsblk`, `cat /proc/diskstats` |
+| `disk_folders` | Which folders fill a disk, like `du -x`: the largest folders under `path` (default `/`) to `depth` levels (default 2, at most 3), `limit` of them (default 20, at most 100), with bytes and GiB. Sizes are allocated bytes, a hard link once. It stays on the path's one filesystem: a mount below it is named, never entered. It reads every folder the tool runner can read (docker's included) and no content; folders it cannot read are counted and named. After 25 s (the tool runner gives a call 30 s) it answers what it has measured, marked `partial`, with `stopped_at` (novox/hq issue 1804) | `du -x`, `ncdu` |
 | `cpu_top` | Samples a window (`seconds`, default 3, at most 10). It answers the machine's CPU in use (% of all CPUs and as CPUs busy, from `/proc/stat`), then `by=unit` (the default) ranks systemd units and containers by CPU, from their cgroups' cpu.stat, busiest first (`limit`, default 15), with the busy time no unit accounts for; `by=container` ranks containers by name | `top`, `systemd-cgtop` |
 
 ### How each number is read
@@ -87,4 +88,5 @@ cover:
 - processes ranked, one that started inside the window left out, unreadable ones counted;
 - filesystems said once, mount escapes undone, a statfs that fails said;
 - the window's bounds;
+- folders ranked biggest first to the depth asked, a mount never entered, unreadable folders named, a walk past its bound answered as partial with where it stopped, a hard link counted once;
 - the manifest: tools listed equal tools served, all read-only, no resources, no machine named.

modules/disk-load/cmd/disk-load/folders.go

@@ -0,0 +1,197 @@
+package main
+
+import (
+	"fmt"
+	"io/fs"
+	"math"
+	"os"
+	"path/filepath"
+	"sort"
+	"strings"
+	"syscall"
+	"time"
+)
+
+// FolderBudget is how long a folder walk may take before it answers what it has measured.
+const FolderBudget = 25 * time.Second
+
+// namedUnreadable is how many unreadable folders are named; the rest are only counted.
+const namedUnreadable = 50
+
+// Folder is one folder's size: everything under it on the same filesystem.
+type Folder struct {
+	Path  string  `json:"path"`
+	Depth int     `json:"depth"`
+	Bytes int64   `json:"bytes"`
+	GiB   float64 `json:"gib"`
+}
+
+// FolderReport is the answer of disk_folders.
+type FolderReport struct {
+	Path              string   `json:"path"`
+	Bytes             int64    `json:"bytes"`
+	GiB               float64  `json:"gib"`
+	Largest           []Folder `json:"largest"`
+	Partial           bool     `json:"partial"`
+	StoppedAt         string   `json:"stopped_at,omitempty"`
+	Unreadable        int      `json:"unreadable"`
+	UnreadableFolders []string `json:"unreadable_folders,omitempty"`
+	Skipped           []string `json:"other_filesystems_skipped,omitempty"`
+	Said              []string `json:"said"`
+}
+
+func (m *Machine) readDir(real string) ([]os.DirEntry, error) {
+	if m.ReadDir != nil {
+		return m.ReadDir(real)
+	}
+	return os.ReadDir(real)
+}
+
+func (m *Machine) now() time.Time {
+	if m.Clock != nil {
+		return m.Clock()
+	}
+	return time.Now()
+}
+
+func devOf(path string, info fs.FileInfo) uint64 {
+	if st, ok := info.Sys().(*syscall.Stat_t); ok {
+		return uint64(st.Dev)
+	}
+	return 0
+}
+
+type inodeKey struct{ dev, ino uint64 }
+
+// walk is one folder measurement.
+type walk struct {
+	m        *Machine
+	maxDepth int
+	dev      uint64
+	deadline time.Time
+	seen     map[inodeKey]bool
+	folders  []Folder
+	bad      []string
+	skipped  []string
+	stopped  string
+}
+
+// Folders measures path like du -x: allocated bytes, a hard link once, never entering another filesystem.
+func (m *Machine) Folders(path string, depth, limit int) (FolderReport, error) {
+	if !filepath.IsAbs(path) {
+		return FolderReport{}, fmt.Errorf("path must be absolute, not %q", path)
+	}
+	path = filepath.Clean(path)
+	info, err := os.Stat(m.path(path))
+	if err != nil {
+		return FolderReport{}, fmt.Errorf("path %s: %w", path, err)
+	}
+	if !info.IsDir() {
+		return FolderReport{}, fmt.Errorf("path %s is not a folder", path)
+	}
+	budget := m.Budget
+	if budget == 0 {
+		budget = FolderBudget
+	}
+	w := &walk{m: m, maxDepth: depth, deadline: m.now().Add(budget), seen: map[inodeKey]bool{}}
+	w.dev = w.device(path, info)
+	total := w.dir(path, 0)
+
+	sort.SliceStable(w.folders, func(i, j int) bool {
+		if w.folders[i].Bytes != w.folders[j].Bytes {
+			return w.folders[i].Bytes > w.folders[j].Bytes
+		}
+		return w.folders[i].Path < w.folders[j].Path
+	})
+	if len(w.folders) > limit {
+		w.folders = w.folders[:limit]
+	}
+	sort.Strings(w.bad)
+	named := w.bad
+	if len(named) > namedUnreadable {
+		named = named[:namedUnreadable]
+	}
+	r := FolderReport{
+		Path: path, Bytes: total, GiB: gibOf(total), Largest: w.folders,
+		Partial: w.stopped != "", StoppedAt: w.stopped,
+		Unreadable: len(w.bad), UnreadableFolders: named, Skipped: w.skipped,
+	}
+	if r.Largest == nil {
+		r.Largest = []Folder{}
+	}
+	var said []string
+	if r.Partial {
+		said = append(said, fmt.Sprintf("PARTIAL: the walk stopped after %s at %s; sizes are what was measured so far", budget, r.StoppedAt))
+	}
+	said = append(said, fmt.Sprintf("%s holds %.1f GiB on its own filesystem", path, r.GiB))
+	if r.Unreadable > 0 {
+		said = append(said, fmt.Sprintf("%d folders could not be read (%s), so their size is missing", r.Unreadable, strings.Join(named, ", ")))
+	}
+	if len(r.Skipped) > 0 {
+		said = append(said, "other filesystems not entered: "+strings.Join(r.Skipped, ", "))
+	}
+	r.Said = said
+	return r, nil
+}
+
+func (w *walk) device(path string, info fs.FileInfo) uint64 {
+	if w.m.DevOf != nil {
+		return w.m.DevOf(path, info)
+	}
+	return devOf(path, info)
+}
+
+// dir is the allocated bytes under a folder; it records the folder when it is within the depth.
+func (w *walk) dir(path string, depth int) int64 {
+	if w.stopped != "" {
+		return 0
+	}
+	if w.m.now().After(w.deadline) {
+		w.stopped = path
+		return 0
+	}
+	entries, err := w.m.readDir(w.m.path(path))
+	if err != nil {
+		w.bad = append(w.bad, path)
+		return 0
+	}
+	var total int64
+	for _, e := range entries {
+		child := filepath.Join(path, e.Name())
+		info, err := os.Lstat(w.m.path(child))
+		if err != nil {
+			continue // gone since it was listed
+		}
+		if info.IsDir() {
+			if w.device(child, info) != w.dev {
+				w.skipped = append(w.skipped, child)
+				continue
+			}
+			total += w.allocated(info, false) + w.dir(child, depth+1)
+			continue
+		}
+		total += w.allocated(info, true)
+	}
+	if depth >= 1 && depth <= w.maxDepth {
+		w.folders = append(w.folders, Folder{Path: path, Depth: depth, Bytes: total, GiB: gibOf(total)})
+	}
+	return total
+}
+
+// allocated is the bytes an entry occupies on disk, as du counts them; a file with several links once.
+func (w *walk) allocated(info fs.FileInfo, file bool) int64 {
+	st, ok := info.Sys().(*syscall.Stat_t)
+	if !ok {
+		return info.Size()
+	}
+	if file && st.Nlink > 1 {
+		k := inodeKey{uint64(st.Dev), uint64(st.Ino)}
+		if w.seen[k] {
+			return 0
+		}
+		w.seen[k] = true
+	}
+	return st.Blocks * 512
+}
+
+func gibOf(b int64) float64 { return math.Round(float64(b)/gib*100) / 100 }

modules/disk-load/cmd/disk-load/folders_test.go

@@ -0,0 +1,170 @@
+package main
+
+import (
+	"fmt"
+	"io/fs"
+	"os"
+	"strings"
+	"testing"
+	"time"
+)
+
+const mb = 1 << 20
+
+// megabytes writes a file of n MiB under the fake root.
+func (f *fake) megabytes(path string, n int) { f.file(path, strings.Repeat("x", n*mb)) }
+
+func aFullDisk(t *testing.T) *fake {
+	f := newFake(t)
+	f.megabytes("var/lib/docker/overlay2/a/layer", 8)
+	f.megabytes("var/lib/docker/overlay2/b/layer", 4)
+	f.megabytes("var/log/big.log", 3)
+	f.megabytes("home/jo/video.mkv", 6)
+	f.megabytes("home/jo/deep/er/est/file", 1)
+	f.dir("empty")
+	return f
+}
+
+func folders(t *testing.T, m *Machine, args map[string]any) FolderReport {
+	t.Helper()
+	out, err := tool(t, m, "disk_folders").Run(args)
+	if err != nil {
+		t.Fatal(err)
+	}
+	return out.(FolderReport)
+}
+
+func paths(r FolderReport) string {
+	var p []string
+	for _, f := range r.Largest {
+		p = append(p, f.Path)
+	}
+	return strings.Join(p, ",")
+}
+
+// 1804/AC1: given a disk with folders of known sizes, when disk_folders runs with the defaults, then it answers
+// the largest folders to depth 2, biggest first, with bytes and GiB, and the total of the path.
+func TestFoldersAreRankedBiggestFirstToDepthTwoByDefault(t *testing.T) {
+	r := folders(t, aFullDisk(t).machine(), nil)
+	if got := paths(r); !strings.HasPrefix(got, "/var,/var/lib,") || !strings.Contains(got, "/home,/home/jo") {
+		t.Fatalf("ranked %s", got)
+	}
+	if r.Path != "/" || r.Partial || r.Unreadable != 0 {
+		t.Errorf("%+v", r)
+	}
+	top := r.Largest[0]
+	if top.Path != "/var" || top.Depth != 1 || top.Bytes < 15*mb || top.Bytes > 16*mb || top.GiB <= 0 {
+		t.Errorf("top %+v", top)
+	}
+	for _, f := range r.Largest {
+		if f.Depth > 2 || f.Depth < 1 {
+			t.Errorf("%+v is outside depth 2", f)
+		}
+		if strings.Contains(f.Path, "overlay2") {
+			t.Errorf("%s is deeper than 2", f.Path)
+		}
+	}
+	if r.Bytes < 22*mb || r.Bytes > 24*mb {
+		t.Errorf("total %d", r.Bytes)
+	}
+}
+
+// 1804/AC2: given a path, a depth and a limit, then only that folder is measured, depth is held at 3 and limit at 100.
+func TestFoldersTakeAPathADepthAndALimitHeldAtThreeAndAHundred(t *testing.T) {
+	f := aFullDisk(t)
+	r := folders(t, f.machine(), map[string]any{"path": "/var/lib/docker", "depth": 1.0})
+	if r.Path != "/var/lib/docker" || paths(r) != "/var/lib/docker/overlay2" {
+		t.Errorf("%s: %s", r.Path, paths(r))
+	}
+	r = folders(t, f.machine(), map[string]any{"path": "/home", "depth": 9.0, "limit": 2.0})
+	if len(r.Largest) != 2 {
+		t.Errorf("limit 2 gave %d", len(r.Largest))
+	}
+	r = folders(t, f.machine(), map[string]any{"path": "/home", "depth": 9.0})
+	if got := paths(r); !strings.Contains(got, "/home/jo/deep/er") || strings.Contains(got, "/home/jo/deep/er/est") {
+		t.Errorf("depth 3 under /home is /home/jo/deep/er: %s", got)
+	}
+	tl := tool(t, f.machine(), "disk_folders")
+	for _, bad := range []map[string]any{{"depth": 0.0}, {"limit": 0.0}, {"depth": "deep"}, {"path": "relative/dir"}, {"path": "/nope"}, {"path": "/var/log/big.log"}} {
+		if _, err := tl.Run(bad); err == nil {
+			t.Errorf("%v was accepted", bad)
+		}
+	}
+	for i := 0; i < 120; i++ {
+		f.file(fmt.Sprintf("many/d%03d/f", i), "x")
+	}
+	if r := folders(t, f.machine(), map[string]any{"path": "/many", "limit": 500.0}); len(r.Largest) != 100 {
+		t.Errorf("limit held at %d, not 100", len(r.Largest))
+	}
+}
+
+// 1804/AC3: given a mount below the path, then it is never entered or counted, and is named.
+func TestFoldersNeverCrossIntoAnotherFilesystem(t *testing.T) {
+	f := aFullDisk(t)
+	m := f.machine()
+	m.DevOf = func(path string, info fs.FileInfo) uint64 {
+		if path == "/var/lib/docker" {
+			return 7
+		}
+		return 1
+	}
+	r := folders(t, m, nil)
+	if strings.Contains(paths(r), "docker") || len(r.Skipped) != 1 || r.Skipped[0] != "/var/lib/docker" {
+		t.Errorf("%s, skipped %v", paths(r), r.Skipped)
+	}
+	if r.Bytes > 14*mb {
+		t.Errorf("total %d includes the mount", r.Bytes)
+	}
+}
+
+// 1804/AC4: given folders it cannot read, then they are counted and named and the rest is still answered.
+func TestUnreadableFoldersAreCountedAndNamed(t *testing.T) {
+	f := aFullDisk(t)
+	m := f.machine()
+	real := os.ReadDir
+	m.ReadDir = func(p string) ([]os.DirEntry, error) {
+		if strings.HasSuffix(p, "/var/log") || strings.HasSuffix(p, "/overlay2/b") {
+			return nil, fmt.Errorf("open %s: permission denied", p)
+		}
+		return real(p)
+	}
+	r := folders(t, m, map[string]any{"depth": 3.0})
+	if r.Unreadable != 2 || strings.Join(r.UnreadableFolders, ",") != "/var/lib/docker/overlay2/b,/var/log" {
+		t.Errorf("%d: %v", r.Unreadable, r.UnreadableFolders)
+	}
+	if r.Partial || !strings.Contains(strings.Join(r.Said, "\n"), "2 folders could not be read") {
+		t.Errorf("%+v", r)
+	}
+}
+
+// 1804/AC5: given a walk that outlasts its bound, then it answers what it measured, partial, with where it stopped.
+func TestALongWalkAnswersPartialAndSaysWhereItStopped(t *testing.T) {
+	f := aFullDisk(t)
+	m := f.machine()
+	now := time.Unix(0, 0)
+	m.Clock = func() time.Time { now = now.Add(10 * time.Second); return now }
+	r := folders(t, m, nil)
+	if !r.Partial || r.StoppedAt == "" || len(r.Said) < 2 || !strings.HasPrefix(r.Said[0], "PARTIAL") || !strings.Contains(r.Said[0], r.StoppedAt) {
+		t.Errorf("%+v", r)
+	}
+}
+
+// 1804/AC6: a hard link is counted once, and the tool changes nothing.
+func TestAHardLinkIsCountedOnce(t *testing.T) {
+	f := newFake(t)
+	f.megabytes("a/big", 5)
+	if err := os.Link(f.root+"/a/big", f.root+"/a/again"); err != nil {
+		t.Skip(err)
+	}
+	r := folders(t, f.machine(), nil)
+	if r.Bytes > 6*mb {
+		t.Errorf("counted twice: %d", r.Bytes)
+	}
+}
+
+// 1804/AC7: the bound sits below the 30 s the tool runner gives a call, so a partial answer reaches its caller.
+func TestTheWalkBoundIsBelowTheToolRunnersCallLimit(t *testing.T) {
+	if FolderBudget >= 30*time.Second {
+		t.Errorf("the budget %s is not below the 30 s a call gets", FolderBudget)
+	}
+}

modules/disk-load/cmd/disk-load/machine.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"context"
 	"fmt"
+	"io/fs"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -53,6 +54,13 @@ type Machine struct {
 	Run    Runner
 	Wait   func(time.Duration)
 	Statfs func(path string) (FSStat, error)
+
+	// The folder walk's seams, all optional: the folder reader, the filesystem a path is on, the clock and
+	// the time the walk may take (60 s when zero).
+	ReadDir func(path string) ([]os.DirEntry, error)
+	DevOf   func(path string, info fs.FileInfo) uint64
+	Clock   func() time.Time
+	Budget  time.Duration
 }
 
 // Here is the machine this process runs on.

modules/disk-load/cmd/disk-load/tools.go

@@ -136,6 +136,34 @@ func Tools(m *Machine) []stdio.Tool {
 				}, nil
 			},
 		},
+		{
+			Name: "disk_folders",
+			Description: "Which folders fill a disk, like du -x: the largest folders under a path, measured on disk (allocated bytes, a hard link " +
+				"once), staying on the path's one filesystem (a mount below it is named, never entered). path defaults to /, depth to 2 (at most 3), " +
+				"limit to 20 (at most 100). Sizes in bytes and GiB. It reads every folder the tool runner can read, none of the content; folders " +
+				"it cannot read are counted and named. It stops after 25 s and answers what it measured so far, marked partial, with where it stopped. " +
+				"Replaces du. (r)",
+			Input: map[string]any{
+				"path":  map[string]any{"type": "string", "description": "the absolute folder to measure (default /)"},
+				"depth": map[string]any{"type": "integer", "description": "how many levels below path to rank (default 2, at most 3)"},
+				"limit": map[string]any{"type": "integer", "description": "how many folders to answer (default 20, at most 100)"},
+			},
+			Run: func(args map[string]any) (any, error) {
+				depth, err := count(args, "depth", 2, 1, 3)
+				if err != nil {
+					return nil, err
+				}
+				limit, err := count(args, "limit", 20, 1, 100)
+				if err != nil {
+					return nil, err
+				}
+				path := text(args, "path")
+				if path == "" {
+					path = "/"
+				}
+				return m.Folders(path, depth, limit)
+			},
+		},
 		{
 			Name: "disk_filesystems",
 			Description: "The space of every filesystem that stores data (not proc, tmpfs or overlay layers): size, used and free in GiB, " +

modules/disk-load/module.json

@@ -5,6 +5,7 @@
     "disk_load",
     "disk_top",
     "disk_filesystems",
+    "disk_folders",
     "disk_devices",
     "cpu_top"
   ],

modules/docker/README.md

@@ -160,6 +160,7 @@ A failure is an error naming how it failed, never an empty answer.
 | `docker_disk_usage` | r | `docker system df -v`: total, active and reclaimable per kind, with the largest of each |
 | `docker_networks` | r | networks, subnets, and the containers on each |
 | `docker_volumes` | r | volumes, who mounts each, whether the mesh holds one of them, anonymous or not, and sizes if asked |
+| `docker_volumes_remove_anonymous` | a | leftover anonymous volumes no container mounts in any state (so none the mesh holds), optionally created before a time; each other volume answered with why it stays; none can be named. **A dry run unless `dry_run` is false, which needs `why`. Never forced** (issue 1796). Sizes only when `sizes` is true (docker is slow on very many volumes); at most `limit` (default 200) per call |
 | `docker_events` | r | the runtime's events over a window ending now (default 60 min, at most 24 h), without exec noise unless asked; **an exec's command line is shown with any secret it carried as `[redacted: <what it was>]`** |
 | `docker_daemon_config` | r | `daemon.json` as on disk, `docker info`'s essentials, and keys the daemon has not taken yet |
 | `docker_unlabelled` | r | the containers the mesh does not hold: the cleanup list |

modules/docker/cmd/docker-tools/docker.go

@@ -944,16 +944,9 @@ func (c *Client) Volumes(ctx context.Context, unmountedOnly, sizes bool) (map[st
 	}
 	size := map[string]string{}
 	if sizes {
-		out, err := c.docker(ctx, "system", "df", "--verbose", "--format", "{{json .}}")
+		if size, err = c.volumeSizes(ctx); err != nil {
-		if err != nil {
 			return nil, err
 		}
-		var v struct{ Volumes []map[string]any }
-		if err := json.Unmarshal([]byte(out), &v); err == nil {
-			for _, vol := range v.Volumes {
-				size[fmt.Sprint(vol["Name"])] = fmt.Sprint(vol["Size"])
-			}
-		}
 	}
 	vols := []map[string]any{}
 	if len(lines(names)) > 0 {
@@ -1215,3 +1208,134 @@ func (c *Client) DaemonConfig(ctx context.Context) (map[string]any, error) {
 	answer["note"] = "keys read only at start take effect at the daemon's next restart; with live-restore on, a restart keeps every container running"
 	return answer, nil
 }
+
+// volumeSizes is every volume's size by name, from docker system df -v, which walks every volume:
+// on a machine with a thousand of them it does not answer within a call's bound.
+func (c *Client) volumeSizes(ctx context.Context) (map[string]string, error) {
+	size := map[string]string{}
+	out, err := c.docker(ctx, "system", "df", "--verbose", "--format", "{{json .}}")
+	if err != nil {
+		return nil, err
+	}
+	var v struct{ Volumes []map[string]any }
+	if err := json.Unmarshal([]byte(out), &v); err == nil {
+		for _, vol := range v.Volumes {
+			size[fmt.Sprint(vol["Name"])] = fmt.Sprint(vol["Size"])
+		}
+	}
+	return size, nil
+}
+
+// RemoveVolumesAsk is what docker_volumes_remove_anonymous is asked to take.
+type RemoveVolumesAsk struct {
+	DryRun        bool
+	Why           string
+	CreatedBefore *time.Time
+	Sizes         bool
+	Limit         int // how many to remove in one call; 0 is 200
+}
+
+// RemoveAnonymousVolumes removes the leftover anonymous volumes (novox/hq issue 1796): those docker
+// labels anonymous, which no container mounts in any state, so none a mesh-held container holds. The
+// classification is Volumes' own, not a copy. Every other volume is answered with why it stays. Each
+// is removed by its own `docker volume rm`, never forced and never `volume prune`, so one the daemon
+// refuses is reported and the rest still go.
+func (c *Client) RemoveAnonymousVolumes(ctx context.Context, a RemoveVolumesAsk) (map[string]any, error) {
+	if !a.DryRun && strings.TrimSpace(a.Why) == "" {
+		return nil, fmt.Errorf("why is required when dry_run is false")
+	}
+	all, err := c.Volumes(ctx, false, false)
+	if err != nil {
+		return nil, err
+	}
+	candidates := []string{}
+	skipped := []map[string]any{}
+	skip := func(name, why string) { skipped = append(skipped, map[string]any{"name": name, "why": why}) }
+	for _, v := range all["volumes"].([]map[string]any) {
+		name := fmt.Sprint(v["name"])
+		switch by := v["mounted_by"].([]map[string]any); {
+		case v["anonymous"] != true:
+			skip(name, "not anonymous: a named volume is data")
+		case v["mesh_held"] == true:
+			skip(name, "mounted by a container the mesh holds")
+		case len(by) > 0:
+			skip(name, fmt.Sprintf("mounted by %v (%v)", by[0]["container"], by[0]["state"]))
+		case a.CreatedBefore != nil && !volumeOlder(fmt.Sprint(v["created"]), *a.CreatedBefore):
+			skip(name, "not created before "+a.CreatedBefore.Format(time.RFC3339)+" (created "+fmt.Sprint(v["created"])+")")
+		default:
+			candidates = append(candidates, name)
+		}
+	}
+	answer := map[string]any{"dry_run": a.DryRun, "candidates": len(candidates)}
+	// Sizes are asked for, never needed: the listing walks every volume and may not answer, and
+	// then the call answers without them. Nothing below depends on it.
+	sizes := map[string]string{}
+	if a.Sizes {
+		if got, err := c.volumeSizes(ctx); err != nil {
+			answer["sizes_unknown"] = err.Error()
+		} else {
+			sizes = got
+			answer["sizes"] = sizes
+		}
+	}
+	sum := func(names []string) int64 {
+		var t int64
+		for _, n := range names {
+			t += max(Bytes(sizes[n]), 0)
+		}
+		return t
+	}
+	if a.DryRun {
+		answer["skipped"] = skipped
+		answer["would_remove"] = candidates
+		if len(sizes) > 0 {
+			answer["would_free_bytes"] = sum(candidates)
+		}
+		answer["note"] = "nothing was removed: call again with dry_run false and why to remove them (limit volumes at most per call)"
+		return answer, nil
+	}
+	limit := a.Limit
+	if limit <= 0 {
+		limit = 200
+	}
+	take := candidates
+	if len(take) > limit {
+		take = candidates[:limit]
+	}
+	removed := []string{}
+	// Chunks of a hundred in one `docker volume rm`, so a thousand volumes are ten calls; a chunk
+	// docker refuses any of is done again one by one, so what it refuses is named.
+	for i := 0; i < len(take); i += 100 {
+		chunk := take[i:min(i+100, len(take))]
+		if _, err := c.docker(ctx, append([]string{"volume", "rm"}, chunk...)...); err == nil {
+			removed = append(removed, chunk...)
+			continue
+		}
+		for _, name := range chunk {
+			if _, err := c.docker(ctx, "volume", "rm", name); err != nil {
+				// The batch took it before it refused another (or before its bound ran out):
+				// a volume that is no longer there is a removed one.
+				if strings.Contains(strings.ToLower(err.Error()), "no such volume") {
+					removed = append(removed, name)
+					continue
+				}
+				skip(name, "docker refused: "+err.Error())
+				continue
+			}
+			removed = append(removed, name)
+		}
+	}
+	answer["skipped"] = skipped
+	answer["removed"], answer["count"], answer["why"] = removed, len(removed), a.Why
+	answer["remaining"] = len(candidates) - len(take)
+	if len(sizes) > 0 {
+		answer["freed_bytes"] = sum(removed)
+	}
+	return answer, nil
+}
+
+// volumeOlder is whether a volume's CreatedAt is before the cutoff; one that cannot be read is not.
+func volumeOlder(created string, cutoff time.Time) bool {
+	t, err := time.Parse(time.RFC3339Nano, created)
+	return err == nil && t.Before(cutoff)
+}

modules/docker/cmd/docker-tools/docker_test.go

@@ -431,3 +431,145 @@ func TestEventsCoveringTheWholeWindowSayItIsCompleteAndFilterTheTypeHere(t *test
 		t.Fatalf("a full buffer reaching past the window: %v", got)
 	}
 }
+
+// 1796/AC1: only anonymous volumes nothing mounts go, each answered; a named, a mounted and a too young one stay with why.
+func TestRemoveAnonymousVolumesTakesOnlyTheUnmountedAnonymousOnes(t *testing.T) {
+	f := machine().
+		on("docker volume ls --quiet", Ran{Stdout: "webdata\nanonmounted\nold\nyoung\nnamed\n"}).
+		on("docker volume inspect", Ran{Stdout: `[
+{"Name":"webdata","Driver":"local","CreatedAt":"2026-01-01T00:00:00Z","Labels":{"com.docker.volume.anonymous":""}},
+{"Name":"old","Driver":"local","CreatedAt":"2026-09-01T00:00:00Z","Labels":{"com.docker.volume.anonymous":""}},
+{"Name":"young","Driver":"local","CreatedAt":"2026-10-04T11:00:00Z","Labels":{"com.docker.volume.anonymous":""}},
+{"Name":"named","Driver":"local","CreatedAt":"2026-01-01T00:00:00Z"}]`}).
+		on("docker system df --verbose", Ran{Stdout: `{"Volumes":[{"Name":"old","Size":"1.5MB"},{"Name":"young","Size":"1kB"}]}`}).
+		on("docker volume rm old", Ran{Stdout: "old\n"})
+	c := client(f, 1000)
+	before := time.Date(2026, 10, 3, 0, 0, 0, 0, time.UTC)
+	got, err := c.RemoveAnonymousVolumes(context.Background(), RemoveVolumesAsk{DryRun: true, Sizes: true, CreatedBefore: &before})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if f.ran("docker volume rm") || !reflect.DeepEqual(got["would_remove"], []string{"old"}) {
+		t.Fatalf("dry run: %v %+v", got, f.calls)
+	}
+	if got["would_free_bytes"] != int64(1500000) || got["sizes"].(map[string]string)["old"] != "1.5MB" {
+		t.Fatalf("dry run size: %v", got)
+	}
+	skipped := got["skipped"].([]map[string]any)
+	why := map[string]string{}
+	for _, s := range skipped {
+		why[s["name"].(string)] = s["why"].(string)
+	}
+	if len(why) != 3 || !strings.Contains(why["webdata"], "mesh holds") || why["young"] == "" || why["named"] == "" {
+		t.Fatalf("skipped: %v", skipped)
+	}
+	got, err = c.RemoveAnonymousVolumes(context.Background(), RemoveVolumesAsk{Why: "leftovers", Sizes: true, CreatedBefore: &before})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !f.ran("docker volume rm old") || got["count"] != 1 || !reflect.DeepEqual(got["removed"], []string{"old"}) {
+		t.Fatalf("removed: %v %+v", got, f.calls)
+	}
+	if got["freed_bytes"] != int64(1500000) {
+		t.Fatalf("freed: %v", got)
+	}
+	for _, c := range f.calls {
+		if len(c.args) > 1 && c.args[0] == "volume" && c.args[1] == "rm" && (len(c.args) != 3 || c.args[2] != "old") {
+			t.Errorf("reached too far: %v", c.args)
+		}
+	}
+}
+
+// 1796/AC2: a volume that is mounted by a mesh-held container is never removed; the tool takes no name.
+func TestRemoveAnonymousVolumesRefusesANamedVolumeAndKeepsWhatTheMeshHolds(t *testing.T) {
+	for _, tool := range tools(client(&fake{}, 1000)) {
+		if tool.Name != "docker_volumes_remove_anonymous" {
+			continue
+		}
+		for _, k := range []string{"name", "names", "volume", "volumes"} {
+			if _, err := tool.Run(map[string]any{k: "x", "dry_run": false, "why": "w"}); err == nil {
+				t.Errorf("%s accepted", k)
+			}
+		}
+		if _, err := tool.Run(map[string]any{"dry_run": false}); err == nil {
+			t.Error("a removal without why was accepted")
+		}
+		if _, err := tool.Run(map[string]any{"created_before": "yesterday"}); err == nil {
+			t.Error("a bad time was accepted")
+		}
+		return
+	}
+	t.Fatal("tool not served")
+}
+
+// 1796/AC3: on a machine with a very large set of volumes docker's size listing does not answer in
+// time; the tool still answers, and removal never depends on it.
+func TestRemoveAnonymousVolumesAnswersWhenTheSizeListingDoesNot(t *testing.T) {
+	f := (&fake{}).
+		on("docker ps --all --quiet --no-trunc", Ran{}).
+		on("docker volume ls --quiet", Ran{Stdout: "a1\na2\na3\n"}).
+		on("docker volume inspect", Ran{Stdout: `[{"Name":"a1","Labels":{"com.docker.volume.anonymous":""}},{"Name":"a2","Labels":{"com.docker.volume.anonymous":""}},{"Name":"a3","Labels":{"com.docker.volume.anonymous":""}}]`}).
+		on("docker system df", Ran{Status: 124, Err: "no answer within 20 s"}).
+		on("docker volume rm", Ran{Stdout: "ok\n"})
+	c := client(f, 1000)
+	got, err := c.RemoveAnonymousVolumes(context.Background(), RemoveVolumesAsk{DryRun: true})
+	if err != nil || f.ran("docker system df") || !reflect.DeepEqual(got["would_remove"], []string{"a1", "a2", "a3"}) {
+		t.Fatalf("default dry run: %v %v %+v", got, err, f.calls)
+	}
+	got, err = c.RemoveAnonymousVolumes(context.Background(), RemoveVolumesAsk{DryRun: true, Sizes: true})
+	if err != nil || !reflect.DeepEqual(got["would_remove"], []string{"a1", "a2", "a3"}) || got["sizes_unknown"] == nil {
+		t.Fatalf("sizes asked, df silent: %v %v", got, err)
+	}
+	got, err = c.RemoveAnonymousVolumes(context.Background(), RemoveVolumesAsk{Why: "w", Sizes: true, Limit: 2})
+	if err != nil || got["count"] != 2 || got["remaining"] != 1 || !f.ran("docker volume rm a1 a2") {
+		t.Fatalf("removal: %v %v %+v", got, err, f.calls)
+	}
+}
+
+// 1796/AC4: a batch docker half-did is settled by name: what is already gone counts as removed, what is in use stays with why.
+func TestRemoveAnonymousVolumesCountsWhatAFailedBatchAlreadyRemoved(t *testing.T) {
+	f := (&fake{}).
+		on("docker ps --all --quiet --no-trunc", Ran{}).
+		on("docker volume ls --quiet", Ran{Stdout: "a1\na2\na3\n"}).
+		on("docker volume inspect", Ran{Stdout: `[{"Name":"a1","Labels":{"com.docker.volume.anonymous":""}},{"Name":"a2","Labels":{"com.docker.volume.anonymous":""}},{"Name":"a3","Labels":{"com.docker.volume.anonymous":""}}]`}).
+		on("docker volume rm a1 a2 a3", Ran{Status: 1, Stdout: "a1\n", Stderr: "Error response from daemon: remove a2: volume is in use - [c1]\n"}).
+		on("docker volume rm a1", Ran{Status: 1, Stderr: "Error response from daemon: get a1: no such volume\n"}).
+		on("docker volume rm a2", Ran{Status: 1, Stderr: "Error response from daemon: remove a2: volume is in use - [c1]\n"}).
+		on("docker volume rm a3", Ran{Stdout: "a3\n"})
+	got, err := client(f, 1000).RemoveAnonymousVolumes(context.Background(), RemoveVolumesAsk{Why: "w"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	sk := got["skipped"].([]map[string]any)
+	if !reflect.DeepEqual(got["removed"], []string{"a1", "a3"}) || got["count"] != 2 || len(sk) != 1 || sk[0]["name"] != "a2" || !strings.Contains(sk[0]["why"].(string), "in use") {
+		t.Fatalf("%v", got)
+	}
+}
+
+// 1796/AC5: removal goes in batches of a hundred names.
+func TestRemoveAnonymousVolumesRemovesInBatchesOfAHundred(t *testing.T) {
+	names, entries := []string{}, []string{}
+	for i := 0; i < 250; i++ {
+		n := fmt.Sprintf("v%03d", i)
+		names = append(names, n)
+		entries = append(entries, `{"Name":"`+n+`","Labels":{"com.docker.volume.anonymous":""}}`)
+	}
+	f := (&fake{}).
+		on("docker ps --all --quiet --no-trunc", Ran{}).
+		on("docker volume ls --quiet", Ran{Stdout: strings.Join(names, "\n")}).
+		on("docker volume inspect", Ran{Stdout: "[" + strings.Join(entries, ",") + "]"}).
+		on("docker volume rm", Ran{Stdout: "ok\n"})
+	got, err := client(f, 1000).RemoveAnonymousVolumes(context.Background(), RemoveVolumesAsk{Why: "w", Limit: 250})
+	if err != nil || got["count"] != 250 {
+		t.Fatalf("%v %v", got, err)
+	}
+	sizes := []int{}
+	for _, c := range f.calls {
+		if len(c.args) > 1 && c.args[0] == "volume" && c.args[1] == "rm" {
+			sizes = append(sizes, len(c.args)-2)
+		}
+	}
+	if !reflect.DeepEqual(sizes, []int{100, 100, 50}) {
+		t.Fatalf("batches %v", sizes)
+	}
+}

modules/docker/cmd/docker-tools/main.go

@@ -11,6 +11,7 @@ import (
 	"math"
 	"os"
 	"strings"
+	"time"
 
 	stdio "git.novox.be/novox/mesh-sdk/go"
 )
@@ -286,6 +287,40 @@ func tools(c *Client) []stdio.Tool {
 				return c.Volumes(ctx, flag(args, "unmounted", false), flag(args, "sizes", false))
 			},
 		},
+		{
+			Name: "docker_volumes_remove_anonymous",
+			Description: "Remove the leftover anonymous volumes (novox/hq issue 1796): only a volume docker labels anonymous (as docker_volumes says), which no container mounts in any state " +
+				"and so none the mesh holds, and with created_before only one created before it. Every other volume is answered with why it stays; a named volume is data and is never taken, " +
+				"and no volume can be named. Each is removed on its own, never forced; the answer has the count and names removed. With sizes true the answer has each volume's size and the bytes freed; docker's size listing is slow on many volumes, so it is asked for, and when it does not answer the call answers without it. At most limit are removed per call, in batches. " +
+				"A dry run by default; dry_run false needs why. Replaces docker volume rm and docker volume prune. (a)",
+			Input: map[string]any{
+				"dry_run":        map[string]any{"type": "boolean", "description": "list only (default true)"},
+				"why":            map[string]any{"type": "string", "description": "why: required when dry_run is false"},
+				"created_before": map[string]any{"type": "string", "description": "RFC 3339 time: only volumes created before it (default: any age)"},
+				"sizes":          map[string]any{"type": "boolean", "description": "also read each volume's size and the bytes freed (default false: docker walks every volume for it and on a machine with very many may not answer; the call then answers without sizes)"},
+				"limit":          map[string]any{"type": "integer", "description": "how many to remove in one call (default 200, at most 2000); the answer says how many remain, call again for them"},
+			},
+			Run: func(args map[string]any) (any, error) {
+				for _, k := range []string{"name", "names", "volume", "volumes"} {
+					if _, ok := args[k]; ok {
+						return nil, fmt.Errorf("%s: this tool takes no volume by name; it removes only unmounted anonymous volumes", k)
+					}
+				}
+				limit, err := bounded(args, "limit", 200, 2000)
+				if err != nil {
+					return nil, err
+				}
+				ask := RemoveVolumesAsk{DryRun: flag(args, "dry_run", true), Why: optional(args, "why"), Sizes: flag(args, "sizes", false), Limit: limit}
+				if s := optional(args, "created_before"); s != "" {
+					t, err := time.Parse(time.RFC3339, s)
+					if err != nil {
+						return nil, fmt.Errorf("created_before must be an RFC 3339 time such as 2026-10-01T00:00:00Z")
+					}
+					ask.CreatedBefore = &t
+				}
+				return c.RemoveAnonymousVolumes(ctx, ask)
+			},
+		},
 		{
 			Name: "docker_events",
 			Description: "What the runtime did in a window ending now (default the last 60 minutes, at most 24 hours): containers created, started, died, health changes, images pulled — with mesh_held. Exec events are left out unless asked; " +

modules/docker/module.json

@@ -33,6 +33,7 @@
     "docker_disk_usage",
     "docker_networks",
     "docker_volumes",
+    "docker_volumes_remove_anonymous",
     "docker_events",
     "docker_daemon_config",
     "docker_unlabelled",

modules/gitea/bind.ts

@@ -0,0 +1,44 @@
+// **A consumer that cannot be bound yet is bound again, never fatal** (novox/hq issue 1793). When the tool runtime
+// starts this bundle, the runtime's answer to "bind this module's consumer" can be "no responders" for a few seconds (the
+// runtime restarted by a delivery, the bus not yet serving the stream). That rejection, left unhandled at the top of
+// index.ts, ended the bundle: nothing heard `mesh-controller.checked` again, and a verdict that landed later never
+// reached the forge's statuses. A bind that fails is said and asked again with a growing wait until it holds.
+
+/** How long to wait before the nth new attempt (1-based): 2 s, 5 s, 10 s, then every 30 s. */
+export function bindWait(attempt: number): number {
+  return [2_000, 5_000, 10_000][attempt - 1] ?? 30_000;
+}
+
+/**
+ * Binds with `bind`, asking again after each failure, until it holds. `sleep` is the wait; `say` how a failure is said.
+ * Never rejects; resolves once the bind holds.
+ */
+export async function bindUntilHeld(what: string, bind: () => Promise<unknown>,
+  sleep: (ms: number) => Promise<void> = (ms) => new Promise((r) => setTimeout(r, ms)),
+  say: (line: string) => void = (line) => console.error(line)): Promise<void> {
+  for (let attempt = 1; ; attempt++) {
+    try {
+      await bind();
+      if (attempt > 1) say(`[gitea] ${what} is bound after ${attempt} attempts`);
+      return;
+    } catch (err) {
+      const wait = bindWait(attempt);
+      say(`[gitea] ${what} could not be bound (${err instanceof Error ? err.message : String(err)}); asking again in ${wait / 1000}s`);
+      await sleep(wait);
+    }
+  }
+}
+
+/**
+ * **Starts the binds without making the bundle wait for them** (novox/hq issue 1793). The launcher imports the bundle
+ * and then answers the runtime's handshake, which the runtime gives 10 s and then kills the bundle without starting it
+ * again; a bind awaited at the top of the module that stays refused longer ends the bundle all the same. So this
+ * returns at once: the binds run in the order given, each until it holds, and `done` is called after the last.
+ */
+export function bindInBackground(binds: [what: string, bind: () => Promise<unknown>][], done: () => void,
+  sleep?: (ms: number) => Promise<void>, say?: (line: string) => void): void {
+  void (async () => {
+    for (const [what, bind] of binds) await bindUntilHeld(what, bind, sleep, say);
+    done();
+  })();
+}

modules/gitea/cmd/forge-account-provider/builder_test.go

@@ -179,7 +179,7 @@ func newTeamRig(t *testing.T) *teamRig {
 	svc := NewService(Config{Node: "novox", HostFile: host, OriginsFile: origins, Port: 222,
 		Forge: forgehttp.Client{URL: srv.URL, User: "mesh-admin", PasswordFile: pw}, Runner: runner, Log: func(string, ...any) {}})
 	svc.loaded = true
-	svc.loadedFrom["mesh-build-go"], svc.loadedFrom["mesh-build-node"] = true, true
+	svc.loadedFrom["mesh-build-go"], svc.loadedFrom["mesh-build-node"], svc.loadedFrom["mesh-build-image"] = true, true, true
 	return &teamRig{t: t, bus: newBus(), forge: forge, svc: svc, runner: runner}
 }
 
@@ -347,7 +347,7 @@ func TestABuildModulesEntryWaitsForItsOwnBuilderKey(t *testing.T) {
 }
 
 func TestTheKindOfAModulesKeyAndItsForgeUser(t *testing.T) {
-	for module, want := range map[string]string{"mesh-build-go": "nox-builder", "mesh-build-node": "nox-builder", "ssh-client": "nox-agent", "anything-else": "nox-agent"} {
+	for module, want := range map[string]string{"mesh-build-go": "nox-builder", "mesh-build-node": "nox-builder", "mesh-build-image": "nox-builder", "ssh-client": "nox-agent", "anything-else": "nox-agent"} {
 		got, err := (&Service{}).valuesForUser("ace", module)
 		if err != nil || got != want {
 			t.Errorf("%s: %q, %v; want %q", module, got, err, want)

modules/gitea/cmd/forge-account-provider/watch_test.go

@@ -38,7 +38,7 @@ func newWatched(t *testing.T) *watched {
 	r.svc.OnKeys = func(string) { n++ }
 	r.svc.cfg.Log = func(f string, a ...any) { mu.Lock(); logs = append(logs, fmt.Sprintf(f, a...)); mu.Unlock() }
 	w := &watched{teamRig: r, sources: map[string]*fakeKeys{}, passes: &n, logs: &logs, mu: mu}
-	for _, module := range []string{"ssh-client", "mesh-build-go", "mesh-build-node"} {
+	for _, module := range []string{"ssh-client", "mesh-build-go", "mesh-build-node", "mesh-build-image"} {
 		w.sources[module] = &fakeKeys{}
 		if err := r.svc.WatchSource(context.Background(), module, w.sources[module]); err != nil {
 			t.Fatal(err)
@@ -154,7 +154,7 @@ func TestTheManifestReadsTheBuildModulesKeys(t *testing.T) {
 	if err := json.Unmarshal(raw, &m); err != nil {
 		t.Fatal(err)
 	}
-	for _, state := range []string{"mesh-controller.assignments", "ssh-client.keys", "mesh-build-go.keys", "mesh-build-node.keys"} {
+	for _, state := range []string{"mesh-controller.assignments", "ssh-client.keys", "mesh-build-go.keys", "mesh-build-node.keys", "mesh-build-image.keys"} {
 		if !slices.Contains(m.Reads, state) {
 			t.Errorf("gitea's reads %v lack %q", m.Reads, state)
 		}

modules/gitea/index.ts

@@ -47,6 +47,7 @@ import { CHECK_CONTEXT, REPO_CHECK_CONTEXT, commentFor, composedGate, groupGateS
 import { GateWriter, clonedAs, type BuildStarted } from "./gate.js";
 import { HOOK_PATH, HOOK_PORT, Pace, claimHead, ensureSystemHook, eventsTool, keptSecret, receiver, type ForgeEvent } from "./webhook.js";
 import { keepSiblings, noteComposed, noteVerdict, readSiblings, siblingsFile, siblingsOf, weighSiblings } from "./siblings.js";
+import { bindInBackground } from "./bind.js";
 import { announcementOf, keepTook, lateVerdictComment, outOfDateWords, sameCommit, tookFile, weighTrunks } from "./trunk.js";
 
 // Without a way to a token — configured, or mintable with the admin account (token.ts) — there is
@@ -590,15 +591,18 @@ if (gitea) {
   tick(() => pollRepos(client), 60_000);
   tick(() => pollMerged(client), () => pace.every());
   tick(() => pollPulls(client), () => pace.every());
-  await on("mesh-controller.checked", (event) => {
+  // Bound again until they hold, and not awaited (bind.ts, issue 1793): the runtime kills a bundle that has not answered its
-    const c = (event.body ?? {}) as Checked;
+  // handshake in 10 s, so the import must end while a refused bind is still asked again.
-    // A head's own verdict takes its turn after every write of that head's gate already asked for (gate.ts).
+  bindInBackground([
-    // A verdict of a check asked before the one now pending is an older run's, and dropped (novox/hq issue 456).
+    ["mesh-controller.checked", () => on("mesh-controller.checked", (event) => {
-    if (!c.group && c.owner && c.repo && c.commit) {
+      const c = (event.body ?? {}) as Checked;
-      return gates.verdict(c.owner, c.repo, c.commit, () => setVerdict(client, event), c.id);
+      // A head's own verdict takes its turn after every write of that head's gate already asked for (gate.ts).
-    }
+      // A verdict of a check asked before the one now pending is an older run's, and dropped (novox/hq issue 456).
-    return setVerdict(client, event);
+      if (!c.group && c.owner && c.repo && c.commit) {
-  });
+        return gates.verdict(c.owner, c.repo, c.commit, () => setVerdict(client, event), c.id);
-  await on("node-build-agent.started", buildStarted);
+      }
-  console.log("[gitea] watching for new repositories and merged pull requests");
+      return setVerdict(client, event);
+    })],
+    ["node-build-agent.started", () => on("node-build-agent.started", buildStarted)],
+  ], () => console.log("[gitea] watching for new repositories and merged pull requests"));
 }

modules/gitea/internal/forgeaccount/account.go

@@ -195,7 +195,7 @@ const BuilderUser = "nox-builder"
 
 // BuildModules are the modules whose keys are the builders' (kind builder), by their name, which is also the name of
 // the account each runs as (ADR 0466 §1).
-var BuildModules = []string{"mesh-build-go", "mesh-build-node"}
+var BuildModules = []string{"mesh-build-go", "mesh-build-node", "mesh-build-image"}
 
 // KindOfModule is the kind of key a consumer module's entry is made for: builder for a build module, machine for any
 // other (ssh-client's).

modules/gitea/internal/forgeaccount/builder_test.go

@@ -12,7 +12,7 @@ func TestTheBuildModulesHaveOneForgeUserAndTheMachinesKeepTheirs(t *testing.T) {
 	if ForgeUser("Not A Node", "builder") != "" {
 		t.Errorf("a name no account could be named for got a user")
 	}
-	for module, want := range map[string]string{"mesh-build-go": "builder", "mesh-build-node": "builder", "ssh-client": "machine", "": "machine"} {
+	for module, want := range map[string]string{"mesh-build-go": "builder", "mesh-build-node": "builder", "mesh-build-image": "builder", "ssh-client": "machine", "": "machine"} {
 		if got := KindOfModule(module); got != want {
 			t.Errorf("KindOfModule(%q) = %s, want %s", module, got, want)
 		}

modules/gitea/merge.ts

@@ -12,7 +12,7 @@ import { mergeableUnder, newestByContext } from "./checks.js";
 import { MERGE_METHODS, Refused, checkName } from "./guard.js";
 import { CHECK_CONTEXT, REPO_CHECK_CONTEXT } from "./pulls.js";
 import { approvedHeadsOf, groupRefusal, memberKey, namesSiblings, notApproved, readSiblings, siblingOutOfDate, siblingsFile } from "./siblings.js";
-import { announcementOf, askedWords, outOfDateWords, sameCommit, tookFile, tookWords, twelve, verdictAtTrunk } from "./trunk.js";
+import { announcementOf, askedWords, outOfDateWords, sameCommit, tookFile, tookWords, twelve, verdictAtTrunk, waitsForComposed } from "./trunk.js";
 
 /** A head named for a merge: at least 12 hex characters of its sha (novox/hq issue 381), up to a sha-256 commit's 64. */
 const REVIEWED_HEAD = /^[0-9a-f]{12,64}$/;
@@ -117,6 +117,14 @@ export function mergeTool(gitea: GiteaClient, given: MergeDeps): ToolDefinition
           : at.judged ? `was judged against trunk ${twelve(at.judged)}` : "names no trunk commit it was judged against";
         const took = tookWords(tookFile(deps.stateDir), `${owner}/${repo}`);
         const head = twelve(pull.head_sha), now = twelve(trunkHead);
+        // **A member that waits for its group's composed check is not announced again** (novox/hq issue 1106): its own
+        // check can only say "composed" once more, so an ask here brought a verdict naming no trunk and the next merge was
+        // refused the same way for ever. The composed check is mesh-delivery's to ask; this says whose verdict is awaited.
+        if (waitsForComposed(checks[CHECK_CONTEXT])) {
+          throw new Refused(`${owner}/${repo}#${number} is not merged: its merge gate ${checks[CHECK_CONTEXT]?.description}; the ` +
+            `verdict that names its trunk commit is its group's composed check's, and mesh-delivery asks it, this tool asks no check ` +
+            `(main is now ${now}). Ask again once the group's composed check has passed. Nothing was merged`);
+        }
         if (at.onItsWay) {
           throw new Refused(`${owner}/${repo}#${number} is not merged: its verdict ${judged}, and ${pull.base} is now ` +
             `${now}. Its check is already asked and not yet answered (${checks[CHECK_CONTEXT]?.description}), so it is not ` +

modules/gitea/module.json

@@ -542,6 +542,7 @@
     "mesh-controller.assignments",
     "ssh-client.keys",
     "mesh-build-go.keys",
-    "mesh-build-node.keys"
+    "mesh-build-node.keys",
+    "mesh-build-image.keys"
   ]
 }

modules/gitea/pulls.ts

@@ -226,6 +226,10 @@ function repoWrong(repo: Layer | undefined, facts: RepoCheckFacts): boolean {
   return !!repo && repoStatus(repo, facts).state !== "success";
 }
 
+/** What a group member's gate says while the group's composed check is the one that judges it: the member's own check can say
+ *  nothing more of it, so asking that check again brings no verdict that names a trunk (novox/hq issue 1106). */
+export const WAITS_FOR_COMPOSED = "waits for its group's composed check";
+
 /** The forge's status for the gate. */
 export function statusFor(c: Checked): CommitStatus {
   const gate = c.gate ?? { verdict: c.verdict, summary: c.summary };
@@ -260,7 +264,7 @@ export function statusesFor(c: Checked, facts: RepoCheckFacts = {}, gateNow?: st
     // set. The gate stays pending, saying it waits for the group, unless a composed verdict already stands on it.
     const out: CommitStatus[] = [];
     if (!(gateNow ?? "").includes(" composed: ")) {
-      out.push({ state: "pending", context: CHECK_CONTEXT, description: "waits for its group's composed check" });
+      out.push({ state: "pending", context: CHECK_CONTEXT, description: WAITS_FOR_COMPOSED });
     }
     const repo = c["repo-check"];
     if (repo) out.push(judgedFirst(c, repoStatus(repo, facts)));

modules/gitea/test/bind.test.ts

@@ -0,0 +1,58 @@
+// **A consumer that cannot be bound yet is bound again** (novox/hq issue 1793): the runtime's "no responders" at the
+// bundle's start, seen 2026-10-22 00:28:37 on mesh-catalog#427's verdict, ended the bundle and the verdict was never
+// written on the forge.
+
+import { test } from "node:test";
+import assert from "node:assert/strict";
+
+import { bindInBackground, bindUntilHeld, bindWait } from "../dist/bind.js";
+
+test("a bind refused with no responders is asked again until it holds, and says so", async () => {
+  let calls = 0;
+  const waits: number[] = [];
+  const said: string[] = [];
+  await bindUntilHeld("mesh-controller.checked", async () => {
+    calls++;
+    if (calls < 4) throw new Error("binding gitea's consumer novox_gitea: nats: no responders available for request");
+  }, async (ms) => { waits.push(ms); }, (l) => said.push(l));
+  assert.equal(calls, 4);
+  assert.deepEqual(waits, [2_000, 5_000, 10_000]);
+  assert.equal(said.length, 4);
+  assert.match(said[0], /no responders available for request.*asking again in 2s/);
+  assert.match(said[3], /is bound after 4 attempts/);
+});
+
+test("a bind that holds the first time says nothing and waits for nothing", async () => {
+  const said: string[] = [];
+  await bindUntilHeld("x", async () => {}, async () => assert.fail("waited"), (l) => said.push(l));
+  assert.deepEqual(said, []);
+});
+
+test("the wait grows to 30 s and stays", () => {
+  assert.deepEqual([1, 2, 3, 4, 50].map(bindWait), [2_000, 5_000, 10_000, 30_000, 30_000]);
+});
+
+test("the binds start without being waited for: the caller returns while a bind keeps refusing, and they go in order", async () => {
+  const order: string[] = [];
+  let finished = false;
+  let refusals = 0;
+  const gate = new Promise<void>((r) => setTimeout(r, 0));
+  bindInBackground([
+    ["first", async () => { refusals++; if (refusals < 3) throw new Error("nats: no responders available for request"); order.push("first"); }],
+    ["second", async () => { order.push("second"); }],
+  ], () => { finished = true; }, async () => { await gate; }, () => {});
+  // Returned at once, with the first bind refused and nothing done.
+  assert.equal(finished, false);
+  assert.deepEqual(order, []);
+  await new Promise((r) => setTimeout(r, 20));
+  assert.deepEqual(order, ["first", "second"]);
+  assert.equal(finished, true);
+});
+
+test("a bind that never holds does not stop the caller from returning", () => {
+  let returned = false;
+  bindInBackground([["x", async () => { throw new Error("no responders"); }]], () => assert.fail("done"),
+    () => new Promise(() => {}), () => {});
+  returned = true;
+  assert.equal(returned, true);
+});

modules/gitea/test/bundle-import.test.ts

@@ -0,0 +1,38 @@
+// **The bundle's import ends while a bind is refused** (novox/hq issue 1793). The launcher imports index.js and then answers
+// node-tools' handshake, which has 10 s before the bundle is killed and never started again. A bind awaited at the top
+// of index.ts, refused for longer, ended the bundle at 00:28:37 on 2026-10-22. Run in a child: the polls' timers keep a
+// process alive, and the child says "imported" and exits as soon as the import resolves.
+
+import { test } from "node:test";
+import assert from "node:assert/strict";
+import { spawn } from "node:child_process";
+import { dirname, join } from "node:path";
+import { fileURLToPath, pathToFileURL } from "node:url";
+
+const here = dirname(fileURLToPath(import.meta.url));
+
+test("importing the bundle resolves while the broker keeps refusing the binds", async () => {
+  const index = pathToFileURL(join(here, "..", "dist", "index.js")).href;
+  const script = `
+    const { useBroker } = await import("@novox/mesh-sdk/messaging");
+    useBroker(() => ({
+      subscribe: async () => { throw new Error("binding gitea's consumer novox_gitea: nats: no responders available for request"); },
+      publish: async () => {}, request: async () => { throw new Error("no responders"); },
+      handle: async () => () => {}, close: async () => {},
+    }));
+    await import(${JSON.stringify(index)});
+    console.log("imported");
+    process.exit(0);`;
+  const env = { ...process.env, MESH_GITEA_TOKEN: "x", MESH_GITEA_URL: "http://127.0.0.1:1" };
+  for (const k of ["MESH_GITEA_STATE_DIR", "MESH_GITEA_ADMIN_USER", "MESH_GITEA_ADMIN_PASSWORD", "MESH_SERVED_MODULE"]) delete env[k];
+  const child = spawn(process.execPath, ["--input-type=module", "-e", script], { cwd: join(here, ".."), env, stdio: ["ignore", "pipe", "pipe"] });
+  let out = "";
+  let err = "";
+  child.stdout.on("data", (d) => (out += d));
+  child.stderr.on("data", (d) => (err += d));
+  const ended = new Promise<void>((r) => child.on("exit", () => r()));
+  const timer = setTimeout(() => child.kill("SIGKILL"), 3000);
+  await ended;
+  clearTimeout(timer);
+  assert.match(out, /imported/, `the import did not resolve within 3 s while a bind was refused; stderr: ${err.slice(0, 600)}`);
+});

modules/gitea/test/guard.test.ts

@@ -339,6 +339,30 @@ test("gitea_merge_pull_request refuses a verdict judged against an earlier trunk
   assert.equal(state.emitted.length, 4, "a merge asks no check");
 });
 
+// **A group member whose gate waits for its group's composed check is not announced again by the merge tool** (novox/hq issue
+// 1106): the member's own check can only say "composed" again, so each refusal's ask brought a verdict that names no trunk and
+// the next merge was refused the same way, for ever. The tool says whose verdict is awaited and asks nothing.
+test("gitea_merge_pull_request asks no check of a member that waits for its group's composed check", async () => {
+  const merge = () => tool("gitea_merge_pull_request").run({ owner: "novox", repo: "mesh-catalog", number: 7, head: REVIEWED });
+  state.trunk = TRUNK;
+  const before = state.emitted.length;
+  state.statuses = [{ context: "mesh/merge-gate", state: "pending", description: "waits for its group's composed check" },
+    { context: "mesh/repo-check", state: "success", description: "pass: y" }];
+  for (let i = 0; i < 3; i++) {
+    await assert.rejects(merge(), (err: Error) => {
+      assert.match(err.message, /waits for its group's composed check/);
+      assert.match(err.message, /mesh-delivery asks it, this tool asks no check/);
+      assert.match(err.message, /Nothing was merged/);
+      return true;
+    });
+  }
+  assert.equal(state.emitted.length, before, "no check is announced again and again");
+  assert.equal(state.merged, false);
+  // Once the composed verdict names the member's unmoved trunk, it merges.
+  state.statuses = judgedAt(TRUNK);
+  assert.equal(((await merge()) as Record<string, unknown>).merged, true);
+});
+
 // A merge lands only the head that was reviewed (novox/hq issue 381): mesh-controller#197 was reviewed at one head,
 // force-pushed, checked green at the new one, and merged there, because the tool merged whatever the head was.
 test("gitea_merge_pull_request merges only the head it is named, and refuses one that is not the head", async () => {

modules/gitea/trunk.ts

@@ -17,7 +17,7 @@
 import { existsSync, mkdirSync, readFileSync, renameSync, writeFileSync } from "node:fs";
 import { dirname } from "node:path";
 import type { CommitStatus, GiteaClient, GiteaPull, HeadCheck } from "./client.js";
-import { CHECK_CONTEXT, REPO_CHECK_CONTEXT } from "./pulls.js";
+import { CHECK_CONTEXT, REPO_CHECK_CONTEXT, WAITS_FOR_COMPOSED } from "./pulls.js";
 
 /** A commit as a verdict names it: its first twelve characters. */
 export function twelve(sha: string | undefined): string {
@@ -58,6 +58,11 @@ export function checkOnItsWay(gate: HeadCheck | undefined): boolean {
   return d.startsWith("waiting in the build queue") || d.startsWith("building on ") || d.startsWith("checking again");
 }
 
+/** Whether a gate says it waits for its group's composed check. */
+export function waitsForComposed(gate: HeadCheck | undefined): boolean {
+  return !!gate && gate.state === "pending" && (gate.description ?? "").startsWith(WAITS_FOR_COMPOSED);
+}
+
 /**
  * The statuses a trunk's move puts back to pending on one open pull request's head, from what the forge holds on it
  * now: none when it has no merge check yet, when a check is pending (on its way, or already out of date — its

modules/kernel/README.md

@@ -1,8 +1,9 @@
 # kernel
 
-The kernel's run-time settings on a machine (novox/hq to-be 42 Phase 1, row 11). Today it holds one:
+The kernel's run-time settings on a machine (novox/hq to-be 42 Phase 1, row 11). It holds two things:
-**transparent huge pages**, set per machine. The rest of the row (the kernel package, microcode, boot
+**transparent huge pages**, set per machine, and **the fallback kernel** (`linux-lts` with its headers) and
-entries) is not built yet.
+its place on the boot menu (novox/hq ADR 0508 §9 and §10). The default kernel's package, and microcode, are
+not built yet.
 
 ## Why (novox/hq issue 746)
 
@@ -35,16 +36,34 @@ under the new mode. A failed rotation is said in the unit's journal and does not
 rotation is made while the machine is still starting (`systemctl is-system-running` says `initializing`
 or `starting`): nothing is in huge pages yet, and the persistent journal opens after this unit.
 
+## The fallback kernel (novox/hq ADR 0508, issue 1841)
+
+Every machine keeps a second, older kernel to start from, so a kernel upgrade that does not boot is not the
+end of the machine. The module declares the packages `linux-lts` and `linux-lts-headers` (so every DKMS module is
+built for the fallback kernel too) after its boot-entries service, so the entry is in place before the kernel is.
+
+| | what | notes |
+|---|---|---|
+| file | `${dir:state}/boot-entries` | the script. It reads from the machine which loader booted it: the EFI variable `LoaderEntrySelected` present means systemd-boot, a `/boot/grub/grub.cfg` without it means GRUB, neither fails the unit loudly |
+| | systemd-boot | writes `/boot/loader/entries/mesh-linux-lts.conf` from `/proc/cmdline` without `initrd=` and `BOOT_IMAGE=`, with the microcode images present in `/boot` and the fallback initramfs as initrd lines; `loader.conf` and the default entry are never touched |
+| | GRUB | runs `grub-mkconfig -o /boot/grub/grub.cfg` only when the set of `/boot/vmlinuz-*` differs from the kernels the menu names, with `GRUB_TOP_LEVEL` naming the kernel the machine booted (`BOOT_IMAGE`; else the non-fallback kernel), since GRUB lists kernels in reverse version order and would otherwise make the fallback kernel the default; `/etc/default/grub` still overrides it when it sets one |
+| | room | while `/boot/vmlinuz-linux-lts` is not there yet, less than 96 MiB free on `/boot` fails the unit and says so (the fallback kernel writes about 72 MB, issue 1836) |
+| | a kernel-copying hook | a hook in `/etc/pacman.d/hooks` that the mesh did not write, triggered by kernel images and copying to one fixed file name in `/boot`, would put the fallback kernel in the default kernel's place: it is moved into `${dir:state}/taken-over/` and named in the unit's journal. Each kernel is then placed under its own package's name by the distribution's hooks |
+| file | `/etc/systemd/system/mesh-kernel-boot-entries.service` | oneshot, sandboxed: the file system read-only but for `/boot`, `/etc/pacman.d/hooks` and the module's state; no home, no network |
+| file | `/etc/pacman.d/hooks/90-mesh-kernel-boot-entries.hook` | runs the script after a kernel image is installed, upgraded or removed |
+| packages | `linux-lts`, `linux-lts-headers` | declared after the service and the hook |
+
 ## Tools
 
 | tool | | answers |
 |---|---|---|
+| `kernel_boot` | r | the loader (`systemd-boot`, `grub` or `none`), the menu's entries, the kernels in `/boot`, the entry booted (systemd-boot) or the kernel image booted (GRUB), whether the fallback kernel is on the menu with its kernel in `/boot`, and the room free on `/boot` in KiB |
 | `kernel_huge_pages` | r | the mode, defrag and shared-memory mode; each per-size control and what `inherit` resolves to; huge pages by kind from `/proc/meminfo` (MiB); the units holding the most file pages in huge folios (`memory.stat` `file_thp`) with their dirty and writeback bytes, khugepaged's collapses and the bytes their cgroup wrote (`io.stat`, the most any one device saw: a mirror and its members each count the same write) |
 
 ## Tests
 
 `go test ./...`: the tool over a stand-in tree holding the control node's own files of 2026-10-14; the
-manifest's shape (the default, the order, the unit and its sandbox, reload, restart and health); and the script as the mesh
+manifest's shape (the default, the order, the unit and its sandbox, reload, restart and health); the boot-entries script run with `sh` over stand-in roots (a systemd-boot entries directory, a GRUB menu, a hook that copies kernels to one fixed name): the entry from the booted command line, a menu generated again only when the kernels changed, no loader, no room, the taken-over hook; `kernel_boot` over the same roots; and the huge-pages script as the mesh
 writes it, run with `sh` against a stand-in directory: it sets and reads back, keeps what it found once,
 rotates the journal once and not for `always` nor while the machine starts, goes straight to a new value on a
 reload without rewriting what it found, gives back what it found and then keeps nothing, refuses a value the kernel

modules/kernel/cmd/kernel-tools/boot.go

@@ -0,0 +1,89 @@
+package main
+
+// kernel_boot: which loader booted the machine, its entries, the kernels in /boot, the entry it booted and
+// whether the fallback kernel is on the menu (novox/hq ADR 0508 §9, issue 1841). Reads only.
+
+import (
+	"os"
+	"path/filepath"
+	"regexp"
+	"sort"
+	"strings"
+	"syscall"
+	"unicode/utf16"
+)
+
+const loaderSelected = "sys/firmware/efi/efivars/LoaderEntrySelected-4a67b082-0a4c-41cf-b6c7-440b29bb8c4f"
+
+// BootState is what kernel_boot answers.
+type BootState struct {
+	Loader          string   `json:"loader"`
+	Entries         []string `json:"entries"`
+	Kernels         []string `json:"kernels"`
+	Booted          string   `json:"booted"`
+	FallbackPresent bool     `json:"fallback_present"`
+	BootFreeKiB     int64    `json:"boot_free_kib"`
+}
+
+var grubKernel = regexp.MustCompile(`(?m)^\s*linux\s+(?:/boot)?/(vmlinuz-\S+)`)
+var grubTitle = regexp.MustCompile(`(?m)^\s*menuentry\s+'([^']*)'`)
+var bootImage = regexp.MustCompile(`BOOT_IMAGE=(?:/boot)?/?(\S+)`)
+
+// Boot reads the machine, the loader the way the boot-entries script does: the loader's EFI variable means
+// systemd-boot, a grub.cfg without it GRUB.
+func (m *Machine) Boot() (*BootState, error) {
+	b := &BootState{Loader: "none", Entries: []string{}, Kernels: []string{}}
+	files, _ := filepath.Glob(m.path("boot/vmlinuz-*"))
+	for _, f := range files {
+		b.Kernels = append(b.Kernels, filepath.Base(f))
+	}
+	sort.Strings(b.Kernels)
+	hasKernel := func(name string) bool {
+		for _, k := range b.Kernels {
+			if k == name {
+				return true
+			}
+		}
+		return false
+	}
+	var s syscall.Statfs_t
+	if err := syscall.Statfs(m.path("boot"), &s); err == nil {
+		b.BootFreeKiB = int64(s.Bavail) * int64(s.Bsize) / 1024
+	}
+	if raw, err := os.ReadFile(m.path(loaderSelected)); err == nil {
+		b.Loader = "systemd-boot"
+		if len(raw) > 4 {
+			var u []uint16
+			for i := 4; i+1 < len(raw); i += 2 {
+				u = append(u, uint16(raw[i])|uint16(raw[i+1])<<8)
+			}
+			b.Booted = strings.TrimRight(string(utf16.Decode(u)), "\x00")
+		}
+		files, _ := filepath.Glob(m.path("boot/loader/entries/*.conf"))
+		for _, f := range files {
+			b.Entries = append(b.Entries, filepath.Base(f))
+		}
+		sort.Strings(b.Entries)
+		if raw, err := os.ReadFile(m.path("boot/loader/entries/mesh-linux-lts.conf")); err == nil {
+			b.FallbackPresent = strings.Contains(string(raw), "/vmlinuz-linux-lts") && hasKernel("vmlinuz-linux-lts")
+		}
+		return b, nil
+	}
+	if raw, err := os.ReadFile(m.path("boot/grub/grub.cfg")); err == nil {
+		b.Loader = "grub"
+		for _, t := range grubTitle.FindAllStringSubmatch(string(raw), -1) {
+			b.Entries = append(b.Entries, t[1])
+		}
+		for _, k := range grubKernel.FindAllStringSubmatch(string(raw), -1) {
+			if k[1] == "vmlinuz-linux-lts" && hasKernel("vmlinuz-linux-lts") {
+				b.FallbackPresent = true
+			}
+		}
+		if cmd, err := m.read("proc/cmdline"); err == nil {
+			if i := bootImage.FindStringSubmatch(cmd); i != nil {
+				b.Booted = i[1]
+			}
+		}
+	}
+	return b, nil
+}

modules/kernel/cmd/kernel-tools/boot_test.go

@@ -0,0 +1,90 @@
+package main
+
+// kernel_boot over stand-in roots: a systemd-boot machine with and without the fallback entry, a GRUB machine
+// with and without the fallback kernel in its menu, and a machine with neither (novox/hq ADR 0508 §9, issue 1841).
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+const selectedVar = "sys/firmware/efi/efivars/LoaderEntrySelected-4a67b082-0a4c-41cf-b6c7-440b29bb8c4f"
+
+func put(t *testing.T, root, p, content string) {
+	t.Helper()
+	full := filepath.Join(root, p)
+	if err := os.MkdirAll(filepath.Dir(full), 0o755); err != nil {
+		t.Fatal(err)
+	}
+	write(t, full, content, 0o644)
+}
+
+func bootOf(t *testing.T, root string) *BootState {
+	t.Helper()
+	got, err := (&Machine{Root: root}).Boot()
+	if err != nil {
+		t.Fatal(err)
+	}
+	return got
+}
+
+func TestKernelBootReadsASystemdBootMachineWithItsFallbackEntry(t *testing.T) {
+	root := t.TempDir()
+	put(t, root, selectedVar, "\x07\x00\x00\x00a\x00r\x00c\x00h\x00.\x00c\x00o\x00n\x00f\x00\x00\x00")
+	put(t, root, "boot/loader/entries/arch.conf", defaultEntry)
+	put(t, root, "boot/loader/entries/mesh-linux-lts.conf", "title Arch Linux (linux-lts, fallback)\nlinux /vmlinuz-linux-lts\n")
+	put(t, root, "boot/vmlinuz-linux", "k")
+	put(t, root, "boot/vmlinuz-linux-lts", "k")
+	got := bootOf(t, root)
+	if got.Loader != "systemd-boot" || got.Booted != "arch.conf" || !got.FallbackPresent {
+		t.Fatalf("%+v", got)
+	}
+	if len(got.Entries) != 2 || got.Entries[0] != "arch.conf" || got.Entries[1] != "mesh-linux-lts.conf" {
+		t.Fatalf("entries: %v", got.Entries)
+	}
+	if len(got.Kernels) != 2 || got.Kernels[0] != "vmlinuz-linux" || got.Kernels[1] != "vmlinuz-linux-lts" {
+		t.Fatalf("kernels: %v", got.Kernels)
+	}
+	if got.BootFreeKiB <= 0 {
+		t.Fatalf("free: %d", got.BootFreeKiB)
+	}
+}
+
+func TestKernelBootSaysASystemdBootMachineHasNoFallbackYet(t *testing.T) {
+	root := t.TempDir()
+	put(t, root, selectedVar, "\x07\x00\x00\x00a\x00r\x00c\x00h\x00.\x00c\x00o\x00n\x00f\x00\x00\x00")
+	put(t, root, "boot/loader/entries/arch.conf", defaultEntry)
+	put(t, root, "boot/vmlinuz-linux", "k")
+	// The entry file alone is not the fallback: the kernel it names must be in /boot.
+	put(t, root, "boot/loader/entries/mesh-linux-lts.conf", "linux /vmlinuz-linux-lts\n")
+	if got := bootOf(t, root); got.FallbackPresent {
+		t.Fatalf("a fallback entry without its kernel: %+v", got)
+	}
+}
+
+func TestKernelBootReadsAGrubMachine(t *testing.T) {
+	root := t.TempDir()
+	put(t, root, "boot/grub/grub.cfg", grubMenu)
+	put(t, root, "boot/vmlinuz-linux", "k")
+	put(t, root, "proc/cmdline", bootedCmdline)
+	got := bootOf(t, root)
+	if got.Loader != "grub" || got.FallbackPresent || got.Booted != "vmlinuz-linux" {
+		t.Fatalf("%+v", got)
+	}
+	if len(got.Entries) != 2 || got.Entries[0] != "Arch Linux" {
+		t.Fatalf("entries: %v", got.Entries)
+	}
+	put(t, root, "boot/vmlinuz-linux-lts", "k")
+	put(t, root, "boot/grub/grub.cfg", grubMenu+"menuentry 'Arch Linux LTS' {\n\tlinux\t/boot/vmlinuz-linux-lts root=x rw\n}\n")
+	if got := bootOf(t, root); !got.FallbackPresent {
+		t.Fatalf("%+v", got)
+	}
+}
+
+func TestKernelBootSaysWhenThereIsNoLoader(t *testing.T) {
+	got := bootOf(t, t.TempDir())
+	if got.Loader != "none" || got.FallbackPresent || len(got.Entries) != 0 {
+		t.Fatalf("%+v", got)
+	}
+}

modules/kernel/cmd/kernel-tools/bootentries_test.go

@@ -0,0 +1,284 @@
+package main
+
+// The boot-entries script as the mesh writes it, run with sh over a stand-in root (novox/hq ADR 0508 §9 and
+// §10, issue 1841). The fixtures are the shapes read from machines: a systemd-boot entries directory, a GRUB
+// menu, a hook that copies every kernel image to the default kernel's name, and the command line a machine
+// booted with.
+
+import (
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+const bootedCmdline = "initrd=\\initramfs-linux.img BOOT_IMAGE=/vmlinuz-linux root=UUID=2f6c1e0a-5c0e-4d52-9a57-1d8a2a7a3c11 rw quiet loglevel=3 initrd=\\intel-ucode.img\n"
+
+const defaultEntry = "title Arch Linux\nlinux /vmlinuz-linux\ninitrd /intel-ucode.img\ninitrd /initramfs-linux.img\noptions root=UUID=2f6c1e0a-5c0e-4d52-9a57-1d8a2a7a3c11 rw quiet\n"
+
+const loaderConf = "default arch.conf\ntimeout 3\nconsole-mode max\n"
+
+// grubMenu is the part of a generated grub.cfg that names kernels, for a machine holding one kernel.
+const grubMenu = `menuentry 'Arch Linux' --class arch {
+	set root='hd0,gpt2'
+	linux	/boot/vmlinuz-linux root=UUID=2f6c1e0a-5c0e-4d52-9a57-1d8a2a7a3c11 rw quiet
+	initrd	/boot/initramfs-linux.img
+}
+menuentry 'Arch Linux, with fallback initramfs' --class arch {
+	linux	/boot/vmlinuz-linux root=UUID=2f6c1e0a-5c0e-4d52-9a57-1d8a2a7a3c11 rw quiet
+	initrd	/boot/initramfs-linux-fallback.img
+}
+`
+
+// kernelCopyingHook copies every installed kernel image to the default kernel's name on the boot partition.
+const kernelCopyingHook = `[Trigger]
+Operation = Install
+Operation = Upgrade
+Type = Path
+Target = usr/lib/modules/*/vmlinuz
+
+[Action]
+Description = Copying the kernel to the default name
+When = PostTransaction
+Exec = /usr/bin/sh -c '/usr/bin/cp /usr/lib/modules/$(uname -r)/vmlinuz /boot/vmlinuz-linux'
+`
+
+// otherHook is a hook of the distribution's shape that has nothing to do with kernel images.
+const otherHook = `[Trigger]
+Operation = Upgrade
+Type = Package
+Target = pacman-mirrorlist
+
+[Action]
+Description = Updating the mirror list
+When = PostTransaction
+Exec = /usr/bin/cp /etc/pacman.d/mirrorlist.pacnew /etc/pacman.d/mirrorlist
+`
+
+type bootBed struct {
+	script, root, state, bin, mkconfig string
+	need                               string
+}
+
+func newBootBed(t *testing.T) bootBed {
+	t.Helper()
+	dir := t.TempDir()
+	b := bootBed{script: filepath.Join(dir, "boot-entries"), root: filepath.Join(dir, "root"), state: filepath.Join(dir, "state"),
+		bin: filepath.Join(dir, "bin"), mkconfig: filepath.Join(dir, "mkconfig")}
+	content := manifest(t).resource(t, "boot-entries").text(t)
+	content = strings.ReplaceAll(content, "${dir:state}", b.state)
+	if strings.Contains(content, "${") {
+		t.Fatalf("a substitution the test does not make is left in the script")
+	}
+	for _, d := range []string{b.root + "/boot", b.root + "/proc", b.root + "/etc/pacman.d/hooks", b.state, b.bin} {
+		if err := os.MkdirAll(d, 0o755); err != nil {
+			t.Fatal(err)
+		}
+	}
+	write(t, b.script, content, 0o755)
+	write(t, b.root+"/proc/cmdline", bootedCmdline, 0o644)
+	// the stand-in grub-mkconfig records the kernel it was told to put first, then its arguments.
+	write(t, filepath.Join(b.bin, "grub-mkconfig"), "#!/bin/sh\necho \"top=$GRUB_TOP_LEVEL $@\" >>"+b.mkconfig+"\n", 0o755)
+	return b
+}
+
+func (b bootBed) put(t *testing.T, p, content string) {
+	t.Helper()
+	full := filepath.Join(b.root, p)
+	if err := os.MkdirAll(filepath.Dir(full), 0o755); err != nil {
+		t.Fatal(err)
+	}
+	write(t, full, content, 0o644)
+}
+
+func (b bootBed) systemdBoot(t *testing.T) {
+	b.put(t, "sys/firmware/efi/efivars/LoaderEntrySelected-4a67b082-0a4c-41cf-b6c7-440b29bb8c4f", "\x07\x00\x00\x00a\x00r\x00c\x00h\x00.\x00c\x00o\x00n\x00f\x00\x00\x00")
+	b.put(t, "boot/loader/loader.conf", loaderConf)
+	b.put(t, "boot/loader/entries/arch.conf", defaultEntry)
+	b.put(t, "boot/vmlinuz-linux", "k")
+}
+
+func (b bootBed) run(t *testing.T) (string, error) {
+	t.Helper()
+	args := []string{b.script, "run", b.root, b.state}
+	if b.need != "" {
+		args = append(args, b.need)
+	}
+	cmd := exec.Command("sh", args...)
+	cmd.Env = append(os.Environ(), "PATH="+b.bin+string(os.PathListSeparator)+os.Getenv("PATH"))
+	out, err := cmd.CombinedOutput()
+	return string(out), err
+}
+
+func (b bootBed) read(t *testing.T, p string) string {
+	t.Helper()
+	raw, _ := os.ReadFile(filepath.Join(b.root, p))
+	return string(raw)
+}
+
+func TestASystemdBootMachineGetsTheFallbackEntryFromItsBootedCommandLine(t *testing.T) {
+	b := newBootBed(t)
+	b.systemdBoot(t)
+	b.put(t, "boot/intel-ucode.img", "u")
+	out, err := b.run(t)
+	if err != nil || !strings.Contains(out, "wrote") {
+		t.Fatalf("%v %s", err, out)
+	}
+	want := "title Arch Linux (linux-lts, fallback)\nlinux /vmlinuz-linux-lts\ninitrd /intel-ucode.img\ninitrd /initramfs-linux-lts.img\n" +
+		"options root=UUID=2f6c1e0a-5c0e-4d52-9a57-1d8a2a7a3c11 rw quiet loglevel=3\n"
+	if got := b.read(t, "boot/loader/entries/mesh-linux-lts.conf"); got != want {
+		t.Fatalf("entry:\n%s\nwant:\n%s", got, want)
+	}
+	// The default entry and the loader's own file are as they were.
+	if b.read(t, "boot/loader/entries/arch.conf") != defaultEntry || b.read(t, "boot/loader/loader.conf") != loaderConf {
+		t.Fatalf("the default entry or loader.conf was touched")
+	}
+	if out, err := b.run(t); err != nil || !strings.Contains(out, "as it was") {
+		t.Fatalf("again: %v %s", err, out)
+	}
+}
+
+func TestWithoutMicrocodeThereIsNoMicrocodeLine(t *testing.T) {
+	b := newBootBed(t)
+	b.systemdBoot(t)
+	if out, err := b.run(t); err != nil {
+		t.Fatalf("%v %s", err, out)
+	}
+	if got := b.read(t, "boot/loader/entries/mesh-linux-lts.conf"); strings.Contains(got, "ucode") || !strings.Contains(got, "initrd /initramfs-linux-lts.img") {
+		t.Fatalf("entry: %s", got)
+	}
+}
+
+func TestAGrubMachineIsGeneratedAgainOnlyWhenItsKernelsChanged(t *testing.T) {
+	b := newBootBed(t)
+	b.put(t, "boot/grub/grub.cfg", grubMenu)
+	b.put(t, "boot/vmlinuz-linux", "k")
+	if out, err := b.run(t); err != nil || !strings.Contains(out, "left as it is") {
+		t.Fatalf("same: %v %s", err, out)
+	}
+	if _, err := os.Stat(b.mkconfig); err == nil {
+		t.Fatalf("the menu was generated again with the same kernels")
+	}
+	b.put(t, "boot/vmlinuz-linux-lts", "k")
+	if out, err := b.run(t); err != nil || !strings.Contains(out, "generated again") {
+		t.Fatalf("changed: %v %s", err, out)
+	}
+	raw, _ := os.ReadFile(b.mkconfig)
+	if string(raw) != "top=/boot/vmlinuz-linux -o "+filepath.Join(b.root, "boot/grub/grub.cfg")+"\n" {
+		t.Fatalf("grub-mkconfig was asked %q", raw)
+	}
+}
+
+// ADR 0508 §9: GRUB's menu lists kernels in reverse version order, so linux-lts would come first and become the
+// default entry (GRUB_DEFAULT=0); the kernel the machine booted is put first, and the fallback kernel never.
+func TestGrubKeepsTheBootedKernelFirstAndNeverTheFallback(t *testing.T) {
+	for name, c := range map[string]struct{ cmdline, want string }{
+		"booted from the default kernel":  {"BOOT_IMAGE=/vmlinuz-linux root=UUID=x rw\n", "top=/boot/vmlinuz-linux"},
+		"booted from a grub device path":  {"BOOT_IMAGE=(hd0,msdos1)/vmlinuz-linux-zen root=UUID=x rw\n", "top=/boot/vmlinuz-linux-zen"},
+		"booted from the fallback kernel": {"BOOT_IMAGE=/vmlinuz-linux-lts root=UUID=x rw\n", "top=/boot/vmlinuz-linux"},
+		"no image on the command line":    {"root=UUID=x rw\n", "top=/boot/vmlinuz-linux"},
+		"an image no longer in /boot":     {"BOOT_IMAGE=/vmlinuz-linux-gone root=UUID=x rw\n", "top=/boot/vmlinuz-linux"},
+	} {
+		b := newBootBed(t)
+		b.put(t, "boot/grub/grub.cfg", grubMenu)
+		b.put(t, "proc/cmdline", c.cmdline)
+		for _, k := range []string{"vmlinuz-linux", "vmlinuz-linux-lts", "vmlinuz-linux-zen"} {
+			b.put(t, "boot/"+k, "k")
+		}
+		if out, err := b.run(t); err != nil {
+			t.Fatalf("%s: %v %s", name, err, out)
+		}
+		raw, _ := os.ReadFile(b.mkconfig)
+		if !strings.HasPrefix(string(raw), c.want+" -o ") {
+			t.Errorf("%s: grub-mkconfig was asked %q, want %s first", name, raw, c.want)
+		}
+	}
+}
+
+func TestAMachineWithNoLoaderFailsLoudly(t *testing.T) {
+	b := newBootBed(t)
+	out, err := b.run(t)
+	if err == nil || !strings.Contains(out, "no boot loader found") {
+		t.Fatalf("%v %s", err, out)
+	}
+}
+
+func TestABootPartitionWithoutRoomFailsBeforeAnythingIsWritten(t *testing.T) {
+	b := newBootBed(t)
+	b.systemdBoot(t)
+	b.need = "999999999999"
+	out, err := b.run(t)
+	if err == nil || !strings.Contains(out, "free room there before the kernel is installed") {
+		t.Fatalf("%v %s", err, out)
+	}
+	if b.read(t, "boot/loader/entries/mesh-linux-lts.conf") != "" {
+		t.Fatalf("an entry was written")
+	}
+	// Once the fallback kernel is in place the room is not asked for again.
+	b.put(t, "boot/vmlinuz-linux-lts", "k")
+	if out, err := b.run(t); err != nil {
+		t.Fatalf("%v %s", err, out)
+	}
+}
+
+func TestAHookThatCopiesKernelsToOneFixedNameIsMovedIntoTheStateAndNamed(t *testing.T) {
+	b := newBootBed(t)
+	b.systemdBoot(t)
+	b.put(t, "etc/pacman.d/hooks/60-copy-kernel.hook", kernelCopyingHook)
+	b.put(t, "etc/pacman.d/hooks/70-mirrorlist.hook", otherHook)
+	b.put(t, "etc/pacman.d/hooks/90-mesh-kernel-boot-entries.hook", "[Trigger]\nTarget = usr/lib/modules/*/vmlinuz\n[Action]\nExec = /bin/cp x /boot/y\n")
+	out, err := b.run(t)
+	if err != nil || !strings.Contains(out, "taken over: the pacman hook 60-copy-kernel.hook") {
+		t.Fatalf("%v %s", err, out)
+	}
+	if b.read(t, "etc/pacman.d/hooks/60-copy-kernel.hook") != "" {
+		t.Fatalf("the copying hook is still in the hook directory")
+	}
+	if raw, _ := os.ReadFile(filepath.Join(b.state, "taken-over", "60-copy-kernel.hook")); string(raw) != kernelCopyingHook {
+		t.Fatalf("moved hook: %q", raw)
+	}
+	if b.read(t, "etc/pacman.d/hooks/70-mirrorlist.hook") != otherHook || b.read(t, "etc/pacman.d/hooks/90-mesh-kernel-boot-entries.hook") == "" {
+		t.Fatalf("a hook that copies no kernel was moved")
+	}
+}
+
+func TestTheBootEntriesUnitAndHookAreTheModules(t *testing.T) {
+	m := manifest(t)
+	unit := m.resource(t, "boot-unit").text(t)
+	for _, line := range []string{"Type=oneshot", "RemainAfterExit=yes", "ExecStart=${dir:state}/boot-entries run", "ProtectSystem=strict",
+		"ReadWritePaths=/boot ${dir:state} /etc/pacman.d/hooks", "NoNewPrivileges=yes", "WantedBy=multi-user.target"} {
+		if !strings.Contains(unit, line+"\n") {
+			t.Errorf("the unit lacks %q", line)
+		}
+	}
+	hook := m.resource(t, "boot-hook")
+	text := hook.text(t)
+	if hook["path"] != "/etc/pacman.d/hooks/90-mesh-kernel-boot-entries.hook" || !strings.Contains(text, "Target = usr/lib/modules/*/vmlinuz\n") ||
+		!strings.Contains(text, "When = PostTransaction\n") || !strings.Contains(text, "Exec = ${dir:state}/boot-entries run\n") {
+		t.Fatalf("the hook: %v\n%s", hook["path"], text)
+	}
+	apply := m.resource(t, "boot-apply")
+	if apply["unit"] != "mesh-kernel-boot-entries.service" || apply["state"] != "running" || apply["boot"] != "enabled" {
+		t.Fatalf("apply: %v", apply)
+	}
+}
+
+// The fallback kernel and its headers are declared after the boot-entries service, so the entry is placed
+// before the kernel is installed and every DKMS module is built for it (ADR 0508 §9).
+func TestTheFallbackKernelAndItsHeadersAreDeclaredAfterTheBootEntriesUnit(t *testing.T) {
+	m := manifest(t)
+	at := map[string]int{}
+	for i, r := range m.Resources {
+		at[r["id"].(string)] = i
+	}
+	for id, pkg := range map[string]string{"linux-lts": "linux-lts", "linux-lts-headers": "linux-lts-headers"} {
+		r := m.resource(t, id)
+		if r["type"] != "package" || r["package"] != pkg || r["absent"] == true {
+			t.Errorf("%s: %v", id, r)
+		}
+		if at[id] < at["boot-apply"] || at[id] < at["boot-hook"] {
+			t.Errorf("%s is declared before the boot-entries unit and hook", id)
+		}
+	}
+}

modules/kernel/cmd/kernel-tools/hugepages_test.go

@@ -1,6 +1,6 @@
 package main
 
-// Over a stand-in tree holding novox's own files of 2026-10-14 23:25 (read through node-reads for
+// Over a stand-in tree holding the files of a real machine of 2026-10-14 23:25 (read through node-reads for
 // novox/hq issue 746): the mode, the per-size controls, meminfo's huge page lines, and fail2ban's and
 // journald's memory.stat and io.stat, cut to the lines the tool reads.
 
@@ -26,7 +26,7 @@ func tree(t *testing.T, files map[string]string) *Machine {
 	return &Machine{Root: root}
 }
 
-func novox(t *testing.T) *Machine {
+func capturedMachine(t *testing.T) *Machine {
 	thp := "sys/kernel/mm/transparent_hugepage/"
 	cg := "sys/fs/cgroup/system.slice/"
 	files := map[string]string{
@@ -53,8 +53,8 @@ func novox(t *testing.T) *Machine {
 	return tree(t, files)
 }
 
-func TestNovoxBeforeTheChange(t *testing.T) {
+func TestTheCapturedMachineBeforeTheChange(t *testing.T) {
-	a, err := novox(t).HugePages(10)
+	a, err := capturedMachine(t).HugePages(10)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -86,7 +86,7 @@ func TestNovoxBeforeTheChange(t *testing.T) {
 }
 
 func TestUnitsAreBoundedAndNoneIsSaid(t *testing.T) {
-	a, err := novox(t).HugePages(1)
+	a, err := capturedMachine(t).HugePages(1)
 	if err != nil || len(a.Units) != 1 {
 		t.Fatalf("%v %+v", err, a)
 	}

modules/kernel/cmd/kernel-tools/main.go

@@ -46,5 +46,15 @@ func tools(m *Machine) []stdio.Tool {
 				return m.HugePages(n)
 			},
 		},
+		{
+			Name: "kernel_boot",
+			Description: "How this machine boots and whether the fallback kernel is on its menu (novox/hq ADR 0508 §9): the loader that booted it " +
+				"(systemd-boot, read from the EFI variable it sets, grub, or none), the menu's entries, the kernels in /boot, the entry " +
+				"the machine booted (systemd-boot) or the kernel image it booted (grub), whether the fallback kernel linux-lts is on " +
+				"the menu with its kernel in /boot, and the room free on /boot in KiB (the fallback kernel needs about 72 MB). " +
+				"Replaces ls /boot, bootctl list, reading grub.cfg and df /boot. (r)",
+			Input: schema(map[string]any{}),
+			Run:   func(args map[string]any) (any, error) { return m.Boot() },
+		},
 	}
 }

modules/kernel/cmd/kernel-tools/manifest_test.go

@@ -24,7 +24,7 @@ func TestTheDefaultIsMadviseAndTheUnitFollowsTheSetting(t *testing.T) {
 	for _, r := range m.Resources {
 		ids = append(ids, r["id"].(string))
 	}
-	if strings.Join(ids, " ") != "state huge-pages unit apply" {
+	if strings.Join(ids, " ") != "state huge-pages unit apply boot-entries boot-unit boot-hook boot-apply linux-lts linux-lts-headers" {
 		t.Fatalf("order: %v", ids)
 	}
 	script := m.resource(t, "huge-pages")
@@ -129,7 +129,7 @@ func (b bed) file(t *testing.T, p string) string {
 }
 
 func TestApplySetsTheModeRotatesTheJournalOnceAndRestoreGivesBackWhatWasFound(t *testing.T) {
-	// novox's file on 2026-10-14, read through node-reads.
+	// a real machine's file on 2026-10-14, read through node-reads.
 	b := newBed(t, "madvise", "[always] madvise never\n")
 	out, err := b.run(t, "apply")
 	if err != nil || !strings.Contains(out, "always -> madvise") {

modules/kernel/files/90-mesh-kernel-boot-entries.hook

@@ -0,0 +1,13 @@
+# Module kernel, novox/hq ADR 0508 §9, issue 1841. After a kernel image is installed, upgraded or removed, the
+# fallback kernel's boot entry (or the GRUB menu) is placed again. Written by the mesh; change the module.
+[Trigger]
+Operation = Install
+Operation = Upgrade
+Operation = Remove
+Type = Path
+Target = usr/lib/modules/*/vmlinuz
+
+[Action]
+Description = Placing the fallback kernel on the boot menu
+When = PostTransaction
+Exec = ${dir:state}/boot-entries run

modules/kernel/files/boot-entries.sh

@@ -0,0 +1,133 @@
+#!/bin/sh
+# The fallback kernel's place on this machine's boot menu (module kernel, novox/hq ADR 0508 §9 and §10,
+# issue 1841). Written by the mesh and run as root by mesh-kernel-boot-entries.service at boot and when the
+# module is applied, and by the pacman hook 90-mesh-kernel-boot-entries.hook after a kernel is installed,
+# upgraded or removed. Replaced on every push; change the module, never this file.
+#
+#   boot-entries run [<root> [<this module's state> [<room needed in /boot, KiB>]]]
+#
+# The three are arguments only so the module's tests can run this against a stand-in tree.
+#
+# It reads from the machine which loader booted it, never from a setting:
+#   systemd-boot  the EFI variable LoaderEntrySelected is present: the entry mesh-linux-lts.conf is written
+#                 from the command line the machine booted with.
+#   GRUB          /boot/grub/grub.cfg exists and that variable does not: the menu is generated again, only
+#                 when the set of kernels in /boot differs from the menu's.
+#   neither       it fails loudly. The default entry is never touched.
+# And a pacman hook of someone else's that copies kernel images to one fixed name in /boot is moved into this
+# module's state first (ADR 0508 §10): it would put the fallback kernel in the default kernel's place.
+set -eu
+
+root=/
+state='${dir:state}'
+[ $# -ge 2 ] && root=$(printf '%s' "$2" | sed 's|/$||')
+[ $# -ge 3 ] && state=$3
+boot=$root/boot
+hooks=$root/etc/pacman.d/hooks
+efivar=$root/sys/firmware/efi/efivars/LoaderEntrySelected-4a67b082-0a4c-41cf-b6c7-440b29bb8c4f
+ours=90-mesh-kernel-boot-entries.hook
+# The fallback kernel and its initramfs are about 72 MB in /boot (issue 1836): less room fails the unit
+# before a package writes half of them.
+need_kib=98304
+[ $# -ge 4 ] && need_kib=$4
+
+[ $# -ge 1 ] && [ "$1" = run ] || {
+	echo "usage: boot-entries run [<root> [<state directory> [<KiB needed>]]]" >&2
+	exit 2
+}
+
+# A hook that is not ours, triggered by kernel images, whose action copies to one fixed name in /boot.
+copies_kernels() {
+	grep -Eqi '^[[:space:]]*Target[[:space:]]*=.*(vmlinuz|usr/lib/modules)' "$1" &&
+		grep -Eq '^[[:space:]]*Exec[[:space:]]*=.*(cp|install|ln|rsync)[[:space:]].*/boot/[A-Za-z0-9._+-]+([^A-Za-z0-9._+/%$*-]|$)' "$1"
+}
+
+if [ -d "$hooks" ]; then
+	for hook in "$hooks"/*.hook; do
+		[ -f "$hook" ] || continue
+		[ "$(basename "$hook")" = "$ours" ] && continue
+		copies_kernels "$hook" || continue
+		mkdir -p "$state/taken-over"
+		mv -f "$hook" "$state/taken-over/$(basename "$hook")"
+		echo "taken over: the pacman hook $(basename "$hook") copied kernel images to one fixed name in /boot; moved to $state/taken-over/ so each kernel keeps its own package's name"
+	done
+fi
+
+if [ -e "$efivar" ]; then
+	loader=systemd-boot
+elif [ -f "$boot/grub/grub.cfg" ]; then
+	loader=grub
+else
+	echo "no boot loader found: the machine was not booted by systemd-boot (no LoaderEntrySelected variable) and there is no $boot/grub/grub.cfg; the fallback kernel has no menu to be placed on" >&2
+	exit 1
+fi
+
+# Room first, only while the fallback kernel is not in /boot yet.
+if [ ! -e "$boot/vmlinuz-linux-lts" ]; then
+	free=$(df -Pk "$boot" | awk 'NR==2 {print $4}')
+	[ -n "$free" ] || free=0
+	if [ "$free" -lt "$need_kib" ]; then
+		echo "$boot has $free KiB free and the fallback kernel needs $need_kib KiB: free room there before the kernel is installed" >&2
+		exit 1
+	fi
+fi
+
+case "$loader" in
+systemd-boot)
+	entries=$boot/loader/entries
+	cmdline=$(sed -e 's/BOOT_IMAGE=[^ ]*//g' -e 's/initrd=[^ ]*//g' "$root/proc/cmdline" | tr -s ' \n' ' ' | sed -e 's/^ //' -e 's/ $//')
+	[ -n "$cmdline" ] || {
+		echo "$root/proc/cmdline holds no command line to boot the fallback kernel with" >&2
+		exit 1
+	}
+	want=$(
+		echo "title Arch Linux (linux-lts, fallback)"
+		echo "linux /vmlinuz-linux-lts"
+		for ucode in intel-ucode.img amd-ucode.img; do
+			[ -e "$boot/$ucode" ] && echo "initrd /$ucode"
+		done
+		echo "initrd /initramfs-linux-lts.img"
+		echo "options $cmdline"
+	)
+	mkdir -p "$entries"
+	if [ "$(cat "$entries/mesh-linux-lts.conf" 2>/dev/null || true)" = "$want" ]; then
+		echo "systemd-boot: mesh-linux-lts.conf, as it was"
+	else
+		printf '%s\n' "$want" >"$entries/mesh-linux-lts.conf"
+		echo "systemd-boot: wrote $entries/mesh-linux-lts.conf from the command line the machine booted with; the default entry is as it was"
+	fi
+	;;
+grub)
+	cfg=$boot/grub/grub.cfg
+	menu=$(sed -n 's|^[[:space:]]*linux[[:space:]]*\(/boot\)\{0,1\}/\(vmlinuz-[^[:space:]]*\).*|\2|p' "$cfg" | sort -u)
+	have=$(cd "$boot" && ls -d vmlinuz-* 2>/dev/null | sort -u || true)
+	if [ "$menu" = "$have" ]; then
+		echo "grub: the menu lists the kernels in /boot, left as it is"
+	else
+		# GRUB lists kernels in reverse version order, so the fallback kernel would come first and become the
+		# default entry: the kernel the machine booted is put first (GRUB_TOP_LEVEL; /etc/default/grub still
+		# overrides it when it sets one), the fallback kernel never.
+		top=$(tr ' ' '\n' <"$root/proc/cmdline" | sed -n 's|^BOOT_IMAGE=\(.*\)$|\1|p' | head -n 1)
+		top=$(printf '%s' "$top" | sed 's|.*/||')
+		case "$top" in
+		vmlinuz-linux-lts | "") top= ;;
+		esac
+		[ -n "$top" ] && [ -e "$boot/$top" ] || top=
+		if [ -z "$top" ]; then
+			if [ -e "$boot/vmlinuz-linux" ]; then
+				top=vmlinuz-linux
+			else
+				top=$(printf '%s\n' $have | grep -v '^vmlinuz-linux-lts$' | head -n 1 || true)
+			fi
+		fi
+		if [ -n "$top" ]; then
+			GRUB_TOP_LEVEL=/boot/$top grub-mkconfig -o "$cfg"
+		else
+			grub-mkconfig -o "$cfg"
+		fi
+		first=$top
+		[ -n "$first" ] || first="the menu's own order"
+		echo "grub: the kernels in /boot changed ($(echo $have | tr '\n' ' ')); the menu is generated again with $first first; the default entry is as it was"
+	fi
+	;;
+esac

modules/kernel/files/mesh-kernel-boot-entries.service

@@ -0,0 +1,22 @@
+[Unit]
+Description=The fallback kernel's place on this machine's boot menu
+# Module kernel, novox/hq ADR 0508 §9, issue 1841. Starting this unit reads which loader booted the machine and
+# places the fallback kernel's boot entry (systemd-boot) or generates the menu again (GRUB); it fails, and says
+# why, when there is no loader or the boot partition has no room. The kernel packages are declared after this
+# unit, so the entry is in place before they are installed.
+After=local-fs.target
+Wants=local-fs.target
+
+[Service]
+Type=oneshot
+RemainAfterExit=yes
+ExecStart=${dir:state}/boot-entries run
+# It writes the boot partition, the pacman hook directory and its own state, and nothing else.
+ProtectSystem=strict
+ReadWritePaths=/boot ${dir:state} /etc/pacman.d/hooks
+ProtectHome=yes
+PrivateNetwork=yes
+NoNewPrivileges=yes
+
+[Install]
+WantedBy=multi-user.target

modules/kernel/module.json

@@ -13,7 +13,8 @@
     }
   },
   "tools": [
-    "kernel_huge_pages"
+    "kernel_huge_pages",
+    "kernel_boot"
   ],
   "resources": [
     {
@@ -53,6 +54,52 @@
       "health": {
         "kind": "unit"
       }
+    },
+    {
+      "id": "boot-entries",
+      "type": "file",
+      "path": "${dir:state}/boot-entries",
+      "mode": "0755",
+      "trusted": true,
+      "template": "files/boot-entries.sh"
+    },
+    {
+      "id": "boot-unit",
+      "type": "file",
+      "path": "/etc/systemd/system/mesh-kernel-boot-entries.service",
+      "mode": "0644",
+      "template": "files/mesh-kernel-boot-entries.service"
+    },
+    {
+      "id": "boot-hook",
+      "type": "file",
+      "path": "/etc/pacman.d/hooks/90-mesh-kernel-boot-entries.hook",
+      "mode": "0644",
+      "template": "files/90-mesh-kernel-boot-entries.hook"
+    },
+    {
+      "id": "boot-apply",
+      "type": "service",
+      "unit": "mesh-kernel-boot-entries.service",
+      "state": "running",
+      "boot": "enabled",
+      "restart-on": [
+        "boot-unit",
+        "boot-entries"
+      ],
+      "health": {
+        "kind": "unit"
+      }
+    },
+    {
+      "id": "linux-lts",
+      "type": "package",
+      "package": "linux-lts"
+    },
+    {
+      "id": "linux-lts-headers",
+      "type": "package",
+      "package": "linux-lts-headers"
     }
   ],
   "build": {

modules/mailu/README.md

@@ -16,6 +16,18 @@ installation's are settings on the assignment, `settings set mailu <file>`:
 header from — the address the proxy forwards with. The front's own hostname is the name of its
 `web` route, told to it by the mesh.
 
+## Mail client autoconfiguration
+
+`mailu-automx` answers what mail clients ask for their settings (Thunderbird, Outlook, Apple) for the domains in
+`AMX_MAIL_DOMAINS`, naming the IMAP and SMTP servers and ports of mailu's environment (`AMX_IMAP_ADDRESS`,
+`AMX_IMAP_PORT`, `AMX_SMTP_ADDRESS`, `AMX_SMTP_PORT`). It is `cmd/automx`, a Go program of the standard library
+only in this module's `go.mod` (ADR 0480 clauses 1, 2, 9). It runs in the mirrored alpine image the route proxy's
+`trust` step runs, from the `program-automx` archive mounted read-only at `/opt/mesh`; the container is restarted
+with the archive and with `mailu.env`, which the program reads at each start. It keeps no database. The file the
+Python automx kept in `data-automx` is left where it is on the machine, not deleted by the mesh (ADR 0480
+clause 10). The answers it gave before are the fixtures in `cmd/automx/testdata/captured`, with how they were
+taken (`CAPTURED`) and what the program answers differently (`DIFFERENCES`).
+
 ## Files it does not know
 
 Each directory or archive this module declares says how it treats a file it did not write (ADR 0422, ADR 0416).
@@ -23,7 +35,7 @@ Each directory or archive this module declares says how it treats a file it did
 - `${dir:mesh-state}`: everything in it is the program's; the mesh moves nothing out (ADR 0422 §2).
 - `${dir:state}`: everything in it is the program's; the mesh moves nothing out (ADR 0422 §2).
 - `${dir:grants}`: everything in it is the program's; the mesh moves nothing out (ADR 0422 §2).
-- `${dir:data-automx}`: everything in it is the program's; the mesh moves nothing out (ADR 0422 §2).
+- the archive `program-automx` (`${dir:state}/automx`): everything in it is the program's; the mesh moves nothing out (ADR 0422 §2).
 - `${dir:data-certs}`: everything in it is the program's; the mesh moves nothing out (ADR 0422 §2).
 - `${dir:data-data}`: everything in it is the program's; the mesh moves nothing out (ADR 0422 §2).
 - `${dir:data-dkim}`: everything in it is the program's; the mesh moves nothing out (ADR 0422 §2).

modules/mailu/automx.ts

@@ -1,87 +0,0 @@
-// What the autoconfiguration module (automx2) holds, as stored: its provider, server, domain and server_domain
-// rows, read from its SQLite file inside its container with the sqlite3 program the image carries, opened
-// read-only. Nothing is written and nothing is interpreted: the rows are the evidence for what automx answers
-// to mail clients (novox/hq issue 1630, ADR 0480), and the reason the answer may be empty.
-
-import type { Exec } from "./health.js";
-
-export const AUTOMX_DATABASE = "/data/db.sqlite";
-
-/** The tables read, each with its columns and its ordering. Fixed text: the tool takes no query from its caller. */
-export const AUTOMX_TABLES: Record<string, { columns: string[]; order: string }> = {
-  provider: { columns: ["id", "name", "short_name"], order: "id" },
-  server: { columns: ["id", "prio", "name", "port", "type", "socket_type", "user_name", "authentication"], order: "id" },
-  domain: { columns: ["id", "name", "provider_id", "ldapserver_id"], order: "id" },
-  server_domain: { columns: ["server_id", "domain_id"], order: "domain_id, server_id" },
-};
-
-/**
- * The one statement that reads a table. The sqlite3 in the mailu-automx image does not know `-json` (it answers
- * "sqlite3: Error: unknown option: -json", issue 1630), so each column is printed as `<type>:<hex of its bytes>`, which
- * the oldest sqlite3 prints in its default list mode: no quoting, no separator or newline inside a cell, and a NULL
- * (`null:`) apart from an empty text (`text:`).
- */
-export function selectOf(table: string): string {
-  const t = AUTOMX_TABLES[table];
-  return `SELECT ${t.columns.map((c) => `typeof(${c}) || ':' || hex(${c})`).join(", ")} FROM ${table} ORDER BY ${t.order}`;
-}
-
-export type Row = Record<string, string | number | null>;
-
-export type AutomxRows = {
-  database: string;
-  tables: Record<string, Row[]>;
-  /** servers whose name is empty: the client is told an empty host name for them */
-  empty_names: { id: number; type: string }[];
-  /** tables that could not be read, each with what sqlite3 or docker said on one line */
-  unreadable: Record<string, string>;
-};
-
-/** One cell as selectOf prints it: `<type>:<hex>`; text is the bytes read as UTF-8, a number is read from its text. */
-function cellOf(cell: string): string | number | null {
-  const at = cell.indexOf(":");
-  if (at < 0 || cell.length - at - 1 > 0 && !/^([0-9A-Fa-f]{2})+$/.test(cell.slice(at + 1))) throw new Error(`sqlite3 printed ${JSON.stringify(cell.slice(0, 40))}, not a cell`);
-  const type = cell.slice(0, at);
-  const bytes = Buffer.from(cell.slice(at + 1), "hex").toString("utf8");
-  switch (type) {
-    case "null": return null;
-    case "integer": case "real": return Number(bytes);
-    default: return bytes;
-  }
-}
-
-/** sqlite3 prints one line per row, cells apart by `|`, and nothing at all for a table without rows. */
-export function parseRows(table: string, output: string): Row[] {
-  const columns = AUTOMX_TABLES[table].columns;
-  const rows: Row[] = [];
-  for (const line of output.split("\n")) {
-    if (line.trim() === "") continue;
-    const cells = line.replace(/\r$/, "").split("|");
-    if (cells.length !== columns.length) throw new Error(`sqlite3 printed ${cells.length} cells for ${columns.length} columns`);
-    rows.push(Object.fromEntries(columns.map((c, i) => [c, cellOf(cells[i])])));
-  }
-  return rows;
-}
-
-/** The command that reads one table: read-only, one fixed statement. */
-export function readCommand(table: string): string[] {
-  return ["sqlite3", "-readonly", AUTOMX_DATABASE, selectOf(table)];
-}
-
-/** Read every table; one that fails is said in `unreadable` and does not hide the others. */
-export async function readAutomx(exec: Exec, container: string): Promise<AutomxRows> {
-  const answer: AutomxRows = { database: AUTOMX_DATABASE, tables: {}, empty_names: [], unreadable: {} };
-  for (const table of Object.keys(AUTOMX_TABLES)) {
-    try {
-      answer.tables[table] = parseRows(table, await exec(container, readCommand(table)));
-    } catch (e) {
-      const err = e as { stderr?: string; message?: string };
-      const text = (err?.stderr ?? "").trim() || (err?.message ?? String(e)).trim();
-      answer.unreadable[table] = text.split("\n").map((l) => l.trim()).filter(Boolean)[0] ?? "it failed and said nothing";
-    }
-  }
-  for (const s of answer.tables.server ?? []) {
-    if (String(s.name ?? "").trim() === "") answer.empty_names.push({ id: Number(s.id), type: String(s.type) });
-  }
-  return answer;
-}

modules/mailu/automx/Dockerfile

@@ -1,44 +0,0 @@
-# automx2 — the autoconfig/autodiscover responder, carried by the mailu module as its own
-# artifact: it is a config-baked sidecar of this mail server, not a standalone application
-# (novox/hq ADR 0015 draws that line at applications).
-#
-# The base is named rather than pinned (novox/hq issue 044): declared in module.json's
-# `build.on`. The build context is the module's own directory; every ADD says so.
-ARG PYTHON_BASE
-
-FROM ${PYTHON_BASE}
-RUN apk add --no-cache bash sqlite
-WORKDIR /automx2
-
-ADD automx/files/setupvenv.sh /automx2/setupvenv.sh
-ADD automx/files/start /automx2/start
-ADD automx/files/setup /automx2/setup
-ADD automx/files/setup-db /automx2/setup-db
-ADD automx/files/add-domains /automx2/add-domains
-RUN chmod u+x setupvenv.sh start add-domains setup setup-db
-
-RUN ./setupvenv.sh \
-   && . .venv/bin/activate \
-   && pip install automx2==2021.6
-
-# The launcher `start` expects. In the predecessor's image this wrapper appeared during a build
-# step that never made it into the files this module carries — the image worked and the recipe
-# could not reproduce it. Written here explicitly, verbatim from the proven image, so the build
-# is the whole truth about the image again.
-RUN mkdir -p .venv/scripts && printf '%s\n' \
-   '#!/usr/bin/env bash' \
-   'set -euo pipefail' \
-   '. .venv/bin/activate' \
-   "export FLASK_ENV='production'" \
-   "export FLASK_APP='automx2.server:app'" \
-   'flask "$@"' > .venv/scripts/flask.sh && chmod +x .venv/scripts/flask.sh
-
-ENV AUTOMX2_CONF=/etc/automx2.conf
-ADD automx/files/automx2.conf /etc/automx2.conf
-
-# VOLUME deliberately absent: the anonymous /data volume is exactly what lost db.sqlite on
-# every recreate (measured on novox 2026-08-10). The manifest binds a real directory instead.
-ENTRYPOINT ["/bin/sh"]
-CMD ["./start"]
-
-EXPOSE 4243

modules/mailu/automx/files/add-domains

@@ -1,49 +0,0 @@
-#!/usr/bin/env bash
-set -e
-
-echo "${MAIL_DOMAINS}"
-
-# Split domains into array
-IFS=', ' read -r -a array <<< "${AMX_MAIL_DOMAINS}"
-
-# User configurable section -- START
-PROVIDER_ID=001
-SQL_CMD="";
-
-# Iterate domains resulting from split on second arg
-for element in "${array[@]}"
-do
-  # Set vars
-  DOMAIN=$element
-  PROVIDER_NAME=$DOMAIN
-  PROVIDER_SHORTNAME=$DOMAIN
-
-  # Optional LDAP server
-  #LDAP_SERVER="ldap.${DOMAIN}"
-  # User configurable section -- END
-  s1_id=$((PROVIDER_ID + 1))
-  s2_id=$((PROVIDER_ID + 2))
-  s3_id=$((PROVIDER_ID + 3))
-  dom_id=$((PROVIDER_ID + 4))
-
-  s3_id='NULL'
-
-  SQL_CMD=$(cat <<EOT
-$SQL_CMD
-INSERT INTO provider(id, name, short_name) VALUES(${PROVIDER_ID}, '${PROVIDER_NAME}', '${PROVIDER_SHORTNAME}');
-INSERT INTO server(id, port, type, name, socket_type, user_name, authentication)
-VALUES(${s1_id}, ${AMX_IMAP_PORT}, 'imap', '${AMX_IMAP_SERVER}', 'STARTTLS', '%EMAILADDRESS%', 'password-cleartext');
-INSERT INTO server(id, port, type, name, socket_type, user_name, authentication)
-VALUES(${s2_id}, ${AMX_SMTP_PORT}, 'smtp', '${AMX_SMTP_ADDRESS}', 'STARTTLS', '%EMAILADDRESS%', 'password-cleartext');
-INSERT INTO domain(id, name, provider_id, ldapserver_id) VALUES(${dom_id}, '${DOMAIN}', ${PROVIDER_ID}, ${s3_id});
-INSERT INTO server_domain(server_id, domain_id) VALUES(${s1_id}, ${dom_id});
-INSERT INTO server_domain(server_id, domain_id) VALUES(${s2_id}, ${dom_id});
-EOT
-)
-
-  PROVIDER_ID=$((PROVIDER_ID+10))
-
-done
-
-echo -e ${SQL_CMD}
-echo -e ${SQL_CMD} | sqlite3 /data/db.sqlite

modules/mailu/automx/files/automx2.conf

@@ -1,21 +0,0 @@
-[automx2]
-# A typical production setup would use loglevel = WARNING
-loglevel = WARNING
-# Echo SQL commands into log? Used for debugging.
-db_echo = false
-
-
-# In-memory SQLite database
-# db_uri = sqlite:///:memory:
-
-# SQLite database in a UNIX-like file system
-db_uri = sqlite:////data/db.sqlite
-
-# MySQL database on a remote server. This example does not use an encrypted
-# connection and is therefore *not* recommended for production use.
-#db_uri = mysql://username:password@server.example.com/db
-
-# Number of proxy servers between automx2 and the client (default: 0).
-# If your logs only show 127.0.0.1 or ::1 as the source IP for incoming
-# connections, proxy_count probably needs to be changed.
-proxy_count = 1

modules/mailu/automx/files/setup

@@ -1,12 +0,0 @@
-#!/usr/bin/env bash
-set -e
-
-if [ ! -e /data/db.sqlite ]; then
-  # DB SETUP
-  echo "SETTING UP DB"
-  ./setup-db
-
-  echo "ADDING DOMAINS"
-  # Add the domains
-  ./add-domains
-fi

modules/mailu/automx/files/setup-db

@@ -1,84 +0,0 @@
-#!/usr/bin/env bash
-set -e
-
-# LDAP-Server
-LDAP=$(cat <<EOT
-CREATE TABLE ldapserver(
-  id INT PRIMARY KEY  NOT NULL,
-  name  TEXT NOT NULL,
-  port INT NOT NULL,
-  use_ssl INT NOT NULL,
-  search_base TEXT NOT NULL,
-  search_filter TEXT NOT NULL,
-  attr_uid TEXT NOT NULL,
-  attr_cn TEXT NOT NULL,
-  bind_password TEXT NOT NULL,
-  bind_user TEXT NOT NULL
-);
-EOT
-)
-
-# Provider
-PROVIDER=$(cat <<EOT
-CREATE TABLE provider(
-  id INT PRIMARY KEY  NOT NULL,
-  name  TEXT NOT NULL,
-  short_name TEXT NOT NULL
-);
-EOT
-)
-
-# Server
-SERVER=$(cat <<EOT
-CREATE TABLE server(
-  id INT PRIMARY KEY  NOT NULL,
-  prio INT NOT NULL DEFAULT 10,
-  name  TEXT NOT NULL,
-  port INT NOT NULL,
-  type TEXT NOT NULL,
-  socket_type TEXT NOT NULL,
-  user_name TEXT NOT NULL,
-  authentication TEXT NOT NULL
-);
-EOT
-)
-
-# Domain
-DOMAIN=$(cat <<EOT
-CREATE TABLE domain(
-  id INT PRIMARY KEY  NOT NULL,
-  name  TEXT NOT NULL,
-  provider_id INT NOT NULL,
-  ldapserver_id INT NULL,
-  FOREIGN KEY(ldapserver_id) REFERENCES ldapserver(id),
-  FOREIGN KEY(provider_id) REFERENCES provider(id)
-);
-CREATE UNIQUE INDEX domain_name ON domain(name);
-EOT
-)
-
-# Server-Domain
-SERVER_DOMAIN=$(cat <<EOT
-CREATE TABLE server_domain(
-  server_id INT NOT NULL,
-  domain_id INT NOT NULL,
-  FOREIGN KEY(server_id) REFERENCES server(id),
-  FOREIGN KEY(domain_id) REFERENCES domain(id)
-);
-EOT
-)
-
-## TODO Foreign keys
-
-SQL_CMD=$(cat <<EOT
-$LDAP
-$PROVIDER
-$SERVER
-$DOMAIN
-$SERVER_DOMAIN
-EOT
-)
-
-echo -e ${SQL_CMD}
-
-echo -e ${SQL_CMD} | sqlite3 /data/db.sqlite

modules/mailu/automx/files/setupvenv.sh

@@ -1,38 +0,0 @@
-#!/usr/bin/env bash
-# vim:ts=4:sw=4:noet
-#
-# Creates a Python 3 virtual environment. The target directory can be passed
-# as a parameter. The default path is '.venv' in the current directory.
-
-dir="${1:-.venv}"
-echo "Setup dir $dir"
-
-set -e
-if [ -d "${dir}" ]; then
-	echo >&2 "Directory '${dir}' already exists, exiting."
-	exit 1
-fi
-python3 -m venv "${dir}"
-source "${dir}/bin/activate"
-
-set +e
-pip install -U pip setuptools wheel || true
-
-#set -e
-## vim:tabstop=4:noexpandtab
-##
-## Creates a Python 3 virtual environment. The target directory can be passed
-## as a parameter. The default path is 'venv' in the current directory.
-#
-#dir="${1:-venv}"
-#
-#set -e
-#if [ -d "${dir}" ]; then
-#        echo "Directory '${dir}' already exists, exiting." >&2
-#        exit 1
-#fi
-#python3 -m venv "${dir}"
-#. "${dir}/bin/activate"
-#
-#set +e
-#pip install -U pip setuptools || true

modules/mailu/automx/files/start

@@ -1,8 +0,0 @@
-#!/usr/bin/env bash
-set -e
-
-# Setup
-./setup
-
-# Start
-./.venv/scripts/flask.sh run --host=0.0.0.0 --port=4243

modules/mailu/cmd/automx/automx_test.go

@@ -0,0 +1,260 @@
+package main
+
+import (
+	"bytes"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"os"
+	"path/filepath"
+	"sort"
+	"strconv"
+	"strings"
+	"testing"
+)
+
+// The environment mailu gives automx on novox when the fixtures were captured (files/mailu.env): the mail domain,
+// the route name for both servers, the ports.
+var capturedEnvironment = map[string]string{
+	"AMX_MAIL_DOMAINS": "novox.be",
+	"AMX_IMAP_ADDRESS": "mail.novox.be",
+	"AMX_IMAP_PORT":    "143",
+	"AMX_SMTP_ADDRESS": "mail.novox.be",
+	"AMX_SMTP_PORT":    "587",
+	"AUTOMX_PORT":      "4243",
+}
+
+func getenvOf(m map[string]string) func(string) string {
+	return func(k string) string { return m[k] }
+}
+
+func testServer(t *testing.T) *httptest.Server {
+	t.Helper()
+	cfg, err := configFrom(getenvOf(capturedEnvironment))
+	if err != nil {
+		t.Fatal(err)
+	}
+	s := httptest.NewServer(newHandler(cfg))
+	t.Cleanup(s.Close)
+	return s
+}
+
+const captured = "testdata/captured"
+
+// A captured request: its first line is the method and the URL the client used, then the headers sent, then after
+// a blank line the body sent (CAPTURED, how the files were written).
+type request struct {
+	method, url string
+	header      [][2]string
+	body        string
+}
+
+func readRequest(t *testing.T, stem string) request {
+	t.Helper()
+	raw, err := os.ReadFile(stem + ".request")
+	if err != nil {
+		t.Fatal(err)
+	}
+	head, body, hasBody := strings.Cut(string(raw), "\n\n")
+	if !hasBody {
+		head = strings.TrimSuffix(head, "\n")
+	}
+	lines := strings.Split(head, "\n")
+	method, target, ok := strings.Cut(lines[0], " ")
+	if !ok {
+		t.Fatalf("%s: first line %q is not METHOD URL", stem, lines[0])
+	}
+	r := request{method: method, url: target, body: body}
+	for _, l := range lines[1:] {
+		k, v, ok := strings.Cut(l, ": ")
+		if !ok {
+			t.Fatalf("%s: header line %q", stem, l)
+		}
+		r.header = append(r.header, [2]string{k, v})
+	}
+	return r
+}
+
+func readFile(t *testing.T, name string) string {
+	t.Helper()
+	b, err := os.ReadFile(name)
+	if err != nil {
+		t.Fatal(err)
+	}
+	return string(b)
+}
+
+// A fixture asks for its body to differ only where DIFFERENCES says so: a stem with a .corrected.body is answered
+// with that, and its Content-Length is the corrected body's.
+func expectedBody(t *testing.T, stem string) (body string, corrected bool) {
+	if _, err := os.Stat(stem + ".corrected.body"); err == nil {
+		return readFile(t, stem+".corrected.body"), true
+	}
+	return readFile(t, stem+".body"), false
+}
+
+func TestEveryCapturedRequestIsAnsweredAsAutomxAnswered(t *testing.T) {
+	stems, _ := filepath.Glob(filepath.Join(captured, "*.request"))
+	if len(stems) < 17 {
+		t.Fatalf("%d captured requests found, want the 17 of issue 1630", len(stems))
+	}
+	srv := testServer(t)
+	client := &http.Client{CheckRedirect: func(*http.Request, []*http.Request) error { return http.ErrUseLastResponse }}
+	for _, f := range stems {
+		stem := strings.TrimSuffix(f, ".request")
+		t.Run(filepath.Base(stem), func(t *testing.T) {
+			rq := readRequest(t, stem)
+			u, err := url.Parse(rq.url)
+			if err != nil {
+				t.Fatal(err)
+			}
+			// The mesh's route reaches the program with the client's name and scheme; the program is told them in
+			// the forwarding headers (the Location of fixture 14 holds them).
+			req, err := http.NewRequest(rq.method, srv.URL+u.RequestURI(), strings.NewReader(rq.body))
+			if err != nil {
+				t.Fatal(err)
+			}
+			for _, h := range rq.header {
+				req.Header.Set(h[0], h[1])
+			}
+			req.Host = u.Host
+			req.Header.Set("X-Forwarded-Proto", u.Scheme)
+			resp, err := client.Do(req)
+			if err != nil {
+				t.Fatal(err)
+			}
+			defer resp.Body.Close()
+			got, _ := io.ReadAll(resp.Body)
+
+			if want := strings.TrimRight(readFile(t, stem+".status"), "\n"); resp.Status != want {
+				t.Errorf("status %q, captured %q", resp.Status, want)
+			}
+			wantBody, corrected := expectedBody(t, stem)
+			if !bytes.Equal(got, []byte(wantBody)) {
+				t.Errorf("body\n%q\nwant\n%q", got, wantBody)
+			}
+			want := map[string]string{}
+			for _, l := range strings.Split(strings.TrimRight(readFile(t, stem+".headers"), "\n"), "\n") {
+				if k, v, ok := strings.Cut(l, ": "); ok {
+					want[k] = v
+				}
+			}
+			if corrected {
+				want["Content-Length"] = strconv.Itoa(len(wantBody))
+			}
+			// Server names the Python program that answered (DIFFERENCES); Date changes on every request.
+			delete(want, "Server")
+			var extra []string
+			for k := range resp.Header {
+				if k == "Date" || k == "Server" {
+					continue
+				}
+				if _, ok := want[k]; !ok {
+					extra = append(extra, k)
+				}
+			}
+			sort.Strings(extra)
+			if len(extra) > 0 {
+				t.Errorf("headers the capture does not have: %v", extra)
+			}
+			for k, v := range want {
+				if g := resp.Header.Get(k); g != v {
+					t.Errorf("header %s: %q, captured %q", k, g, v)
+				}
+			}
+		})
+	}
+}
+
+// DIFFERENCES: the one change clause 9 of ADR 0480 allows to an answer is the IMAP server's name, written from
+// AMX_IMAP_ADDRESS where automx wrote an empty one.
+func TestTheOnlyCorrectedAnswerIsTheImapServersName(t *testing.T) {
+	corrected, _ := filepath.Glob(filepath.Join(captured, "*.corrected.body"))
+	if len(corrected) != 3 {
+		t.Fatalf("%d corrected answers, want the three Thunderbird answers (01, 02, 03): %v", len(corrected), corrected)
+	}
+	for _, c := range corrected {
+		orig := readFile(t, strings.TrimSuffix(c, ".corrected.body")+".body")
+		want := strings.Replace(orig, "<hostname />", "<hostname>mail.novox.be</hostname>", 1)
+		if strings.Contains(want, "<hostname />") || want == orig {
+			t.Fatalf("%s: the capture has no single empty hostname to correct", c)
+		}
+		if got := readFile(t, c); got != want {
+			t.Errorf("%s differs from the capture by more than the IMAP server's name", c)
+		}
+	}
+}
+
+func TestTheImapServerIsNamedFromTheImapAddress(t *testing.T) {
+	env := map[string]string{}
+	for k, v := range capturedEnvironment {
+		env[k] = v
+	}
+	env["AMX_IMAP_ADDRESS"] = "imap.example.test"
+	env["AMX_IMAP_PORT"] = "993"
+	cfg, err := configFrom(getenvOf(env))
+	if err != nil {
+		t.Fatal(err)
+	}
+	rec := httptest.NewRecorder()
+	newHandler(cfg).ServeHTTP(rec, httptest.NewRequest("GET", "/mail/config-v1.1.xml?emailaddress=a@novox.be", nil))
+	body := rec.Body.String()
+	if !strings.Contains(body, `<incomingServer type="imap"><hostname>imap.example.test</hostname><port>993</port>`) {
+		t.Errorf("incoming server not named from AMX_IMAP_ADDRESS and AMX_IMAP_PORT: %s", body)
+	}
+	if !strings.Contains(body, `<outgoingServer type="smtp"><hostname>mail.novox.be</hostname><port>587</port>`) {
+		t.Errorf("outgoing server changed: %s", body)
+	}
+}
+
+func TestEveryDomainOfTheEnvironmentIsServed(t *testing.T) {
+	env := map[string]string{}
+	for k, v := range capturedEnvironment {
+		env[k] = v
+	}
+	env["AMX_MAIL_DOMAINS"] = "novox.be, example.test"
+	cfg, err := configFrom(getenvOf(env))
+	if err != nil {
+		t.Fatal(err)
+	}
+	h := newHandler(cfg)
+	for _, d := range []string{"novox.be", "example.test"} {
+		rec := httptest.NewRecorder()
+		h.ServeHTTP(rec, httptest.NewRequest("GET", "/mail/config-v1.1.xml?emailaddress=a@"+d, nil))
+		if rec.Code != 200 || !strings.Contains(rec.Body.String(), "<domain>"+d+"</domain>") {
+			t.Errorf("%s: %d %s", d, rec.Code, rec.Body.String())
+		}
+	}
+}
+
+// Failure is loud (issue 1631 AC2): a missing variable stops the program and its name is in the message.
+func TestAMissingVariableStopsTheProgramNamingIt(t *testing.T) {
+	for name := range capturedEnvironment {
+		t.Run(name, func(t *testing.T) {
+			env := map[string]string{}
+			for k, v := range capturedEnvironment {
+				env[k] = v
+			}
+			delete(env, name)
+			if _, err := configFrom(getenvOf(env)); err == nil || !strings.Contains(err.Error(), name) {
+				t.Fatalf("configFrom without %s: %v", name, err)
+			}
+			var out bytes.Buffer
+			if code := run(getenvOf(env), &out, func(*http.Server) error { t.Fatal("served without its configuration"); return nil }); code == 0 || !strings.Contains(out.String(), name) {
+				t.Errorf("run without %s: exit %d, said %q", name, code, out.String())
+			}
+		})
+	}
+}
+
+func TestAPortThatIsNotANumberIsRefusedNamingIt(t *testing.T) {
+	env := map[string]string{}
+	for k, v := range capturedEnvironment {
+		env[k] = v
+	}
+	env["AMX_SMTP_PORT"] = "submission"
+	if _, err := configFrom(getenvOf(env)); err == nil || !strings.Contains(err.Error(), "AMX_SMTP_PORT") {
+		t.Fatalf("got %v", err)
+	}
+}

modules/mailu/cmd/automx/main.go

@@ -0,0 +1,290 @@
+// automx answers mail clients' autoconfiguration requests for the domains mailu serves: Thunderbird's
+// /mail/config-v1.1.xml, Outlook's /autodiscover/autodiscover.xml and Apple's /mobileconfig. It replaces the
+// Python automx2 image (novox/hq ADR 0480 clauses 1, 9, 10): standard library only, no database, every answer
+// made from mailu's environment at the start, so a change of the domains, servers or ports reaches clients when
+// the program is started again.
+//
+// The answers are those automx2 2021.6 gave, captured in testdata/captured (CAPTURED, issue 1630), byte for byte,
+// but for the one thing testdata/captured/DIFFERENCES lists: the IMAP server is named, from AMX_IMAP_ADDRESS.
+package main
+
+import (
+	"encoding/xml"
+	"errors"
+	"fmt"
+	"html"
+	"io"
+	"net/http"
+	"os"
+	"strconv"
+	"strings"
+	"time"
+)
+
+// The environment, all required: a program that cannot say which servers clients use must not run (failure is
+// loud). The names are those of mailu's files/mailu.env.
+const (
+	envDomains  = "AMX_MAIL_DOMAINS"
+	envImapHost = "AMX_IMAP_ADDRESS"
+	envImapPort = "AMX_IMAP_PORT"
+	envSmtpHost = "AMX_SMTP_ADDRESS"
+	envSmtpPort = "AMX_SMTP_PORT"
+	envListen   = "AUTOMX_PORT"
+)
+
+type config struct {
+	domains            []string
+	imapHost, smtpHost string
+	imapPort, smtpPort int
+	listen             int
+}
+
+// configFrom reads the environment; it names every variable that is missing or wrong.
+func configFrom(getenv func(string) string) (config, error) {
+	var c config
+	var problems []string
+	text := func(name string) string {
+		v := strings.TrimSpace(getenv(name))
+		if v == "" {
+			problems = append(problems, name+" is not set")
+		}
+		return v
+	}
+	port := func(name string) int {
+		v := text(name)
+		if v == "" {
+			return 0
+		}
+		n, err := strconv.Atoi(v)
+		if err != nil || n < 1 || n > 65535 {
+			problems = append(problems, fmt.Sprintf("%s is %q, not a port number", name, v))
+			return 0
+		}
+		return n
+	}
+	// automx2's add-domains split the list at commas and spaces.
+	for _, d := range strings.FieldsFunc(text(envDomains), func(r rune) bool { return r == ',' || r == ' ' }) {
+		c.domains = append(c.domains, strings.ToLower(d))
+	}
+	c.imapHost, c.imapPort = text(envImapHost), port(envImapPort)
+	c.smtpHost, c.smtpPort = text(envSmtpHost), port(envSmtpPort)
+	c.listen = port(envListen)
+	if len(problems) > 0 {
+		return config{}, errors.New(strings.Join(problems, "; "))
+	}
+	return c, nil
+}
+
+// What automx2 sent (Werkzeug), copied from the capture.
+const (
+	htmlType = "text/html; charset=utf-8"
+	xmlType  = "application/xml"
+
+	notFound = `<!doctype html>
+<html lang=en>
+<title>404 Not Found</title>
+<h1>Not Found</h1>
+<p>The requested URL was not found on the server. If you entered the URL manually please check your spelling and try again.</p>
+`
+	notAllowed = `<!doctype html>
+<html lang=en>
+<title>405 Method Not Allowed</title>
+<h1>Method Not Allowed</h1>
+<p>The method is not allowed for the requested URL.</p>
+`
+	internalError = `<!doctype html>
+<html lang=en>
+<title>500 Internal Server Error</title>
+<h1>Internal Server Error</h1>
+<p>The server encountered an internal error and was unable to complete your request. Either the server is overloaded or there is an error in the application.</p>
+`
+	badRequest = `<!doctype html>
+<html lang=en>
+<title>400 Bad Request</title>
+<h1>Bad Request</h1>
+<p>The browser (or proxy) sent a request that this server could not understand.</p>
+`
+	index = `<html><body>Show Thunderbird-style <a href="/mail/config-v1.1.xml?emailaddress=abc@example.com">XML configuration</a> for abc@example.com.</body></html>`
+)
+
+func reply(w http.ResponseWriter, status int, contentType, body string) {
+	w.Header().Set("Content-Type", contentType)
+	if status != http.StatusNoContent {
+		w.Header().Set("Content-Length", strconv.Itoa(len(body)))
+	}
+	w.WriteHeader(status)
+	if status != http.StatusNoContent {
+		io.WriteString(w, body)
+	}
+}
+
+func missing(w http.ResponseWriter, argument string) {
+	reply(w, http.StatusBadRequest, htmlType, fmt.Sprintf("Missing request argument %q", argument))
+}
+
+type handler struct{ config }
+
+func newHandler(c config) http.Handler { return handler{c} }
+
+func (h handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	var allow string
+	switch r.URL.Path {
+	case "/", "/mail/config-v1.1.xml", "/mobileconfig/":
+		allow = "GET, HEAD, OPTIONS"
+	case "/autodiscover/autodiscover.xml":
+		allow = "POST, OPTIONS"
+	case "/mobileconfig":
+		h.redirectToSlash(w, r)
+		return
+	default:
+		reply(w, http.StatusNotFound, htmlType, notFound)
+		return
+	}
+	if r.Method == http.MethodOptions {
+		w.Header().Set("Allow", allow)
+		reply(w, http.StatusOK, htmlType, "")
+		return
+	}
+	if !strings.Contains(", "+allow+",", ", "+r.Method+",") {
+		w.Header().Set("Allow", allow)
+		reply(w, http.StatusMethodNotAllowed, htmlType, notAllowed)
+		return
+	}
+	switch r.URL.Path {
+	case "/":
+		reply(w, http.StatusOK, htmlType, index)
+	case "/mail/config-v1.1.xml":
+		h.byAddress(w, r.URL.Query().Get("emailaddress"), r.URL.Query().Has("emailaddress"), "emailaddress", h.thunderbird)
+	case "/mobileconfig/":
+		h.byAddress(w, r.URL.Query().Get("emailaddress"), r.URL.Query().Has("emailaddress"), "emailaddress", h.apple)
+	case "/autodiscover/autodiscover.xml":
+		h.outlook(w, r)
+	}
+}
+
+// byAddress is the part the three protocols share: the address is required, and a domain that is not served is
+// answered with no content.
+func (h handler) byAddress(w http.ResponseWriter, address string, present bool, argument string, answer func(http.ResponseWriter, int, string)) {
+	if !present {
+		missing(w, argument)
+		return
+	}
+	domain := strings.ToLower(address[strings.LastIndex(address, "@")+1:])
+	for i, d := range h.domains {
+		if strings.Contains(address, "@") && d == domain {
+			answer(w, i, d)
+			return
+		}
+	}
+	reply(w, http.StatusNoContent, htmlType, "")
+}
+
+// thunderbird is Mozilla's autoconfiguration, config-v1.1. The provider id is automx2's: the provider rows were
+// numbered 1, 11, 21 ... by add-domains.
+func (h handler) thunderbird(w http.ResponseWriter, i int, domain string) {
+	d := html.EscapeString(domain)
+	server := func(kind, host string, port int) string {
+		tag := map[string]string{"imap": "incomingServer", "smtp": "outgoingServer"}[kind]
+		return fmt.Sprintf(`<%s type="%s"><hostname>%s</hostname><port>%d</port><socketType>STARTTLS</socketType>`+
+			`<username>%%EMAILADDRESS%%</username><authentication>password-cleartext</authentication></%s>`,
+			tag, kind, html.EscapeString(host), port, tag)
+	}
+	body := fmt.Sprintf(`<clientConfig version="1.1"><emailProvider id="automx2-%d"><identity /><domain>%s</domain>`+
+		`<displayName>%s</displayName><displayShortName>%s</displayShortName>%s%s</emailProvider></clientConfig>`,
+		1+10*i, d, d, d, server("imap", h.imapHost, h.imapPort), server("smtp", h.smtpHost, h.smtpPort))
+	reply(w, http.StatusOK, xmlType, body)
+}
+
+// apple and outlook answer a served domain as automx2 did: with an error (DIFFERENCES, issue 1691). They are
+// kept as captured here, so the move to a Go program changes the answer only where clause 9 says.
+func (h handler) apple(w http.ResponseWriter, _ int, _ string) {
+	reply(w, http.StatusBadRequest, htmlType, badRequest)
+}
+
+// redirectToSlash is Werkzeug's strict-slash redirect, to the name the client used.
+func (h handler) redirectToSlash(w http.ResponseWriter, r *http.Request) {
+	scheme := "http"
+	if p := strings.TrimSpace(strings.Split(r.Header.Get("X-Forwarded-Proto"), ",")[0]); p != "" {
+		scheme = p
+	}
+	host := r.Host
+	if f := strings.TrimSpace(strings.Split(r.Header.Get("X-Forwarded-Host"), ",")[0]); f != "" {
+		host = f
+	}
+	target := scheme + "://" + host + "/mobileconfig/"
+	if r.URL.RawQuery != "" {
+		target += "?" + r.URL.RawQuery
+	}
+	w.Header().Set("Location", target)
+	e := html.EscapeString(target)
+	reply(w, http.StatusPermanentRedirect, htmlType, fmt.Sprintf(`<!doctype html>
+<html lang=en>
+<title>Redirecting...</title>
+<h1>Redirecting...</h1>
+<p>You should be redirected automatically to the target URL: <a href="%s">%s</a>. If not, click the link.
+`, e, e))
+}
+
+// outlook reads the request's EMailAddress anywhere in the document, whatever the namespace. A body that is not
+// one XML document is automx2's 500.
+func (h handler) outlook(w http.ResponseWriter, r *http.Request) {
+	dec := xml.NewDecoder(io.LimitReader(r.Body, 1<<20))
+	var address string
+	var found, elements, inAddress = false, 0, false
+	for {
+		tok, err := dec.Token()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			reply(w, http.StatusInternalServerError, htmlType, internalError)
+			return
+		}
+		switch t := tok.(type) {
+		case xml.StartElement:
+			elements++
+			if t.Name.Local == "EMailAddress" && !found {
+				inAddress = true
+			}
+		case xml.CharData:
+			if inAddress {
+				address += string(t)
+			}
+		case xml.EndElement:
+			if inAddress && t.Name.Local == "EMailAddress" {
+				inAddress, found = false, true
+			}
+		}
+	}
+	if elements == 0 {
+		reply(w, http.StatusInternalServerError, htmlType, internalError)
+		return
+	}
+	h.byAddress(w, strings.TrimSpace(address), found, "EMailAddress", func(w http.ResponseWriter, _ int, _ string) {
+		reply(w, http.StatusInternalServerError, htmlType, internalError)
+	})
+}
+
+// run is the program: configuration from the environment, then serving. A configuration that cannot be read is
+// said, with the variables' names, and the exit code is not zero.
+func run(getenv func(string) string, out io.Writer, serve func(*http.Server) error) int {
+	c, err := configFrom(getenv)
+	if err != nil {
+		fmt.Fprintf(out, "automx: %v\n", err)
+		return 1
+	}
+	srv := &http.Server{
+		Addr:              ":" + strconv.Itoa(c.listen),
+		Handler:           newHandler(c),
+		ReadHeaderTimeout: 10 * time.Second,
+	}
+	if err := serve(srv); err != nil {
+		fmt.Fprintf(out, "automx: %v\n", err)
+		return 1
+	}
+	return 0
+}
+
+func main() {
+	os.Exit(run(os.Getenv, os.Stderr, func(s *http.Server) error { return s.ListenAndServe() }))
+}

modules/mailu/cmd/automx/manifest_test.go

@@ -0,0 +1,203 @@
+package main
+
+import (
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+// The digest route-proxy's `trust` artifact runs: one alpine image is held for both (ADR 0480 clause 3). It was
+// read from mesh-controller's modules/route-proxy/module.json and is the one hello-web runs.
+const alpineDigest = "alpine@sha256:28bd5fe8b56d1bd048e5babf5b10710ebe0bae67db86916198a6eec434943f8b"
+
+type manifest struct {
+	Tools     []string         `json:"tools"`
+	Resources []map[string]any `json:"resources"`
+	Listens   []struct {
+		Name string `json:"name"`
+		Port int    `json:"port"`
+	} `json:"listens"`
+	Data struct {
+		Own []struct {
+			ID   string `json:"id"`
+			Path string `json:"path"`
+		} `json:"own"`
+	} `json:"data"`
+	Build map[string]any `json:"build"`
+}
+
+func readManifest(t *testing.T) manifest {
+	t.Helper()
+	var m manifest
+	if err := json.Unmarshal([]byte(readFile(t, "../../module.json")), &m); err != nil {
+		t.Fatal(err)
+	}
+	return m
+}
+
+func (m manifest) resource(id string) map[string]any {
+	for _, r := range m.Resources {
+		if r["id"] == id {
+			return r
+		}
+	}
+	return nil
+}
+
+func (m manifest) artifact(name string) map[string]any {
+	arts, _ := m.Build["artifacts"].([]any)
+	for _, a := range arts {
+		if a, _ := a.(map[string]any); a["name"] == name {
+			return a
+		}
+	}
+	return nil
+}
+
+func strs(v any) []string {
+	var out []string
+	l, _ := v.([]any)
+	for _, e := range l {
+		out = append(out, e.(string))
+	}
+	return out
+}
+
+// Clause 2: a Go bundle from a package of the module's own go.mod, stamped for alpine; an archive resource unpacks
+// it; the container mounts that read-only at /opt/mesh, calls the program there and names the archive in restart-on.
+func TestAutomxIsAGoBundleForAlpineMountedAtOptMeshAndRestartedWithIt(t *testing.T) {
+	m := readManifest(t)
+	b := m.artifact("automx")
+	if b == nil || b["kind"] != "bundle" || b["language"] != "go" || b["system"] != "alpine" || b["from"] != "cmd/automx" || b["binary"] != "automx" {
+		t.Fatalf("artifact automx is %v, want a Go bundle, system alpine, from cmd/automx, binary automx", b)
+	}
+	if _, loads := b["loads"]; loads {
+		t.Errorf("a program run in a container is not loaded by the tool runner: %v", b["loads"])
+	}
+	goMod := readFile(t, "../../go.mod")
+	if !strings.HasPrefix(goMod, "module mailu\n") {
+		t.Errorf("the module's go.mod is %q; the bundle is a package of it", goMod)
+	}
+	if _, err := os.Stat(filepath.Join("..", "..", filepath.FromSlash(b["from"].(string)), "main.go")); err != nil {
+		t.Errorf("the bundle's package is not in the module's directory: %v", err)
+	}
+
+	unpack := m.resource("program-automx")
+	if unpack == nil || unpack["type"] != "archive" || unpack["artifact"] != "automx" || unpack["unknown"] != "program" {
+		t.Fatalf("resource program-automx is %v, want an archive of the bundle", unpack)
+	}
+	where, _ := unpack["path"].(string)
+	c := m.resource("automx")
+	if c == nil || c["type"] != "container" {
+		t.Fatalf("no container automx: %v", c)
+	}
+	if got := strs(c["volumes"]); len(got) != 1 || got[0] != where+":/opt/mesh:ro" {
+		t.Errorf("volumes %v, want the archive's place %q mounted read-only at /opt/mesh", got, where)
+	}
+	if got := strs(c["args"]); len(got) != 1 || got[0] != "/opt/mesh/automx" {
+		t.Errorf("args %v, want the program at /opt/mesh/automx", got)
+	}
+	if !contains(strs(c["restart-on"]), "program-automx") {
+		t.Errorf("restart-on %v does not name the archive: a new program would leave the old one running", c["restart-on"])
+	}
+	if !contains(strs(c["restart-on"]), "config-env") {
+		t.Errorf("restart-on %v does not name the environment file the program reads at its start", c["restart-on"])
+	}
+}
+
+// Clause 3: an upstream artifact pinned by digest, the one route-proxy's trust artifact runs. automx's own design
+// builds no image from a Dockerfile and has no Dockerfile or base to build one on; the catalogue as such does not
+// refuse the image kind (novox/hq ADR 0487 clause 13).
+func TestAutomxRunsTheMirroredAlpineImageAndBuildsNoImage(t *testing.T) {
+	m := readManifest(t)
+	c := m.resource("automx")
+	base := m.artifact(c["artifact"].(string))
+	if base == nil || base["kind"] != "upstream" || base["from"] != alpineDigest {
+		t.Errorf("the container runs artifact %v, want an upstream artifact %s", base, alpineDigest)
+	}
+	if _, has := c["image"]; has {
+		t.Errorf("the container names an image %v, fetched from a registry on the machine", c["image"])
+	}
+	for _, a := range m.Build["artifacts"].([]any) {
+		if a.(map[string]any)["kind"] == "image" {
+			t.Errorf("artifact %v is an image built from a Dockerfile, which automx's design (ADR 0480) does not use", a)
+		}
+	}
+	if _, has := m.Build["on"]; has {
+		t.Errorf("build.on %v: nothing is built on a base image any more", m.Build["on"])
+	}
+	for _, gone := range []string{"../../automx/Dockerfile", "../../automx"} {
+		if _, err := os.Stat(gone); err == nil {
+			t.Errorf("%s is still there", gone)
+		}
+	}
+}
+
+// Clause 1: the container stays as it was for what watches it.
+func TestAutomxKeepsItsContainerNameNetworkPortAndEnvironment(t *testing.T) {
+	m := readManifest(t)
+	c := m.resource("automx")
+	if c["name"] != "mailu-automx" || c["network"] != "mailu" {
+		t.Errorf("container %v on network %v, want mailu-automx on mailu", c["name"], c["network"])
+	}
+	if got := strs(c["ports"]); len(got) != 1 || got[0] != "4243" {
+		t.Errorf("ports %v, want 4243", got)
+	}
+	if got := strs(c["env-file"]); len(got) != 1 || got[0] != "${dir:state}/mailu.env" {
+		t.Errorf("env-file %v, want mailu's environment only", got)
+	}
+	if !strings.Contains("\n"+readFile(t, "../../files/mailu.env"), "\nAUTOMX_PORT=4243\n") {
+		t.Errorf("mailu.env does not say AUTOMX_PORT=4243")
+	}
+	for _, l := range m.Listens {
+		if l.Name == "autoconfig" && l.Port == 4243 {
+			return
+		}
+	}
+	t.Errorf("the autoconfig endpoint is not on 4243: %v", m.Listens)
+}
+
+// Clause 10: a database nobody reads is gone from the declaration (the file stays on disk), and the container says
+// whether it answers with one captured request and its captured answer.
+func TestAutomxKeepsNoDatabaseAndSaysWhetherItAnswers(t *testing.T) {
+	m := readManifest(t)
+	if m.resource("data-automx") != nil {
+		t.Errorf("the data-automx directory is still declared")
+	}
+	for _, it := range m.Data.Own {
+		if strings.Contains(it.ID, "automx") || strings.Contains(it.Path, "data-automx") {
+			t.Errorf("data item %v is still declared", it)
+		}
+	}
+	for _, tool := range m.Tools {
+		if tool == "automx_rows" {
+			t.Errorf("the tool automx_rows reads a database that no longer exists (issue 1700)")
+		}
+	}
+	h, _ := m.resource("automx")["health"].(map[string]any)
+	if h["kind"] != "http" || h["endpoint"] != "autoconfig" {
+		t.Fatalf("health %v, want an http check of the autoconfig endpoint", h)
+	}
+	// The request is captured fixture 06 and the answer its status and body.
+	rq := readRequest(t, filepath.Join(captured, "06-autoconfig-root"))
+	if u := strings.SplitN(rq.url, "/", 4); "/"+u[len(u)-1] != h["path"] || rq.method != "GET" {
+		t.Errorf("health path %v is not captured request %s %s", h["path"], rq.method, rq.url)
+	}
+	if st := readFile(t, filepath.Join(captured, "06-autoconfig-root.status")); !strings.HasPrefix(st, "200 ") || h["status"] != float64(200) {
+		t.Errorf("health status %v, captured %q", h["status"], st)
+	}
+	if body, _ := h["body"].(string); body == "" || !strings.Contains(readFile(t, filepath.Join(captured, "06-autoconfig-root.body")), body) {
+		t.Errorf("health body %q is not in the captured answer", h["body"])
+	}
+}
+
+func contains(l []string, s string) bool {
+	for _, e := range l {
+		if e == s {
+			return true
+		}
+	}
+	return false
+}

modules/mailu/cmd/automx/testdata/captured/01-thunderbird-autoconfig-ok.corrected.body

@@ -0,0 +1 @@
+<clientConfig version="1.1"><emailProvider id="automx2-1"><identity /><domain>novox.be</domain><displayName>novox.be</displayName><displayShortName>novox.be</displayShortName><incomingServer type="imap"><hostname>mail.novox.be</hostname><port>143</port><socketType>STARTTLS</socketType><username>%EMAILADDRESS%</username><authentication>password-cleartext</authentication></incomingServer><outgoingServer type="smtp"><hostname>mail.novox.be</hostname><port>587</port><socketType>STARTTLS</socketType><username>%EMAILADDRESS%</username><authentication>password-cleartext</authentication></outgoingServer></emailProvider></clientConfig>

modules/mailu/cmd/automx/testdata/captured/02-thunderbird-on-automx-name.corrected.body

@@ -0,0 +1 @@
+<clientConfig version="1.1"><emailProvider id="automx2-1"><identity /><domain>novox.be</domain><displayName>novox.be</displayName><displayShortName>novox.be</displayShortName><incomingServer type="imap"><hostname>mail.novox.be</hostname><port>143</port><socketType>STARTTLS</socketType><username>%EMAILADDRESS%</username><authentication>password-cleartext</authentication></incomingServer><outgoingServer type="smtp"><hostname>mail.novox.be</hostname><port>587</port><socketType>STARTTLS</socketType><username>%EMAILADDRESS%</username><authentication>password-cleartext</authentication></outgoingServer></emailProvider></clientConfig>

modules/mailu/cmd/automx/testdata/captured/03-thunderbird-on-autodiscover-name.corrected.body

@@ -0,0 +1 @@
+<clientConfig version="1.1"><emailProvider id="automx2-1"><identity /><domain>novox.be</domain><displayName>novox.be</displayName><displayShortName>novox.be</displayShortName><incomingServer type="imap"><hostname>mail.novox.be</hostname><port>143</port><socketType>STARTTLS</socketType><username>%EMAILADDRESS%</username><authentication>password-cleartext</authentication></incomingServer><outgoingServer type="smtp"><hostname>mail.novox.be</hostname><port>587</port><socketType>STARTTLS</socketType><username>%EMAILADDRESS%</username><authentication>password-cleartext</authentication></outgoingServer></emailProvider></clientConfig>

modules/mailu/cmd/automx/testdata/captured/CAPTURED

@@ -14,6 +14,13 @@ Each capture is four files with the same stem:
 The files were written from the tool's answers by a script (not by retyping each by hand); the tool returns JSON, so
 a later capture that wants exact bytes needs a tool that writes the answer to a file.
 
+A fixture is not the bytes on the wire in four ways (issue 1701):
+  - Date is left out of .headers (it changes on every request).
+  - .headers are sorted by name.
+  - .status holds the tool's status line without the protocol (the tool reported "HTTP/1.1" apart).
+  - Header names are as the tool's Go HTTP client gives them (canonical case, after the mesh's route), not as
+    automx wrote them.
+
 What the answers show (read, not guessed):
   - GET /mail/config-v1.1.xml?emailaddress=... answers 200 application/xml on all three names; same body on each.
   - The incoming (IMAP) server has an EMPTY hostname (<hostname />), port 143, STARTTLS. The outgoing server is
@@ -27,4 +34,8 @@ What the answers show (read, not guessed):
   - GET /mobileconfig?emailaddress=... redirects (308) to /mobileconfig/?emailaddress=...; for the served domain that
     answers 400 with no profile; unknown domain 204; no emailaddress 400.
   - GET / on autoconfig answers 200 with a small HTML page linking to an example address.
-  - Not captured: the database rows (no mesh tool reads /data/db.sqlite; issue 1630 AC4).
+  - The database rows behind the answers were read once with the tool automx_rows (mailu, issue 1630 AC4), which
+    ran sqlite3 read-only inside mailu-automx. The tool is retired with the database (ADR 0480 clause 10, issue
+    1700), so nothing reads the rows any more; the answers above are what they gave.
+  - The Go program that replaced automx2 answers these requests as they are captured here, but for what
+    DIFFERENCES lists.

modules/mailu/cmd/automx/testdata/captured/DIFFERENCES

@@ -0,0 +1,25 @@
+How the Go program (modules/mailu/cmd/automx) answers differently from the automx2 2021.6 answers captured here
+(issue 1631, ADR 0480 clause 9). automx_test.go answers every .request and compares with the capture; this is the
+whole list of where the two differ.
+
+1. The IMAP server's name (the one correction clause 9 allows). automx2 answered <hostname /> for the incoming
+   server because its setup script read AMX_IMAP_SERVER, which mailu's environment does not set (it sets
+   AMX_IMAP_ADDRESS). The program names it from AMX_IMAP_ADDRESS (and the port from AMX_IMAP_PORT).
+   Fixtures 01, 02 and 03 each have a <stem>.corrected.body: the capture with <hostname /> replaced by
+   <hostname>mail.novox.be</hostname> and nothing else (a test checks that). Their Content-Length is that file's
+   size, 634, not the captured 612.
+
+2. The Server header. The capture has "Server: Werkzeug/3.1.9 Python/3.9.5". The program sends no Server header, and
+   Date, which the captured .headers leave out, is sent as net/http sends it.
+
+Not changed, though issue 1691 calls them faults; they are kept as captured because clause 9 allows only the first
+correction, and their cause is not known from the capture:
+  - Outlook's POST for a served domain (fixture 08) answers 500.
+  - Apple's /mobileconfig/ for a served domain (fixture 15) answers 400 with no profile.
+  Whether automx2 failed there because of the empty IMAP name is a guess; it can be tested only against the
+  running program after the delivery. Issue 1691 stays open for them.
+
+Assumptions the fixtures do not settle (answers to requests nobody captured): a domain is compared in lower case;
+an address without "@" is an unknown domain (204); HEAD is answered as GET and OPTIONS with the Allow header and
+no body; the redirect of /mobileconfig takes its scheme and host from X-Forwarded-Proto and X-Forwarded-Host when
+present (the route sends the client's, as fixture 14's Location shows) and from the request otherwise.

modules/mailu/go.mod

@@ -0,0 +1,3 @@
+module mailu
+
+go 1.22

modules/mailu/module.json

@@ -71,8 +71,7 @@
     "mailu_list_domains",
     "mailu_read_mail",
     "mailu_search_mail",
-    "mailu_health",
+    "mailu_health"
-    "automx_rows"
   ],
   "emits": [
     "user.created",
@@ -216,12 +215,6 @@
         "class": "rebuildable",
         "why": "certificates, issued again"
       },
-      {
-        "id": "automx",
-        "path": "${dir:data-automx}",
-        "class": "rebuildable",
-        "why": "client autoconfiguration, written again"
-      },
       {
         "id": "fetchmail",
         "path": "${dir:data-fetchmail}",
@@ -308,12 +301,6 @@
       "mode": "0700",
       "unknown": "program"
     },
-    {
-      "id": "data-automx",
-      "type": "directory",
-      "mode": "0700",
-      "unknown": "program"
-    },
     {
       "id": "config-env",
       "type": "file",
@@ -681,11 +668,25 @@
       "takes-config": ["domain", "proxy-address", "sitename", "website", "url", "container"],
       "merge": "json"
     },
+    {
+      "id": "program-automx",
+      "type": "archive",
+      "path": "${dir:state}/automx",
+      "artifact": "automx",
+      "unknown": "program"
+    },
     {
       "id": "automx",
       "type": "container",
       "name": "mailu-automx",
-      "artifact": "automx",
+      "artifact": "alpine",
+      "health": {
+        "kind": "http",
+        "endpoint": "autoconfig",
+        "path": "/",
+        "status": 200,
+        "body": "Show Thunderbird-style"
+      },
       "network": "mailu",
       "env-file": [
         "${dir:state}/mailu.env"
@@ -694,17 +695,18 @@
         "4243"
       ],
       "volumes": [
-        "${dir:data-automx}:/data"
+        "${dir:state}/automx:/opt/mesh:ro"
+      ],
+      "args": [
+        "/opt/mesh/automx"
+      ],
+      "restart-on": [
+        "program-automx",
+        "config-env"
       ]
     }
   ],
   "build": {
-    "on": [
-      {
-        "arg": "PYTHON_BASE",
-        "image": "python@sha256:25f3cfeaceca14921366af4d1240b56457ef46273bdb508c7b0e8f469f6fd228"
-      }
-    ],
     "artifacts": [
       {
         "name": "code",
@@ -731,8 +733,16 @@
       },
       {
         "name": "automx",
-        "kind": "image",
+        "kind": "bundle",
-        "from": "automx/Dockerfile"
+        "language": "go",
+        "system": "alpine",
+        "from": "cmd/automx",
+        "binary": "automx"
+      },
+      {
+        "name": "alpine",
+        "kind": "upstream",
+        "from": "alpine@sha256:28bd5fe8b56d1bd048e5babf5b10710ebe0bae67db86916198a6eec434943f8b"
       },
       {
         "name": "files",

modules/mailu/test/automx-rows.test.ts

@@ -1,103 +0,0 @@
-// What automx_rows reads (novox/hq issue 1630): the rows of automx2's database as stored, through a read-only
-// sqlite3 inside its container. The database here is a real SQLite file made by the test with the tables
-// automx/files/setup-db creates and the rows add-domains writes — with the IMAP server's name empty, the case
-// the live instance is in. The fake container runs each command's statement against that database and prints
-// it the way the image's sqlite3 does in list mode (one line per row, cells apart by "|", nothing for no rows); that sqlite3
-// refuses `-json` ("sqlite3: Error: unknown option: -json", captured from novox/mailu.automx_rows, issue 1630). Run against the compiled module.
-
-import { test } from "node:test";
-import assert from "node:assert/strict";
-import { DatabaseSync } from "node:sqlite";
-
-import { readAutomx, readCommand, selectOf, parseRows, AUTOMX_DATABASE } from "../dist/automx.js";
-
-function database(imapName: string): DatabaseSync {
-  const db = new DatabaseSync(":memory:");
-  db.exec(`
-    CREATE TABLE provider(id INT PRIMARY KEY NOT NULL, name TEXT NOT NULL, short_name TEXT NOT NULL);
-    CREATE TABLE server(id INT PRIMARY KEY NOT NULL, prio INT NOT NULL DEFAULT 10, name TEXT NOT NULL, port INT NOT NULL,
-      type TEXT NOT NULL, socket_type TEXT NOT NULL, user_name TEXT NOT NULL, authentication TEXT NOT NULL);
-    CREATE TABLE domain(id INT PRIMARY KEY NOT NULL, name TEXT NOT NULL, provider_id INT NOT NULL, ldapserver_id INT NULL);
-    CREATE TABLE server_domain(server_id INT NOT NULL, domain_id INT NOT NULL);
-    INSERT INTO provider VALUES (1, 'example.org', 'example.org');
-    INSERT INTO server(id, port, type, name, socket_type, user_name, authentication)
-      VALUES (2, 143, 'imap', '${imapName}', 'STARTTLS', '%EMAILADDRESS%', 'password-cleartext');
-    INSERT INTO server(id, port, type, name, socket_type, user_name, authentication)
-      VALUES (3, 587, 'smtp', 'mail.example.org', 'STARTTLS', '%EMAILADDRESS%', 'password-cleartext');
-    INSERT INTO domain VALUES (5, 'example.org', 1, NULL);
-    INSERT INTO server_domain VALUES (2, 5), (3, 5);
-  `);
-  return db;
-}
-
-function container(db: DatabaseSync, asked: string[][] = []) {
-  return async (_name: string, command: string[]) => {
-    asked.push(command);
-    if (command.includes("-json")) throw Object.assign(new Error("Command failed: docker exec"), { stderr: "sqlite3: Error: unknown option: -json\n" });
-    const rows = db.prepare(command[command.length - 1]).all() as unknown as Record<string, string>[];
-    return rows.length === 0 ? "" : rows.map((r) => Object.values(r).join("|")).join("\n") + "\n";
-  };
-}
-
-test("the rows come back as stored, and an empty server name is said", async () => {
-  const answer = await readAutomx(container(database("")), "mailu-automx");
-  assert.equal(answer.database, AUTOMX_DATABASE);
-  assert.deepEqual(answer.unreadable, {});
-  assert.deepEqual(answer.tables.provider, [{ id: 1, name: "example.org", short_name: "example.org" }]);
-  assert.deepEqual(answer.tables.domain, [{ id: 5, name: "example.org", provider_id: 1, ldapserver_id: null }]);
-  assert.deepEqual(answer.tables.server_domain, [{ server_id: 2, domain_id: 5 }, { server_id: 3, domain_id: 5 }]);
-  assert.deepEqual(
-    answer.tables.server.map((s) => [s.id, s.type, s.name, s.port]),
-    [[2, "imap", "", 143], [3, "smtp", "mail.example.org", 587]],
-  );
-  assert.deepEqual(answer.empty_names, [{ id: 2, type: "imap" }]);
-});
-
-test("a named IMAP server is not reported empty", async () => {
-  const answer = await readAutomx(container(database("mail.example.org")), "mailu-automx");
-  assert.deepEqual(answer.empty_names, []);
-});
-
-test("every command opens the file read-only and runs one fixed SELECT", async () => {
-  const asked: string[][] = [];
-  await readAutomx(container(database("x"), asked), "mailu-automx");
-  assert.equal(asked.length, 4);
-  for (const c of asked) {
-    assert.deepEqual(c.slice(0, 3), ["sqlite3", "-readonly", AUTOMX_DATABASE]);
-    assert.match(c[3], /^SELECT /);
-    assert.equal(c.length, 4);
-    assert.ok(!c.includes("-json"));
-  }
-  assert.deepEqual(readCommand("provider"), ["sqlite3", "-readonly", AUTOMX_DATABASE, selectOf("provider")]);
-});
-
-test("a table that cannot be read is said and does not hide the others", async () => {
-  const db = database("x");
-  const exec = async (name: string, command: string[]) => {
-    if (command[3].includes("FROM domain ")) throw Object.assign(new Error("Command failed: docker exec"), { stderr: "Error: unable to open database file\nmore" });
-    return container(db)(name, command);
-  };
-  const answer = await readAutomx(exec, "mailu-automx");
-  assert.deepEqual(answer.unreadable, { domain: "Error: unable to open database file" });
-  assert.equal(answer.tables.provider.length, 1);
-  assert.equal(answer.tables.domain, undefined);
-});
-
-test("a NULL, an empty text, a number and a text holding a bar or a newline are read apart", () => {
-  const hex = (t: string) => Buffer.from(t).toString("hex").toUpperCase();
-  const line = [`integer:${hex("5")}`, `text:${hex("a|b\nc")}`, "text:", "null:"].join("|");
-  const rows = parseRows("domain", line + "\n");
-  assert.deepEqual(rows, [{ id: 5, name: "a|b\nc", provider_id: "", ldapserver_id: null }]);
-});
-
-test("output that is not cells is an unreadable table, not a guess", async () => {
-  const exec = async () => "Error: something else\n";
-  const answer = await readAutomx(exec, "mailu-automx");
-  assert.equal(Object.keys(answer.unreadable).length, 4);
-});
-
-test("the image's refusal of -json is said as the table's reason", async () => {
-  const exec = async (_n: string, command: string[]) => container(database("x"))("", ["sqlite3", "-json", ...command.slice(1)]);
-  const answer = await readAutomx(exec, "mailu-automx");
-  assert.deepEqual(answer.unreadable.domain, "sqlite3: Error: unknown option: -json");
-});

modules/mailu/test/mail-flows.test.ts

@@ -135,7 +135,6 @@ test("the health tool is served without the admin API, on the smtp container it
   await import("../dist/tools/index.js");
   const mailu = collectTools({ MESH_MAILU_SMTP_CONTAINER: "mailu-smtp" }).find((m) => m.module === "mailu");
   const names = (mailu?.tools ?? []).map((t) => t.name);
-  assert.deepEqual(names, ["mailu_health", "automx_rows"]);
+  assert.deepEqual(names, ["mailu_health"]);
   assert.match(mailu!.tools[0].description, /inside mailu-smtp/);
-  assert.match(mailu!.tools[1].description, /read-only, inside mailu-automx/);
 });

modules/mailu/tools/index.ts

@@ -4,7 +4,6 @@
 
 import { registerModuleTools, type ToolDefinition } from "@novox/mesh-sdk/tools";
 import { MailuClient } from "../client.js";
-import { readAutomx } from "../automx.js";
 import { dockerExec, mailFlows, DEFERRED_BOUND_SECONDS, PUBLIC_NAME, SPREAD_DOMAINS } from "../health.js";
 
 /**
@@ -27,23 +26,6 @@ export function getHealthTool(env: NodeJS.ProcessEnv): ToolDefinition {
   };
 }
 
-/**
- * What automx holds, as stored (novox/hq issue 1630): the rows behind the answers it gives mail clients. It needs
- * no admin API, only the automx container, so like the health tool it is served without the API.
- */
-export function getAutomxTool(env: NodeJS.ProcessEnv): ToolDefinition {
-  const container = env.MESH_MAILU_AUTOMX_CONTAINER || "mailu-automx";
-  return {
-    name: "automx_rows",
-    description:
-      `Read the autoconfiguration module's database, as stored, read-only, inside ${container}: its provider, ` +
-      "server, domain and server_domain rows, and the servers whose name is empty (a mail client is then told " +
-      "an empty host name). Writes nothing.",
-    input: {},
-    run: async () => readAutomx(dockerExec(), container),
-  };
-}
-
 export function getMailuTools(mailu: MailuClient): ToolDefinition[] {
   return [
     {
@@ -191,5 +173,5 @@ registerModuleTools("mailu", (env) => {
   } catch {
     tools = [];
   }
-  return [...tools, getHealthTool(env), getAutomxTool(env)];
+  return [...tools, getHealthTool(env)];
 });

modules/mailu/tsconfig.json

@@ -8,5 +8,5 @@
     "skipLibCheck": true,
     "noEmit": true
   },
-  "include": ["client.ts", "health.ts", "automx.ts", "index.ts", "tools/index.ts"]
+  "include": ["client.ts", "health.ts", "index.ts", "tools/index.ts"]
 }

modules/mesh-build-go/README.md

@@ -40,6 +40,12 @@ with `GOTOOLCHAIN=local`, `GOFLAGS=-mod=mod` and the module's cache directory. E
 environment built from scratch (`StepRunner`): `PATH`, `HOME` and what the step passes. Workspaces older than a day
 are removed.
 
+A pin on a pull request's head (issue 1148): when `go mod download` fails on a `git.novox.be/novox/*` pseudo-version, the
+fetch looks for that commit among the forge's `refs/pull/*/head`, places the repository at it under the workspace's
+`pinned/beside/` as a plain directory, and hands it to Go (the fetch's commands, and the build with `GOPROXY=off`) through a
+temporary `-modfile` in the workspace's `pins/` that replaces the module by that directory. A pin Go can fetch is left as
+it is, a pin on no ref fails naming the module and the commit, and a directory that vendors is never resolved.
+
 The account's ssh files (`files/forge`, `files/known_hosts`, `files/gitconfig`) are filled on the node by the
 provisioner's client from the module's entry of `forge-account` (the manifest says `moved`, ADR 0466 §4, ADR 0400 §5).
 The forge writes that entry only once the module has run and reported its key (ADR 0400 §2), so until then the client

modules/mesh-build-go/cmd/mesh-build-go/build.go

@@ -172,6 +172,8 @@ func (m *Module) buildEnv(dir string) []string {
 	mod := "-mod=mod"
 	if _, err := os.Stat(filepath.Join(dir, "vendor", "modules.txt")); err == nil {
 		mod = "-mod=vendor"
+	} else if modfile, ok := m.pinModfile(dir); ok {
+		mod += " -modfile=" + modfile // a pin on a pull request's head the fetch placed beside the workspace (pins.go)
 	}
 	return []string{
 		"CGO_ENABLED=0",

modules/mesh-build-go/cmd/mesh-build-go/fetch.go

@@ -17,6 +17,8 @@ import (
 	"git.novox.be/novox/mesh-sdk/go/buildstep"
 )
 
+var commitOK = regexp.MustCompile(`^[0-9a-f]{40}$`)
+
 // ForgeAlias is the ssh name the forge-account provision sets up in the account's ssh files (ADR 0409 §1); the
 // remote of a fetch is ssh://<it>/<owner>/<repository>.git.
 const ForgeAlias = "mesh-forge"
@@ -37,6 +39,18 @@ type FetchResult struct {
 	Workspace string   `json:"workspace"`
 	Commit    string   `json:"commit"`
 	Modules   []string `json:"modules"`
+	// The merge preview (ADR 0484 clause 3), only when the call gave a base: the trunk commit, the merge commit of the
+	// head onto it, the paths the merge changes, and the tree of each module directory (a directory holding a
+	// module.json) in the merge. A head that does not merge cleanly is an answer: Merge is empty, Conflicts names the
+	// files, and the workspace is left at the trunk commit.
+	Base      string                          `json:"base,omitempty"`
+	Merge     string                          `json:"merge,omitempty"`
+	Conflicts []string                        `json:"conflicts,omitempty"`
+	Changed   []string                        `json:"changed,omitempty"`
+	Trees     map[string]buildstep.ModuleTree `json:"trees,omitempty"`
+	// Beside are the sibling repositories placed as plain directories under the workspace's beside directory, which
+	// build_go_test hands to the tests as MESH_CHECK_BESIDE (ADR 0484 clause 4).
+	Beside []Sibling `json:"beside,omitempty"`
 }
 
 // fetchTool is the fetch step tool.
@@ -52,6 +66,12 @@ func (m *Module) fetchTool() StepTool {
 				"repository": map[string]any{"type": "string", "description": "<owner>/<repository> on the forge"},
 				"commit":     map[string]any{"type": "string", "description": "the full commit, 40 hex digits"},
 				"ref":        map[string]any{"type": "string", "description": "refs/pull/<n>/head when only a pull request's head carries the commit"},
+				"base":       map[string]any{"type": "string", "description": "optional trunk commit, 40 hex digits: the head is merged onto it as the forge's merge would, and the answer carries the merge commit, the files in conflict (an answer, the workspace is then left at the trunk commit), the changed paths and the tree of each module directory"},
+				"beside": map[string]any{"type": "array", "description": "optional sibling repositories the tests read, each placed as a plain directory (no symlink) under the workspace's beside/<name>, which build_go_test gives the tests as MESH_CHECK_BESIDE",
+					"items": map[string]any{"type": "object", "properties": map[string]any{
+						"repository": map[string]any{"type": "string", "description": "<owner>/<repository> on the forge"},
+						"commit":     map[string]any{"type": "string", "description": "the full commit, 40 hex digits"},
+					}, "required": []string{"repository", "commit"}}},
 			},
 			"required": []string{"repository", "commit"},
 		},
@@ -64,6 +84,14 @@ func (m *Module) fetch(ctx context.Context, args map[string]any) (any, error) {
 	repository, _ := args["repository"].(string)
 	commit, _ := args["commit"].(string)
 	ref, _ := args["ref"].(string)
+	base, _ := args["base"].(string)
+	if base != "" && !commitOK.MatchString(base) {
+		return nil, fmt.Errorf("%q is not a trunk commit (40 hex digits)", base)
+	}
+	siblings, err := siblingsArg(args["beside"])
+	if err != nil {
+		return nil, err
+	}
 	if !repositoryOK.MatchString(repository) || strings.Contains(repository, "..") {
 		return nil, fmt.Errorf("%q is not a repository, <owner>/<name>", repository)
 	}
@@ -74,26 +102,70 @@ func (m *Module) fetch(ctx context.Context, args map[string]any) (any, error) {
 	if err := os.MkdirAll(tree, 0o700); err != nil {
 		return nil, err
 	}
-	remote := "ssh://" + ForgeAlias + "/" + repository + ".git"
+	remote := m.remote(repository)
-	if err := buildstep.FetchCommit(ctx, m.Run, tree, remote, commit, ref); err != nil {
+	if err := buildstep.FetchCommit(ctx, m.Run, tree, remote, commit, ref, m.FetchOptions...); err != nil {
+		return nil, err
+	}
+	res := FetchResult{Workspace: id, Commit: commit}
+	if base != "" {
+		if err := m.merge(ctx, &res, tree, remote, base, commit); err != nil {
+			return nil, err
+		}
+	}
+	if res.Beside, err = m.placeSiblings(ctx, root, siblings); err != nil {
 		return nil, err
 	}
 	dirs, err := m.goModDirs(ctx, tree)
 	if err != nil {
 		return nil, err
 	}
+	res.Modules = dirs
+	if base != "" && res.Merge == "" {
+		return res, nil // a conflict: the tree is at the trunk, nothing of the head is built or tested
+	}
 	for _, d := range dirs {
 		if _, err := os.Stat(filepath.Join(tree, d, "vendor", "modules.txt")); err == nil {
 			continue // a module that vendors resolves nothing
 		}
-		for _, verb := range []string{"download", "verify"} {
+		if err := m.downloadModules(ctx, root, filepath.Join(tree, d), d); err != nil {
-			r := m.Run(ctx, m.goEnv(), "go", "-C", filepath.Join(tree, d), "mod", verb)
+			return nil, err
-			if r.Status != 0 || r.Err != "" {
-				return nil, fmt.Errorf("go mod %s in %s: %s", verb, d, causeLine(r.Err+"\n"+r.Stdout+"\n"+r.Stderr))
-			}
 		}
 	}
-	return FetchResult{Workspace: id, Commit: commit, Modules: dirs}, nil
+	return res, nil
+}
+
+// downloadModules downloads and verifies the Go modules of the directory dir (d in the tree). A pin of a forge module
+// that Go cannot fetch is looked for among the forge's pull request heads and handed to Go by a modfile (pins.go); a
+// failure that names no such pin is the first failure.
+func (m *Module) downloadModules(ctx context.Context, root, dir, d string) error {
+	for {
+		failure := m.downloadAndVerify(ctx, dir, d)
+		if failure == nil {
+			return nil
+		}
+		progress, err := m.resolvePins(ctx, root, dir, failure.Error())
+		if err != nil {
+			return err
+		}
+		if !progress {
+			return failure
+		}
+	}
+}
+
+func (m *Module) downloadAndVerify(ctx context.Context, dir, d string) error {
+	for _, verb := range []string{"download", "verify"} {
+		cmd, env := []string{"-C", dir, "mod", verb}, m.goEnvFor(dir)
+		if modfile, ok := m.pinModfile(dir); ok && verb == "verify" {
+			// go mod verify takes no -modfile: it is run on the modfile itself, which names the placed repositories.
+			cmd, env = []string{"-C", filepath.Dir(modfile), "mod", verb}, m.goEnv()
+		}
+		r := m.Run(ctx, env, "go", cmd...)
+		if r.Status != 0 || r.Err != "" {
+			return fmt.Errorf("go mod %s in %s: %s", verb, d, causeLine(r.Err+"\n"+r.Stdout+"\n"+r.Stderr))
+		}
+	}
+	return nil
 }
 
 // goModDirs are the directories of the tree that hold a go.mod, relative to it, in order.
@@ -104,7 +176,7 @@ func (m *Module) goModDirs(ctx context.Context, tree string) ([]string, error) {
 	}
 	dirs := []string{}
 	for _, l := range strings.Split(r.Stdout, "\n") {
-		if l = strings.TrimSpace(l); l != "" {
+		if l = strings.TrimSpace(l); l != "" && !inTestdata(l) {
 			dirs = append(dirs, filepath.ToSlash(filepath.Dir(l)))
 		}
 	}
@@ -112,6 +184,17 @@ func (m *Module) goModDirs(ctx context.Context, tree string) ([]string, error) {
 	return dirs, nil
 }
 
+// inTestdata says a path lies under a directory named testdata, whose go.mod files are fixtures Go ignores, not modules
+// of the tree (issue 1810).
+func inTestdata(path string) bool {
+	for _, seg := range strings.Split(filepath.ToSlash(path), "/") {
+		if seg == "testdata" {
+			return true
+		}
+	}
+	return false
+}
+
 // goEnv is what a go command of a step is given beyond the base environment: the installed go alone (GOTOOLCHAIN=local, ADR 0477 §1: no toolchain is ever downloaded),
 // modules resolved by their go.mod and go.sum, the module's own caches, the mesh's own modules fetched directly (by
 // git, through the account's rewrite of the forge's address to ssh), and nothing that asks a question. For a directory
@@ -134,6 +217,8 @@ func (m *Module) goEnvFor(dir string) []string {
 	env := m.goEnv()
 	if _, err := os.Stat(filepath.Join(dir, "vendor", "modules.txt")); err == nil {
 		env = append(env, "GOFLAGS=-mod=vendor") // the last value of a name is the one used
+	} else if modfile, ok := m.pinModfile(dir); ok {
+		env = append(env, "GOFLAGS=-mod=mod -modfile="+modfile) // a pin on a pull request's head (pins.go)
 	}
 	return env
 }

modules/mesh-build-go/cmd/mesh-build-go/fetch_test.go

@@ -30,7 +30,8 @@ type fakeStep struct {
 	gomods  string
 	gate    chan struct{} // when set, the first git command waits for it
 	goRule  func(line string) forgekey.Ran
-	vendors []string // directories (relative to the tree) that get a vendor/modules.txt at checkout
+	vendors []string                               // directories (relative to the tree) that get a vendor/modules.txt at checkout
+	rule    func(line string) (forgekey.Ran, bool) // answers a command before the defaults do
 }
 
 func (f *fakeStep) run(ctx context.Context, env []string, name string, args ...string) forgekey.Ran {
@@ -41,6 +42,11 @@ func (f *fakeStep) run(ctx context.Context, env []string, name string, args ...s
 	if f.gate != nil && strings.Contains(line, " init ") {
 		<-f.gate
 	}
+	if f.rule != nil {
+		if r, ok := f.rule(line); ok {
+			return r
+		}
+	}
 	switch {
 	case name == "git" && strings.Contains(line, " rev-parse HEAD"):
 		return forgekey.Ran{Stdout: commitSHA + "\n"}

modules/mesh-build-go/cmd/mesh-build-go/gomoddirs_test.go

@@ -0,0 +1,27 @@
+package main
+
+import (
+	"context"
+	"reflect"
+	"testing"
+
+	"git.novox.be/novox/mesh-sdk/go/forgekey"
+)
+
+// 1810/AC1: the go.mod files under a testdata directory are fixtures Go itself ignores, not modules of the tree, so
+// the build modules neither test nor digest them (a repository holding this module held one whose test reads
+// MESH_CHECK_BESIDE, which failed every check of it).
+func TestGoModDirsLeaveOutTheFixturesUnderTestdata(t *testing.T) {
+	m := &Module{}
+	m.Run = func(ctx context.Context, env []string, name string, args ...string) forgekey.Ran {
+		return forgekey.Ran{Stdout: "checks/deps/go.mod\ngo.mod\nmodules/x/cmd/x/testdata/repos/beside/go.mod\nmodules/x/go.mod\ntestdata/go.mod\n"}
+	}
+	got, err := m.goModDirs(context.Background(), t.TempDir())
+	if err != nil {
+		t.Fatal(err)
+	}
+	want := []string{".", "checks/deps", "modules/x"}
+	if !reflect.DeepEqual(got, want) {
+		t.Fatalf("go.mod directories = %v, want %v", got, want)
+	}
+}

modules/mesh-build-go/cmd/mesh-build-go/integration.go

@@ -60,7 +60,7 @@ func (m *Module) integration(ctx context.Context, workspace, tree string, packag
 		return nil, fmt.Errorf("the integration level's bus: %w", err)
 	}
 	defer stopBus()
-	env := []string{"MESH_TEST_POSTGRES=" + postgres, "MESH_TEST_NATS=" + nats}
+	env := append([]string{"MESH_TEST_POSTGRES=" + postgres, "MESH_TEST_NATS=" + nats}, m.besideEnv(workspace)...)
 	// Compiling counts as setup: the tests are built once, here, with the addresses a TestMain may read, and the run
 	// below finds them built. Whether they compile is for the run to say; its failure is not read here.
 	for _, d := range dirs {

modules/mesh-build-go/cmd/mesh-build-go/module.go

@@ -37,6 +37,10 @@ type Module struct {
 	// both outside the account's home (ADR 0466 §1); Home is the account's home.
 	Run               forgekey.Runner
 	Home, Work, Cache string
+	// RemoteBase is where repositories are fetched from, "ssh://mesh-forge/" when empty; FetchOptions are the options of
+	// the SDK's fetch and merge. A test points them at a local repository (buildstep.AllowFileRemote).
+	RemoteBase   string
+	FetchOptions []buildstep.Option
 	// HTTP fetches the files an archive artifact is pinned to (url and sha256); a client of its own with a fifteen-minute
 	// timeout when nil. A test serves its own.
 	HTTP *http.Client

modules/mesh-build-go/cmd/mesh-build-go/pins.go

@@ -0,0 +1,175 @@
+package main
+
+// Pins on a pull request's head (novox/hq ADR 0482 §2, ADR 0500 §2; issue 1148): a group's Go members pin the head of
+// the group's mesh-sdk pull request, a commit that only refs/pull/<n>/head of the forge carries until the merge. Go
+// cannot fetch it by its pseudo-version, so a fetch that meets "unknown revision" for such a pin finds the commit among
+// the forge's pull request heads, places that repository beside the workspace as a plain directory, and hands it to
+// Go through a temporary -modfile, a copy of the directory's go.mod that replaces the module by that directory. The
+// fetch's go commands and the build use the same modfile, and the build still runs with GOPROXY=off. A pin Go can
+// fetch is not touched, and a directory that vendors is never resolved.
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strings"
+)
+
+const forgePrefix = "git.novox.be/novox/"
+
+var pseudoVersion = regexp.MustCompile(`[-.][0-9]{14}-([0-9a-f]{12})$`)
+
+// pin is a requirement of a go.mod on a commit of a repository of the forge, by a pseudo-version.
+type pin struct {
+	module string // git.novox.be/novox/<repository>[/<directory of the module in it>]
+	repo   string // <repository>
+	sub    string // the module's directory in the repository, "" for its root
+	short  string // the 12 digits of the commit the pseudo-version ends in
+}
+
+// forgePins are the pseudo-version requirements of a go.mod on the forge's own modules.
+func forgePins(gomod string) []pin {
+	var pins []pin
+	for _, line := range strings.Split(gomod, "\n") {
+		if i := strings.Index(line, "//"); i >= 0 {
+			line = line[:i]
+		}
+		f := strings.Fields(line)
+		if len(f) > 0 && f[0] == "require" {
+			f = f[1:]
+		}
+		if len(f) != 2 || !strings.HasPrefix(f[0], forgePrefix) {
+			continue
+		}
+		v := pseudoVersion.FindStringSubmatch(f[1])
+		if v == nil {
+			continue
+		}
+		parts := strings.SplitN(strings.TrimPrefix(f[0], forgePrefix), "/", 2)
+		p := pin{module: f[0], repo: parts[0], short: v[1]}
+		if len(parts) == 2 {
+			p.sub = parts[1]
+		}
+		pins = append(pins, p)
+	}
+	return pins
+}
+
+// pinsDir is where the temporary modfile of a module directory of a workspace lies: the workspace's pins directory,
+// by the directory's path in the tree. dir is outside any workspace of the work directory, and the answer empty, when
+// it does not lie in <work>/<workspace>/tree.
+func (m *Module) pinsDir(dir string) string {
+	rel, err := filepath.Rel(m.Work, dir)
+	if err != nil {
+		return ""
+	}
+	parts := strings.Split(filepath.ToSlash(rel), "/")
+	if len(parts) < 2 || parts[0] == ".." || parts[1] != "tree" {
+		return ""
+	}
+	name := strings.Join(parts[2:], "_")
+	if name == "" {
+		name = "root"
+	}
+	return filepath.Join(m.Work, parts[0], "pins", name)
+}
+
+// pinModfile is the modfile handed to Go for dir, and whether there is one: only a directory a fetch resolved a pin
+// for has it.
+func (m *Module) pinModfile(dir string) (string, bool) {
+	p := m.pinsDir(dir)
+	if p == "" {
+		return "", false
+	}
+	p = filepath.Join(p, "go.mod")
+	_, err := os.Stat(p)
+	return p, err == nil
+}
+
+// resolvePins resolves the pins of dir that a go command failed on: those whose commit the failure names. It answers
+// false when there is none, and the failure is then the caller's.
+func (m *Module) resolvePins(ctx context.Context, root, dir, failure string) (bool, error) {
+	raw, err := os.ReadFile(filepath.Join(dir, "go.mod"))
+	if err != nil {
+		return false, nil
+	}
+	modfile, _ := m.pinModfile(dir)
+	done := ""
+	if modfile != "" {
+		if b, err := os.ReadFile(modfile); err == nil {
+			done = string(b)
+		}
+	}
+	progress := false
+	for _, p := range forgePins(string(raw)) {
+		if !strings.Contains(failure, p.short) || strings.Contains(done, "replace "+p.module+" =>") {
+			continue
+		}
+		where, err := m.placePin(ctx, root, p, failure)
+		if err != nil {
+			return false, err
+		}
+		if err := m.replaceInModfile(dir, p.module, where); err != nil {
+			return false, err
+		}
+		progress = true
+	}
+	return progress, nil
+}
+
+// placePin finds the commit of a pin among the pull request heads of the forge, places the repository at it beside
+// the workspace (the way a fetch places a sibling) and answers the directory of the module in it.
+func (m *Module) placePin(ctx context.Context, root string, p pin, failure string) (string, error) {
+	repository := "novox/" + p.repo
+	r := m.Run(ctx, []string{"GIT_TERMINAL_PROMPT=0"}, "git", "-c", "credential.helper=", "ls-remote", m.remote(repository), "refs/pull/*/head")
+	if r.Status != 0 || r.Err != "" {
+		return "", fmt.Errorf("the pin of %s at commit %s: listing the pull requests of %s: %s", p.module, p.short, repository, firstLine(r.Err+" "+r.Stderr))
+	}
+	commit, ref := "", ""
+	for _, l := range strings.Split(r.Stdout, "\n") {
+		if sha, name, ok := strings.Cut(strings.TrimSpace(l), "\t"); ok && commitOK.MatchString(sha) && strings.HasPrefix(sha, p.short) && strings.HasSuffix(name, "/head") {
+			commit, ref = sha, name
+			break
+		}
+	}
+	if commit == "" {
+		return "", fmt.Errorf("the pin of %s at commit %s is on no pull request head of %s on the forge; go said: %s", p.module, p.short, repository, causeLine(failure))
+	}
+	// One placement per repository and commit, shared by every go.mod directory of the tree that pins it.
+	at := filepath.Join(root, "pinned", p.repo+"@"+commit)
+	where := filepath.Join(at, "beside", p.repo, filepath.FromSlash(p.sub))
+	if _, err := os.Stat(filepath.Join(at, "beside", p.repo)); err == nil {
+		return where, nil
+	}
+	if _, err := m.placeSiblings(ctx, at, []siblingArg{{repository: repository, commit: commit, ref: ref}}); err != nil {
+		return "", fmt.Errorf("the pin of %s at commit %s: %w", p.module, p.short, err)
+	}
+	return where, nil
+}
+
+// replaceInModfile adds `replace module => where` to the temporary modfile of dir, made from the directory's go.mod and
+// go.sum the first time; Go reads the sums beside the modfile.
+func (m *Module) replaceInModfile(dir, module, where string) error {
+	pins := m.pinsDir(dir)
+	if pins == "" {
+		return fmt.Errorf("the directory %s lies outside a workspace", dir)
+	}
+	if err := os.MkdirAll(pins, 0o700); err != nil {
+		return err
+	}
+	modfile := filepath.Join(pins, "go.mod")
+	body, err := os.ReadFile(modfile)
+	if err != nil {
+		if body, err = os.ReadFile(filepath.Join(dir, "go.mod")); err != nil {
+			return err
+		}
+		sum, _ := os.ReadFile(filepath.Join(dir, "go.sum"))
+		if err := os.WriteFile(filepath.Join(pins, "go.sum"), sum, 0o600); err != nil {
+			return err
+		}
+	}
+	body = append(body, []byte("\nreplace "+module+" => "+where+"\n")...)
+	return os.WriteFile(modfile, body, 0o600)
+}

modules/mesh-build-go/cmd/mesh-build-go/pins_integration_test.go

@@ -0,0 +1,59 @@
+//go:build integration
+
+package main
+
+// A pin on a pull request's head, on real git repositories and the real go (issue 1148); pins_test.go proves the
+// commands with a fake runner.
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"testing"
+
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+)
+
+// 1148/AC2: given a forge with a mesh-sdk-like pull request whose branch is deleted (only refs/pull/7/head carries its
+// commit) and a Go member pinning that head by a pseudo-version, when build_go_fetch then build_go_build run on the
+// member, then both pass, the build with GOPROXY=off.
+func TestRealFetchAndBuildOfAMemberPinningAPullHead(t *testing.T) {
+	// Not skipped when a tool is missing: a pass of the check must mean this test ran (the check prints no test log).
+	for _, tool := range []string{"go", "git"} {
+		if _, err := exec.LookPath(tool); err != nil {
+			t.Fatalf("no %s where this check runs: the pin on a pull request's head cannot be proven", tool)
+		}
+	}
+	f := newForge(t)
+	work, fork := f.repo("novox/dep", map[string]string{"README": "dep\n"})
+	head := f.commit("novox/dep", work, fork, map[string]string{
+		"go/go.mod": "module git.novox.be/novox/dep/go\n\ngo 1.25.0\n",
+		"go/dep.go": "package dep\n\n// Name is what the member prints.\nconst Name = \"from the pull request\"\n",
+	}, "refs/pull/7/head")
+	git(t, work, "checkout", "-q", "main") // no branch of the repository carries the head
+	member := map[string]string{
+		"go.mod": "module fixture/member\n\ngo 1.25.0\n\nrequire git.novox.be/novox/dep/go v0.0.0-20261022120000-" + head[:12] + "\n",
+		"cmd/prog/main.go": "package main\n\nimport (\n\t\"fmt\"\n\n\tdep \"git.novox.be/novox/dep/go\"\n)\n\n" +
+			"func main() { fmt.Println(dep.Name) }\n",
+		"module.json": `{"module":"fixture-member","version":"1","build":{"artifacts":[{"name":"tools","kind":"bundle","language":"go","system":"arch","from":"cmd/prog","binary":"prog-bin","loads":["prog-bin"]}]}}`,
+	}
+	_, memberHead := f.repo("novox/member", member)
+	m, states := f.module(t)
+
+	res, st := fetched(t, m, states, map[string]any{"repository": "novox/member", "commit": memberHead})
+	if st.State != delivery.StepPassed {
+		t.Fatalf("the fetch ended %s: %s", st.State, st.Reason)
+	}
+	if _, err := os.Stat(filepath.Join(m.Work, res.Workspace, "pinned", "dep@"+head, "beside", "dep", "go", "dep.go")); err != nil {
+		t.Errorf("the pull request's repository was not placed beside the workspace: %v", err)
+	}
+	built, err := m.build(context.Background(), map[string]any{"workspace": res.Workspace, "module": ".", "artifact": "tools"})
+	if err != nil {
+		t.Fatal(fmt.Errorf("the build: %w", err))
+	}
+	if b := built.(BuildResult); b.Digest == "" || b.Binary != "prog-bin" {
+		t.Errorf("the build answered %+v", b)
+	}
+}

modules/mesh-build-go/cmd/mesh-build-go/pins_test.go

@@ -0,0 +1,246 @@
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+	"git.novox.be/novox/mesh-sdk/go/forgekey"
+)
+
+// pinShort is the 12 digits of commitSHA a pseudo-version ends in.
+const pinShort = "0123456789ab"
+
+const pinnedGoMod = "module fixture/member\n\ngo 1.26\n\nrequire (\n\tgit.novox.be/novox/mesh-sdk/go v0.1.15-0.20261022120000-" + pinShort + "\n)\n"
+
+// pinHarness runs a fetch of a tree whose only go.mod is gomod (a vendoring one when vendor is set) against a runner
+// that stands for the forge and for go: a pull request's head is listed by ls-remote when pulls says so, and go mod
+// download of a pseudo-version that no ref carries fails with "unknown revision" unless the command was handed a
+// -modfile.
+type pinHarness struct {
+	t       *testing.T
+	m       *Module
+	f       *fakeStep
+	pulls   string // what git ls-remote answers
+	onTrunk bool   // the pin is fetchable as it is: go mod download never says unknown revision
+	cmds    []cmdRecord
+}
+
+func newPinHarness(t *testing.T, gomod string, vendor bool, pulls string) (*pinHarness, *keptStates) {
+	f := &fakeStep{gomods: "go.mod\n"}
+	m, states := fetchModule(t, f)
+	h := &pinHarness{t: t, m: m, f: f, pulls: pulls}
+	m.Run = func(ctx context.Context, env []string, name string, args ...string) forgekey.Ran {
+		line := name + " " + strings.Join(args, " ")
+		h.cmds = append(h.cmds, cmdRecord{env: env, line: line})
+		switch {
+		case name == "git" && strings.Contains(line, " checkout ") && !strings.Contains(line, "pinned"):
+			for i, a := range args {
+				if a == "-C" {
+					os.MkdirAll(args[i+1], 0o755)
+					for _, g := range strings.Fields(f.gomods) {
+						d := filepath.Join(args[i+1], filepath.Dir(g))
+						os.MkdirAll(d, 0o755)
+						os.WriteFile(filepath.Join(d, "go.mod"), []byte(gomod), 0o644)
+						os.WriteFile(filepath.Join(d, "go.sum"), []byte("sum\n"), 0o644)
+					}
+					if vendor {
+						os.MkdirAll(filepath.Join(args[i+1], "vendor"), 0o755)
+						os.WriteFile(filepath.Join(args[i+1], "vendor", "modules.txt"), nil, 0o644)
+					}
+				}
+			}
+		case name == "git" && strings.Contains(line, "ls-remote"):
+			return forgekey.Ran{Stdout: h.pulls}
+		case name == "go" && strings.Contains(line, " mod download"):
+			if !h.onTrunk && !strings.Contains(strings.Join(env, " "), "-modfile=") {
+				return forgekey.Ran{Status: 1, Stderr: "go: git.novox.be/novox/mesh-sdk/go@v0.1.15-0.20261022120000-" + pinShort + ": invalid version: unknown revision " + pinShort + "\n"}
+			}
+		}
+		return f.run(ctx, env, name, args...)
+	}
+	return h, states
+}
+
+func (h *pinHarness) fetch(states *keptStates) (FetchResult, delivery.Step) {
+	h.t.Helper()
+	if _, err := fetchTool(h.t, h.m)(fetchArgs); err != nil {
+		h.t.Fatal(err)
+	}
+	st := states.waitEnd(h.t)
+	var res FetchResult
+	if st.State == delivery.StepPassed {
+		json.Unmarshal(st.Result, &res)
+	}
+	return res, st
+}
+
+func (h *pinHarness) ran(sub string) bool {
+	for _, c := range h.cmds {
+		if strings.Contains(c.line, sub) {
+			return true
+		}
+	}
+	return false
+}
+
+const pullList = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\trefs/pull/6/head\n" + commitSHA + "\trefs/pull/7/head\n"
+
+// 1148/AC1: a go.mod requiring mesh-sdk at a pseudo-version only a pull request's head carries is fetched: the
+// repository is placed beside the workspace at that commit, go mod download and verify succeed through a temporary
+// -modfile replacing the module by that directory, and the build is handed the same -modfile with GOPROXY=off.
+func TestAPinOnAPullHeadIsPlacedBesideAndHandedToGoByAModfile(t *testing.T) {
+	h, states := newPinHarness(t, pinnedGoMod, false, pullList)
+	res, st := h.fetch(states)
+	if st.State != delivery.StepPassed {
+		t.Fatalf("the step ended %s: %s", st.State, st.Reason)
+	}
+	placed := filepath.Join(h.m.Work, res.Workspace, "pinned", "mesh-sdk@"+commitSHA, "beside", "mesh-sdk")
+	if !h.ran("-C " + placed + " checkout -q --detach " + commitSHA) {
+		t.Errorf("mesh-sdk was not placed at %s at the commit:\n%s", placed, strings.Join(h.f.lines(), "\n"))
+	}
+	if !h.ran("refs/pull/*/head") {
+		t.Errorf("the forge's pull request heads were not listed")
+	}
+	dir := filepath.Join(h.m.Work, res.Workspace, "tree")
+	flags := ""
+	for _, e := range h.m.goEnvFor(dir) {
+		if strings.HasPrefix(e, "GOFLAGS=") {
+			flags = e
+		}
+	}
+	_, modfile, ok := strings.Cut(flags, "-modfile=")
+	if !ok {
+		t.Fatalf("go is not handed a -modfile: %v", h.m.goEnvFor(dir))
+	}
+	raw, err := os.ReadFile(strings.Fields(modfile)[0])
+	if err != nil {
+		t.Fatal(err)
+	}
+	if want := "replace git.novox.be/novox/mesh-sdk/go => " + filepath.Join(placed, "go"); !strings.Contains(string(raw), want) || !strings.Contains(string(raw), "module fixture/member") {
+		t.Errorf("the modfile lacks %q:\n%s", want, raw)
+	}
+	build := strings.Join(h.m.buildEnv(dir), " ")
+	if !strings.Contains(build, "-modfile="+strings.Fields(modfile)[0]) || !strings.Contains(build, "GOPROXY=off") {
+		t.Errorf("the build is not handed the modfile with GOPROXY=off: %s", build)
+	}
+	if !h.ran(" mod verify") {
+		t.Errorf("go mod verify did not run")
+	}
+}
+
+// 1148/AC3: a pin go downloads as it is (on the trunk or a tag) behaves as today: no listing of pull requests, no
+// repository placed, no -modfile in the fetch or the build.
+func TestAPinGoCanDownloadIsLeftAsToday(t *testing.T) {
+	h, states := newPinHarness(t, pinnedGoMod, false, pullList)
+	h.onTrunk = true
+	res, st := h.fetch(states)
+	if st.State != delivery.StepPassed {
+		t.Fatalf("the step ended %s: %s", st.State, st.Reason)
+	}
+	if h.ran("ls-remote") || h.ran("pinned") {
+		t.Errorf("a pin on the trunk made the fetch look for a pull request or place a repository:\n%s", strings.Join(h.f.lines(), "\n"))
+	}
+	dir := filepath.Join(h.m.Work, res.Workspace, "tree")
+	for _, e := range append(h.m.goEnvFor(dir), h.m.buildEnv(dir)...) {
+		if strings.Contains(e, "-modfile") {
+			t.Errorf("a -modfile is handed to go: %s", e)
+		}
+	}
+	if !h.ran(" mod download") || !h.ran(" mod verify") {
+		t.Errorf("go mod download and verify did not run as before")
+	}
+}
+
+// 1148/AC4: a pin that no ref of the forge carries ends the step failed, naming the module and the commit.
+func TestAPinOnNoRefFailsNamingTheModuleAndTheCommit(t *testing.T) {
+	h, states := newPinHarness(t, pinnedGoMod, false, "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\trefs/pull/6/head\n")
+	_, st := h.fetch(states)
+	if st.State != delivery.StepFailed {
+		t.Fatalf("the step ended %s, want failed", st.State)
+	}
+	if !strings.Contains(st.Reason, "no pull request head") || !strings.Contains(st.Reason, "unknown revision") ||
+		!strings.Contains(st.Reason, "git.novox.be/novox/mesh-sdk/go") || !strings.Contains(st.Reason, pinShort) {
+		t.Errorf("the reason does not name the module and the commit: %q", st.Reason)
+	}
+	if !h.ran("ls-remote") {
+		t.Errorf("the forge's pull request heads were never looked at")
+	}
+}
+
+// 1148/AC5: a directory that vendors resolves nothing: no go command, no listing, no repository placed.
+func TestAVendoringDirectoryResolvesNothing(t *testing.T) {
+	h, states := newPinHarness(t, pinnedGoMod, true, pullList)
+	_, st := h.fetch(states)
+	if st.State != delivery.StepPassed {
+		t.Fatalf("the step ended %s: %s", st.State, st.Reason)
+	}
+	if h.ran("go -C") || h.ran("ls-remote") || h.ran("pinned") {
+		t.Errorf("a vendoring directory was resolved:\n%s", strings.Join(h.f.lines(), "\n"))
+	}
+}
+
+// 1148/AC1 (a repository with several go.mod directories, as mesh-catalog has): two directories pinning the same pull
+// head share one placement and both are handed a modfile; the fetch does not fail placing it twice.
+func TestTwoDirectoriesPinningOneHeadShareOnePlacement(t *testing.T) {
+	h, states := newPinHarness(t, pinnedGoMod, false, pullList)
+	h.f.gomods = "go.mod\nsub/go.mod\n"
+	res, st := h.fetch(states)
+	if st.State != delivery.StepPassed {
+		t.Fatalf("the step ended %s: %s", st.State, st.Reason)
+	}
+	checkouts := 0
+	for _, c := range h.cmds {
+		if strings.Contains(c.line, "pinned") && strings.Contains(c.line, " checkout ") {
+			checkouts++
+		}
+	}
+	if checkouts != 1 {
+		t.Errorf("the repository was placed %d times, want once:\n%s", checkouts, strings.Join(h.f.lines(), "\n"))
+	}
+	for _, d := range []string{"tree", "tree/sub"} {
+		if _, ok := h.m.pinModfile(filepath.Join(h.m.Work, res.Workspace, d)); !ok {
+			t.Errorf("%s was not handed a modfile", d)
+		}
+	}
+}
+
+// 1148/AC1: two directories pinning two different commits of one repository get two placements, each its own.
+func TestTwoCommitsOfOneRepositoryGetTwoPlacements(t *testing.T) {
+	other := "fedcba9876543210fedcba9876543210fedcba98"
+	h, states := newPinHarness(t, pinnedGoMod, false, commitSHA+"\trefs/pull/7/head\n"+other+"\trefs/pull/8/head\n")
+	h.f.gomods = "go.mod\nsub/go.mod\n"
+	base := h.m.Run
+	h.m.Run = func(ctx context.Context, env []string, name string, args ...string) forgekey.Ran {
+		if name == "git" && strings.Contains(strings.Join(args, " "), "pinned/mesh-sdk@"+other+"/") && strings.Contains(strings.Join(args, " "), " rev-parse HEAD") {
+			return forgekey.Ran{Stdout: other + "\n"}
+		}
+		// the second directory pins the other commit
+		if name == "git" && strings.Contains(strings.Join(args, " "), " checkout ") && !strings.Contains(strings.Join(args, " "), "pinned") {
+			r := base(ctx, env, name, args...)
+			for i, a := range args {
+				if a == "-C" {
+					os.WriteFile(filepath.Join(args[i+1], "sub", "go.mod"), []byte(strings.ReplaceAll(pinnedGoMod, pinShort, other[:12])), 0o644)
+				}
+			}
+			return r
+		}
+		if name == "go" && strings.Contains(strings.Join(args, " "), "/sub mod download") && !strings.Contains(strings.Join(env, " "), "-modfile=") {
+			return forgekey.Ran{Status: 1, Stderr: "go: git.novox.be/novox/mesh-sdk/go@v0.1.15-0.20261022120000-" + other[:12] + ": invalid version: unknown revision " + other[:12] + "\n"}
+		}
+		return base(ctx, env, name, args...)
+	}
+	_, st := h.fetch(states)
+	if st.State != delivery.StepPassed {
+		t.Fatalf("the step ended %s: %s", st.State, st.Reason)
+	}
+	for _, c := range []string{commitSHA, other} {
+		if !h.ran("pinned/mesh-sdk@" + c) {
+			t.Errorf("no placement of mesh-sdk at %s", c)
+		}
+	}
+}

modules/mesh-build-go/cmd/mesh-build-go/preview.go

@@ -0,0 +1,120 @@
+package main
+
+// The merge preview and the siblings of a fetch (novox/hq ADR 0484 clauses 3 and 4; issues 1675 and 1677). The merge
+// itself is the SDK's (buildstep.MergeInto), the one every build module's fetch step makes; what is here is the answer
+// built from it and the placing of the sibling repositories the tests read.
+
+import (
+	"context"
+	"fmt"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"sort"
+	"strings"
+
+	"git.novox.be/novox/mesh-sdk/go/buildstep"
+)
+
+// Sibling is a repository placed beside the fetched tree: its name (the directory under beside/) and its commit.
+type Sibling struct {
+	Repository string `json:"repository"`
+	Commit     string `json:"commit"`
+	Dir        string `json:"dir"`
+}
+
+// remote is the address a repository is fetched from: the forge over ssh as the account, or RemoteBase when a test set it.
+func (m *Module) remote(repository string) string {
+	base := m.RemoteBase
+	if base == "" {
+		base = "ssh://" + ForgeAlias + "/"
+	}
+	return base + repository + ".git"
+}
+
+// merge makes the merge preview of the head onto base and writes the answer into res.
+func (m *Module) merge(ctx context.Context, res *FetchResult, tree, remote, base, commit string) error {
+	mr, err := buildstep.MergeInto(ctx, m.Run, tree, remote, base, commit, m.FetchOptions...)
+	if err != nil {
+		return err
+	}
+	res.Base = mr.Base
+	res.Conflicts, res.Merge, res.Changed = mr.Conflicts, mr.Merge, mr.Changed
+	if res.Merge == "" {
+		return nil
+	}
+	res.Trees, err = buildstep.ModuleTrees(ctx, m.Run, nil, tree, res.Merge)
+	return err
+}
+
+// ref is the pull request head carrying the commit, when only it does (a pin on a pull request, issue 1148).
+type siblingArg struct{ repository, commit, ref string }
+
+func siblingsArg(v any) ([]siblingArg, error) {
+	if v == nil {
+		return nil, nil
+	}
+	list, ok := v.([]any)
+	if !ok {
+		return nil, fmt.Errorf("beside is a list of {repository, commit}")
+	}
+	var out []siblingArg
+	seen := map[string]bool{}
+	for _, e := range list {
+		o, _ := e.(map[string]any)
+		repository, _ := o["repository"].(string)
+		commit, _ := o["commit"].(string)
+		if !repositoryOK.MatchString(repository) || strings.Contains(repository, "..") {
+			return nil, fmt.Errorf("beside: %q is not a repository, <owner>/<name>", repository)
+		}
+		if !commitOK.MatchString(commit) {
+			return nil, fmt.Errorf("beside: %q is not a full commit (40 hex digits)", commit)
+		}
+		name := repository[strings.Index(repository, "/")+1:]
+		if seen[name] {
+			return nil, fmt.Errorf("beside: two repositories are named %s", name)
+		}
+		seen[name] = true
+		out = append(out, siblingArg{repository: repository, commit: commit})
+	}
+	return out, nil
+}
+
+// BesideDir is where a workspace's siblings are placed, and what MESH_CHECK_BESIDE names.
+func (m *Module) besideDir(workspace string) string {
+	return filepath.Join(m.Work, workspace, "beside")
+}
+
+// placeSiblings fetches each sibling into beside/<name> of the workspace root, as a plain directory. A symlink anywhere
+// in a placed tree fails the step naming it: the mesh creates none, and a test must not be led out of its sibling.
+func (m *Module) placeSiblings(ctx context.Context, root string, siblings []siblingArg) ([]Sibling, error) {
+	var placed []Sibling
+	for _, s := range siblings {
+		name := s.repository[strings.Index(s.repository, "/")+1:]
+		dir := filepath.Join(root, "beside", name)
+		if err := os.MkdirAll(dir, 0o700); err != nil {
+			return nil, err
+		}
+		if err := buildstep.FetchCommit(ctx, m.Run, dir, m.remote(s.repository), s.commit, s.ref, m.FetchOptions...); err != nil {
+			return nil, fmt.Errorf("beside %s: %w", s.repository, err)
+		}
+		if link := firstSymlink(dir); link != "" {
+			return nil, fmt.Errorf("beside %s holds a symlink, %s", s.repository, link)
+		}
+		placed = append(placed, Sibling{Repository: s.repository, Commit: s.commit, Dir: name})
+	}
+	sort.Slice(placed, func(i, j int) bool { return placed[i].Dir < placed[j].Dir })
+	return placed, nil
+}
+
+func firstSymlink(dir string) string {
+	var found string
+	filepath.WalkDir(dir, func(p string, d fs.DirEntry, err error) error {
+		if err == nil && d.Type()&fs.ModeSymlink != 0 && found == "" {
+			found, _ = filepath.Rel(dir, p)
+			return fs.SkipAll
+		}
+		return nil
+	})
+	return found
+}

modules/mesh-build-go/cmd/mesh-build-go/preview_integration_test.go

@@ -0,0 +1,228 @@
+//go:build integration
+
+package main
+
+// The fetch step's merge and siblings on real git repositories and the real go (issues 1675 and 1677): they start
+// processes, so they carry the tag; preview_test.go proves the commands with a fake runner.
+
+import (
+	"encoding/json"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"testing"
+	"time"
+
+	"git.novox.be/novox/mesh-sdk/go/buildstep"
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+)
+
+func git(t *testing.T, dir string, args ...string) string {
+	t.Helper()
+	cmd := exec.Command("git", append([]string{"-C", dir, "-c", "user.name=t", "-c", "user.email=t@example.invalid", "-c", "commit.gpgsign=false"}, args...)...)
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		t.Fatalf("git %v: %v\n%s", args, err, out)
+	}
+	return strings.TrimSpace(string(out))
+}
+
+func put(t *testing.T, dir, name, body string) {
+	t.Helper()
+	p := filepath.Join(dir, name)
+	if err := os.MkdirAll(filepath.Dir(p), 0o755); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(p, []byte(body), 0o644); err != nil {
+		t.Fatal(err)
+	}
+}
+
+// forge is a directory of bare repositories <owner>/<name>.git standing in for the forge, and a module fetching from it.
+type forge struct {
+	t    *testing.T
+	root string
+}
+
+func newForge(t *testing.T) *forge { return &forge{t: t, root: t.TempDir()} }
+
+// repo makes the repository owner/name with the files on main and answers its work directory and the commit.
+func (f *forge) repo(name string, files map[string]string) (work, commit string) {
+	bare := filepath.Join(f.root, "forge", name+".git")
+	work = filepath.Join(f.root, "work", name)
+	os.MkdirAll(bare, 0o755)
+	os.MkdirAll(work, 0o755)
+	git(f.t, bare, "init", "-q", "--bare")
+	git(f.t, work, "init", "-q", "-b", "main")
+	for n, c := range files {
+		put(f.t, work, n, c)
+	}
+	git(f.t, work, "add", ".")
+	git(f.t, work, "commit", "-q", "-m", "one")
+	git(f.t, work, "push", "-q", bare, "HEAD:refs/heads/main")
+	return work, git(f.t, work, "rev-parse", "HEAD")
+}
+
+// commit makes a commit off `from` in the repository's work directory and publishes it as the pull request's head.
+func (f *forge) commit(name, work, from string, files map[string]string, ref string) string {
+	git(f.t, work, "checkout", "-q", "-B", "b"+ref[len(ref)-3:], from)
+	for n, c := range files {
+		put(f.t, work, n, c)
+	}
+	git(f.t, work, "add", ".")
+	git(f.t, work, "commit", "-q", "-m", "change")
+	sha := git(f.t, work, "rev-parse", "HEAD")
+	git(f.t, work, "push", "-q", "-f", filepath.Join(f.root, "forge", name+".git"), "HEAD:"+ref)
+	return sha
+}
+
+func (f *forge) module(t *testing.T) (*Module, *keptStates) {
+	m, states := fetchModule(t, &fakeStep{})
+	m.Run = StepRunner(m.Home)
+	m.RemoteBase = "file://" + filepath.Join(f.root, "forge") + "/"
+	m.FetchOptions = []buildstep.Option{buildstep.AllowFileRemote()}
+	return m, states
+}
+
+// waitLong is waitEnd for a step that runs the real go, whose first build in a cold cache takes longer than 3 s.
+func waitLong(t *testing.T, s *keptStates) delivery.Step {
+	t.Helper()
+	select {
+	case key := <-s.ended:
+		s.mu.Lock()
+		defer s.mu.Unlock()
+		v := s.steps[key]
+		return v[len(v)-1]
+	case <-time.After(2 * time.Minute):
+		t.Fatal("the step never ended on its key")
+		return delivery.Step{}
+	}
+}
+
+func fetched(t *testing.T, m *Module, states *keptStates, args map[string]any) (FetchResult, delivery.Step) {
+	t.Helper()
+	if _, err := fetchTool(t, m)(args); err != nil {
+		t.Fatal(err)
+	}
+	st := states.waitEnd(t)
+	var res FetchResult
+	if st.State == delivery.StepPassed {
+		if err := json.Unmarshal(st.Result, &res); err != nil {
+			t.Fatal(err)
+		}
+	}
+	return res, st
+}
+
+var baseFiles = map[string]string{
+	"go.mod":                  "module fixture/m\n\ngo 1.26\n",
+	"a.txt":                   "one\ntwo\nthree\n",
+	"modules/m/module.json":   "{\"name\":\"m\"}\n",
+	"modules/m/go.sum":        "",
+	"modules/m/m.txt":         "m\n",
+	"modules/other/other.txt": "o\n",
+}
+
+// 1675/AC1 and AC2 on real git: a clean merge answers the merge commit, the changed paths (the trunk's change is not
+// among them) and the tree of each module directory, which equals git's own; a conflict is a passed step naming the files,
+// leaving the workspace at the trunk commit; and no base is today's fetch.
+func TestRealFetchMergesConflictsAndPlainlyFetches(t *testing.T) {
+	f := newForge(t)
+	work, fork := f.repo("o/r", baseFiles)
+	trunk := f.commit("o/r", work, fork, map[string]string{"modules/other/other.txt": "trunk\n", "a.txt": "one\ntwo\nTRUNK\n"}, "refs/heads/main")
+	clean := f.commit("o/r", work, fork, map[string]string{"modules/m/m.txt": "head\n"}, "refs/pull/1/head")
+	clash := f.commit("o/r", work, fork, map[string]string{"a.txt": "one\ntwo\nHEAD\n"}, "refs/pull/2/head")
+	m, states := f.module(t)
+
+	res, st := fetched(t, m, states, map[string]any{"repository": "o/r", "commit": clean, "ref": "refs/pull/1/head", "base": trunk})
+	if st.State != delivery.StepPassed || res.Merge == "" || res.Base != trunk || res.Commit != clean || len(res.Conflicts) != 0 {
+		t.Fatalf("clean: %s %s", st.State, st.Result)
+	}
+	if strings.Join(res.Changed, ",") != "modules/m/m.txt" {
+		t.Errorf("changed = %v, want the head's own change alone", res.Changed)
+	}
+	tree := res.Trees["modules/m"]
+	if want := git(t, filepath.Join(m.Work, res.Workspace, "tree"), "rev-parse", res.Merge+":modules/m"); tree.Tree != want {
+		t.Errorf("tree = %s, want %s", tree.Tree, want)
+	}
+	if tree.Manifest != sha256Hex([]byte("{\"name\":\"m\"}\n")) || tree.Locks["go.sum"] != sha256Hex(nil) {
+		t.Errorf("manifest and locks = %+v", tree)
+	}
+	if got := git(t, filepath.Join(m.Work, res.Workspace, "tree"), "rev-parse", "HEAD"); got != res.Merge {
+		t.Errorf("the workspace is at %s, want the merge %s", got, res.Merge)
+	}
+
+	res, st = fetched(t, m, states, map[string]any{"repository": "o/r", "commit": clash, "ref": "refs/pull/2/head", "base": trunk})
+	if st.State != delivery.StepPassed || res.Merge != "" || strings.Join(res.Conflicts, ",") != "a.txt" {
+		t.Fatalf("conflict: %s %s", st.State, st.Result)
+	}
+	if got := git(t, filepath.Join(m.Work, res.Workspace, "tree"), "rev-parse", "HEAD"); got != trunk {
+		t.Errorf("after a conflict the workspace is at %s, want the trunk %s", got, trunk)
+	}
+
+	res, st = fetched(t, m, states, map[string]any{"repository": "o/r", "commit": clean, "ref": "refs/pull/1/head"})
+	if st.State != delivery.StepPassed || res.Merge != "" || res.Base != "" || res.Trees != nil || len(res.Modules) != 1 {
+		t.Errorf("no base: %s %s", st.State, st.Result)
+	}
+}
+
+// 1677/AC1 on the real go: the unit level of a repository whose test reads MESH_CHECK_BESIDE fails loudly without the
+// sibling and passes with it; the sibling is a plain directory with no symlink in it; and a sibling that holds a
+// symlink fails the fetch naming it.
+func TestRealTestsReadTheSiblingBesideTheTree(t *testing.T) {
+	f := newForge(t)
+	files := map[string]string{}
+	for _, n := range []string{"go.mod", "beside.go", "beside_test.go"} {
+		raw, err := os.ReadFile(filepath.Join("testdata", "repos", "beside", n))
+		if err != nil {
+			t.Fatal(err)
+		}
+		files[n] = string(raw)
+	}
+	_, head := f.repo("o/r", files)
+	_, sibling := f.repo("o/sibling", map[string]string{"data.txt": "from the sibling\n"})
+	m, states := f.module(t)
+
+	without, _ := fetched(t, m, states, map[string]any{"repository": "o/r", "commit": head})
+	if _, err := m.testToolRun(t, without.Workspace); err != nil {
+		t.Fatal(err)
+	}
+	var res TestResult
+	st := waitLong(t, states)
+	json.Unmarshal(st.Result, &res)
+	if st.State != delivery.StepPassed || res.Passed || len(res.Failed) != 1 || !strings.Contains(res.Failed[0].Output, "MESH_CHECK_BESIDE is not set") {
+		t.Fatalf("without the sibling: %s %s", st.State, st.Result)
+	}
+
+	with, st2 := fetched(t, m, states, map[string]any{"repository": "o/r", "commit": head,
+		"beside": []any{map[string]any{"repository": "o/sibling", "commit": sibling}}})
+	if st2.State != delivery.StepPassed || len(with.Beside) != 1 {
+		t.Fatalf("with the sibling: %s %s", st2.State, st2.Result)
+	}
+	m.testToolRun(t, with.Workspace)
+	res = TestResult{}
+	st = waitLong(t, states)
+	json.Unmarshal(st.Result, &res)
+	if !res.Passed {
+		t.Errorf("with the sibling the level failed: %s", st.Result)
+	}
+	if link := firstSymlink(filepath.Join(m.Work, with.Workspace, "beside")); link != "" {
+		t.Errorf("the placed tree holds a symlink, %s", link)
+	}
+
+	_, bad := f.repo("o/linked", map[string]string{"data.txt": "x\n"})
+	work := filepath.Join(f.root, "work", "o/linked")
+	if err := os.Symlink("/etc", filepath.Join(work, "etc-link")); err != nil {
+		t.Fatal(err)
+	}
+	git(t, work, "add", ".")
+	git(t, work, "commit", "-q", "-m", "link")
+	bad = git(t, work, "rev-parse", "HEAD")
+	git(t, work, "push", "-q", "-f", filepath.Join(f.root, "forge", "o/linked.git"), "HEAD:refs/heads/main")
+	_, st3 := fetched(t, m, states, map[string]any{"repository": "o/r", "commit": head,
+		"beside": []any{map[string]any{"repository": "o/linked", "commit": bad}}})
+	if st3.State != delivery.StepFailed || !strings.Contains(st3.Reason, "etc-link") {
+		t.Errorf("a sibling with a symlink: %s %s", st3.State, st3.Reason)
+	}
+}

modules/mesh-build-go/cmd/mesh-build-go/preview_test.go

@@ -0,0 +1,317 @@
+package main
+
+import (
+	"context"
+	"crypto/sha256"
+	"encoding/hex"
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+	"git.novox.be/novox/mesh-sdk/go/forgekey"
+)
+
+const (
+	baseSHA  = "abcdef0123456789abcdef0123456789abcdef01"
+	mergeSHA = "fedcba9876543210fedcba9876543210fedcba98"
+	treeSHA  = "1111111111111111111111111111111111111111"
+)
+
+// previewRules answers the merge's commands as git does: the merge commit, the changed paths, the manifests, the trees.
+func previewRules(conflict bool) func(string) (forgekey.Ran, bool) {
+	merged := false
+	return func(line string) (forgekey.Ran, bool) {
+		switch {
+		case strings.Contains(line, "--is-shallow-repository"):
+			return forgekey.Ran{Stdout: "true\n"}, true
+		case strings.Contains(line, " merge --no-ff"):
+			if conflict {
+				return forgekey.Ran{Status: 1, Stderr: "CONFLICT (content): Merge conflict in a.go\n"}, true
+			}
+			merged = true
+			return forgekey.Ran{}, true
+		case strings.Contains(line, "diff --name-only --diff-filter=U"):
+			return forgekey.Ran{Stdout: "a.go\nsub/b.go\n"}, true
+		case strings.Contains(line, "diff --name-only --no-renames"):
+			return forgekey.Ran{Stdout: "a.go\nmodules/m/main.go\n"}, true
+		case strings.Contains(line, " rev-parse HEAD") && merged:
+			return forgekey.Ran{Stdout: mergeSHA + "\n"}, true
+		case strings.Contains(line, " ls-files ") && strings.Contains(line, "module.json"):
+			return forgekey.Ran{Stdout: "modules/m/module.json\n"}, true
+		case strings.Contains(line, " rev-parse "+mergeSHA+":modules/m"):
+			return forgekey.Ran{Stdout: treeSHA + "\n"}, true
+		}
+		return forgekey.Ran{}, false
+	}
+}
+
+// 1675/AC1: with a base the fetch merges the head onto it with the SDK's merge (the identity and flags of the check
+// merge, hooks off), and answers base, merge commit, changed paths and, per module directory, tree, manifest hash and lock hashes.
+func TestFetchWithABaseMergesAndAnswersThePreview(t *testing.T) {
+	f := &fakeStep{gomods: "go.mod\n", rule: previewRules(false)}
+	m, states := fetchModule(t, f)
+	m.Run = func(ctx context.Context, env []string, name string, args ...string) forgekey.Ran {
+		// the workspace's module.json and go.sum are on disk once the fake checks the head out
+		for i, a := range args {
+			if a == "-C" && len(args) > i+1 && strings.Contains(strings.Join(args, " "), " checkout ") {
+				os.MkdirAll(filepath.Join(args[i+1], "modules", "m"), 0o755)
+				os.WriteFile(filepath.Join(args[i+1], "modules", "m", "module.json"), []byte("{}\n"), 0o644)
+				os.WriteFile(filepath.Join(args[i+1], "modules", "m", "go.sum"), []byte("sum\n"), 0o644)
+			}
+		}
+		return f.run(ctx, env, name, args...)
+	}
+	args := map[string]any{"repository": "novox/mesh-sdk", "commit": commitSHA, "base": baseSHA}
+	if _, err := fetchTool(t, m)(args); err != nil {
+		t.Fatal(err)
+	}
+	st := states.waitEnd(t)
+	if st.State != delivery.StepPassed {
+		t.Fatalf("the step ended %s: %s", st.State, st.Reason)
+	}
+	var res FetchResult
+	if err := json.Unmarshal(st.Result, &res); err != nil {
+		t.Fatal(err)
+	}
+	if res.Base != baseSHA || res.Merge != mergeSHA || res.Commit != commitSHA || len(res.Conflicts) != 0 ||
+		strings.Join(res.Changed, ",") != "a.go,modules/m/main.go" {
+		t.Errorf("result = %s", st.Result)
+	}
+	mt, ok := res.Trees["modules/m"]
+	if !ok || mt.Tree != treeSHA || mt.Manifest != sha256Hex([]byte("{}\n")) || mt.Locks["go.sum"] != sha256Hex([]byte("sum\n")) {
+		t.Errorf("trees = %+v", res.Trees)
+	}
+	lines := strings.Join(f.lines(), "\n")
+	for _, want := range []string{"fetch --no-tags --unshallow origin " + baseSHA, "checkout -q --detach " + baseSHA,
+		"core.hooksPath=/dev/null", "merge --no-ff --no-edit --no-verify"} {
+		if !strings.Contains(lines, want) {
+			t.Errorf("git was not asked %q:\n%s", want, lines)
+		}
+	}
+}
+
+// 1675/AC2: a conflict is an answer: the step ends passed, the files are named, no merge commit, nothing downloaded.
+func TestFetchWithAConflictEndsPassedAndNamesTheFiles(t *testing.T) {
+	f := &fakeStep{gomods: "go.mod\n", rule: previewRules(true)}
+	m, states := fetchModule(t, f)
+	args := map[string]any{"repository": "novox/mesh-sdk", "commit": commitSHA, "base": baseSHA}
+	if _, err := fetchTool(t, m)(args); err != nil {
+		t.Fatal(err)
+	}
+	st := states.waitEnd(t)
+	if st.State != delivery.StepPassed {
+		t.Fatalf("a conflict ended the step %s: %s", st.State, st.Reason)
+	}
+	var res FetchResult
+	json.Unmarshal(st.Result, &res)
+	if res.Merge != "" || res.Base != baseSHA || strings.Join(res.Conflicts, ",") != "a.go,sub/b.go" || len(res.Changed) != 0 {
+		t.Errorf("result = %s", st.Result)
+	}
+	lines := strings.Join(f.lines(), "\n")
+	if !strings.Contains(lines, "merge --abort") || strings.Contains(lines, "mod download") {
+		t.Errorf("the merge was not undone, or modules were downloaded:\n%s", lines)
+	}
+}
+
+// 1675/AC3: no base is today's fetch: no merge, no extra command, and the answer carries none of the preview.
+func TestFetchWithoutABaseIsTodaysFetch(t *testing.T) {
+	f := &fakeStep{gomods: "go.mod\n"}
+	m, states := fetchModule(t, f)
+	fetchTool(t, m)(fetchArgs)
+	st := states.waitEnd(t)
+	lines := strings.Join(f.lines(), "\n")
+	if strings.Contains(lines, "merge") || strings.Contains(lines, "unshallow") {
+		t.Errorf("a fetch without a base merged:\n%s", lines)
+	}
+	for _, key := range []string{"base", "merge", "conflicts", "changed", "trees", "beside"} {
+		if strings.Contains(string(st.Result), `"`+key+`"`) {
+			t.Errorf("the answer carries %q without a base: %s", key, st.Result)
+		}
+	}
+}
+
+func TestABaseThatIsNotACommitIsRefusedBeforeAnythingRuns(t *testing.T) {
+	f := &fakeStep{}
+	m, states := fetchModule(t, f)
+	fetchTool(t, m)(map[string]any{"repository": "novox/mesh-sdk", "commit": commitSHA, "base": "main"})
+	if st := states.waitEnd(t); st.State != delivery.StepFailed || len(f.lines()) != 0 {
+		t.Errorf("the step ended %s after %d commands", st.State, len(f.lines()))
+	}
+}
+
+// 1677/AC1: each sibling is fetched into beside/<name> of the workspace, and the tests of the workspace are given
+// MESH_CHECK_BESIDE naming that directory, at the unit level; a workspace without siblings is given none.
+func TestSiblingsArePlacedBesideAndTheUnitLevelIsGivenTheirDirectory(t *testing.T) {
+	f := &fakeStep{gomods: "go.mod\n"}
+	m, states := fetchModule(t, f)
+	args := map[string]any{"repository": "novox/mesh-controller", "commit": commitSHA, "beside": []any{
+		map[string]any{"repository": "novox/mesh-catalog", "commit": commitSHA},
+		map[string]any{"repository": "novox/mesh-host", "commit": commitSHA}}}
+	if _, err := fetchTool(t, m)(args); err != nil {
+		t.Fatal(err)
+	}
+	st := states.waitEnd(t)
+	var res FetchResult
+	json.Unmarshal(st.Result, &res)
+	if st.State != delivery.StepPassed {
+		t.Fatalf("the step ended %s: %s", st.State, st.Reason)
+	}
+	if len(res.Beside) != 2 || res.Beside[0].Dir != "mesh-catalog" || res.Beside[1].Dir != "mesh-host" {
+		t.Fatalf("result = %s", st.Result)
+	}
+	lines := strings.Join(f.lines(), "\n")
+	for _, d := range []string{"beside/mesh-catalog", "beside/mesh-host"} {
+		if !strings.Contains(lines, filepath.Join(m.Work, res.Workspace, d)+" init") && !strings.Contains(lines, "-C "+filepath.Join(m.Work, res.Workspace, d)) {
+			t.Errorf("nothing was fetched into %s:\n%s", d, lines)
+		}
+	}
+	if !strings.Contains(lines, "remote add origin ssh://mesh-forge/novox/mesh-catalog.git") {
+		t.Errorf("the sibling was not fetched over ssh:\n%s", lines)
+	}
+
+	calls := &[]cmdRecord{}
+	m.Run = capturedRunner(t, "failing", calls)
+	if err := os.MkdirAll(filepath.Join(m.Work, res.Workspace, "tree"), 0o755); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := m.testToolRun(t, res.Workspace); err != nil {
+		t.Fatal(err)
+	}
+	states.waitEnd(t)
+	want := "MESH_CHECK_BESIDE=" + filepath.Join(m.Work, res.Workspace, "beside")
+	if !envHas(*calls, "go", want) {
+		t.Errorf("no go command was given %s", want)
+	}
+}
+
+func (m *Module) testToolRun(t *testing.T, ws string) (any, error) {
+	t.Helper()
+	for _, tool := range m.Tools(m.StepTools()) {
+		if tool.Name == "build_go_test" {
+			return tool.Run(map[string]any{"workspace": ws, "level": "unit"})
+		}
+	}
+	t.Fatal("no tool build_go_test")
+	return nil, nil
+}
+
+func envHas(calls []cmdRecord, name, want string) bool {
+	for _, c := range calls {
+		if strings.HasPrefix(c.line, name+" ") {
+			for _, e := range c.env {
+				if e == want {
+					return true
+				}
+			}
+		}
+	}
+	return false
+}
+
+func TestAWorkspaceWithoutSiblingsIsGivenNoBesideVariable(t *testing.T) {
+	m, states, ws, calls := workspaceFor(t, "failing")
+	runUnit(t, m, states, ws)
+	for _, c := range *calls {
+		for _, e := range c.env {
+			if strings.HasPrefix(e, "MESH_CHECK_BESIDE=") {
+				t.Errorf("%s was given %s", c.line, e)
+			}
+		}
+	}
+}
+
+func TestSiblingsThatAreNotRepositoriesOrCommitsAreRefused(t *testing.T) {
+	for name, beside := range map[string]any{
+		"not a list":     "x",
+		"bad repository": []any{map[string]any{"repository": "../x/y", "commit": baseSHA}},
+		"bad commit":     []any{map[string]any{"repository": "novox/a", "commit": "main"}},
+		"twice":          []any{map[string]any{"repository": "novox/a", "commit": baseSHA}, map[string]any{"repository": "other/a", "commit": baseSHA}},
+	} {
+		f := &fakeStep{}
+		m, states := fetchModule(t, f)
+		fetchTool(t, m)(map[string]any{"repository": "novox/mesh-sdk", "commit": commitSHA, "beside": beside})
+		if st := states.waitEnd(t); st.State != delivery.StepFailed || len(f.lines()) != 0 {
+			t.Errorf("%s: the step ended %s after %d commands", name, st.State, len(f.lines()))
+		}
+	}
+}
+
+// 1288/AC5 (the checker's contract): an import path runs only in the go.mod directory whose module holds it; a
+// relative pattern runs in every directory; no pattern is ./... everywhere.
+func TestPackagesRunOnlyInTheModuleThatHoldsThem(t *testing.T) {
+	tree := t.TempDir()
+	for dir, mod := range map[string]string{".": "example.org/root", "tools": "example.org/root/tools", "other": "example.org/other"} {
+		os.MkdirAll(filepath.Join(tree, dir), 0o755)
+		os.WriteFile(filepath.Join(tree, dir, "go.mod"), []byte("module "+mod+"\n\ngo 1.26\n"), 0o644)
+	}
+	dirs := []string{".", "other", "tools"}
+	got, err := packagesByDir(tree, dirs, []string{"example.org/root/a", "example.org/root/tools/b", "example.org/other"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	want := map[string]string{".": "example.org/root/a", "tools": "example.org/root/tools/b", "other": "example.org/other"}
+	for d, w := range want {
+		if strings.Join(got[d], ",") != w {
+			t.Errorf("%s runs %v, want %s", d, got[d], w)
+		}
+	}
+	got, _ = packagesByDir(tree, dirs, []string{"./x/..."})
+	if len(got["."]) != 1 || len(got["tools"]) != 1 || len(got["other"]) != 1 {
+		t.Errorf("a relative pattern = %v", got)
+	}
+	got, _ = packagesByDir(tree, dirs, nil)
+	if got["tools"][0] != "./..." {
+		t.Errorf("no pattern = %v", got)
+	}
+	if _, err := packagesByDir(tree, dirs, []string{"example.org/nowhere/x"}); err == nil || !strings.Contains(err.Error(), "example.org/nowhere/x") {
+		t.Errorf("a package no module holds: %v", err)
+	}
+}
+
+func sha256Hex(b []byte) string { h := sha256.Sum256(b); return hex.EncodeToString(h[:]) }
+
+// 1677/AC (integration level): the integration level's go test is given MESH_CHECK_BESIDE when the workspace has siblings
+// beside it, with the store's and the bus's addresses, and is given none when it has not.
+func TestTheIntegrationLevelIsGivenTheBesideDirectoryOnlyWhenSiblingsWerePlaced(t *testing.T) {
+	for _, siblings := range []bool{true, false} {
+		f := newIntegFake(t, "slow")
+		m, states := integModule(t, f)
+		beside := filepath.Join(m.Work, "ws1", "beside")
+		if siblings {
+			if err := os.MkdirAll(filepath.Join(beside, "mesh-catalog"), 0o755); err != nil {
+				t.Fatal(err)
+			}
+		}
+		if _, st := runLevelTool(t, m, states, "integration"); st.State != delivery.StepPassed {
+			t.Fatalf("the step ended %s: %s", st.State, st.Reason)
+		}
+		tested := 0
+		for _, c := range f.calls {
+			if !strings.HasPrefix(c.line, "go ") || !strings.Contains(c.line, "-tags integration") {
+				continue
+			}
+			tested++
+			got := ""
+			hasNATS := false
+			for _, e := range c.env {
+				if strings.HasPrefix(e, "MESH_CHECK_BESIDE=") {
+					got = strings.TrimPrefix(e, "MESH_CHECK_BESIDE=")
+				}
+				hasNATS = hasNATS || strings.HasPrefix(e, "MESH_TEST_NATS=")
+			}
+			want := ""
+			if siblings {
+				want = beside
+			}
+			if got != want || !hasNATS {
+				t.Errorf("siblings %v: %s was given MESH_CHECK_BESIDE=%q (want %q), MESH_TEST_NATS present %v", siblings, c.line, got, want, hasNATS)
+			}
+		}
+		if tested == 0 {
+			t.Errorf("siblings %v: no integration go test ran", siblings)
+		}
+	}
+}

modules/mesh-build-go/cmd/mesh-build-go/recipe.go

@@ -20,7 +20,7 @@ const PostgresMajor = 18
 
 // RecipeSteps is the recipe's own version: changed whenever the steps of fetch, test or build change in a way
 // that can change what they produce (ADR 0405 §7). It is one of the three values the recipe version hashes.
-const RecipeSteps = "1"
+const RecipeSteps = "2"
 
 // natsModule is the library the integration level's bus is started from (ADR 0470 §2).
 const natsModule = "github.com/nats-io/nats-server/v2"

modules/mesh-build-go/cmd/mesh-build-go/test.go

@@ -65,13 +65,23 @@ func (m *Module) test(ctx context.Context, args map[string]any) (any, error) {
 	}
 	switch level {
 	case LevelUnit:
-		return m.runLevel(ctx, tree, levelOpts{level: LevelUnit, packages: packages, bounds: Bounds{Run: m.unitBound()}})
+		return m.runLevel(ctx, tree, levelOpts{level: LevelUnit, packages: packages, bounds: Bounds{Run: m.unitBound()}, env: m.besideEnv(workspace)})
 	case LevelIntegration:
 		return m.integration(ctx, workspace, tree, packages)
 	}
 	return nil, fmt.Errorf("the level %q is neither unit nor integration", level)
 }
 
+// besideEnv is MESH_CHECK_BESIDE, naming the directory build_go_fetch placed the workspace's siblings in (ADR 0484
+// clause 4), when it placed any; the tests that read other repositories look there (mesh-sdk go/internal/beside).
+func (m *Module) besideEnv(workspace string) []string {
+	dir := m.besideDir(workspace)
+	if st, err := os.Stat(dir); err != nil || !st.IsDir() {
+		return nil
+	}
+	return []string{"MESH_CHECK_BESIDE=" + dir}
+}
+
 func packagesArg(v any) ([]string, error) {
 	if v == nil {
 		return nil, nil
@@ -115,12 +125,16 @@ func (m *Module) runLevel(ctx context.Context, tree string, o levelOpts) (*TestR
 		return nil, err
 	}
 	res := &TestResult{Level: o.level, Packages: []PackageResult{}, Setup: o.setup.Seconds(), Store: o.store, Bus: o.bus}
-	packages := o.packages
+	byDir, err := packagesByDir(tree, dirs, o.packages)
-	if len(packages) == 0 {
+	if err != nil {
-		packages = []string{"./..."}
+		return nil, err
 	}
 	began := m.clock()
 	for _, d := range dirs {
+		packages := byDir[d]
+		if len(packages) == 0 {
+			continue // no package asked for lies in this module
+		}
 		args := []string{"-C", filepath.Join(tree, d), "test", "-json", "-count=1", "-timeout", testTimeout}
 		if len(o.tags) > 0 {
 			args = append(args, "-tags", strings.Join(o.tags, ","))
@@ -141,3 +155,50 @@ func (m *Module) runLevel(ctx context.Context, tree string, o levelOpts) (*TestR
 	res.judge(o.bounds)
 	return res, nil
 }
+
+// packagesByDir says which patterns run in which go.mod directory. A relative pattern (./...) runs in every directory, as
+// it always did; an import path, as build_go_digest keys its packages, runs only in the directory whose module holds it
+// (the longest module path that is the path or its prefix), as another module's path would fail the step. No pattern
+// means ./... everywhere. An import path no module of the tree holds is an error that names it.
+func packagesByDir(tree string, dirs, patterns []string) (map[string][]string, error) {
+	out := map[string][]string{}
+	if len(patterns) == 0 {
+		patterns = []string{"./..."}
+	}
+	modules := map[string]string{}
+	for _, d := range dirs {
+		if raw, err := os.ReadFile(filepath.Join(tree, d, "go.mod")); err == nil {
+			modules[d] = modulePath(string(raw))
+		}
+	}
+	for _, p := range patterns {
+		if strings.HasPrefix(p, "./") || p == "." {
+			for _, d := range dirs {
+				out[d] = append(out[d], p)
+			}
+			continue
+		}
+		owner, best := "", -1
+		for _, d := range dirs {
+			mp := modules[d]
+			if mp != "" && (p == mp || strings.HasPrefix(p, mp+"/")) && len(mp) > best {
+				owner, best = d, len(mp)
+			}
+		}
+		if best < 0 {
+			return nil, fmt.Errorf("no module of the workspace holds the package %s", p)
+		}
+		out[owner] = append(out[owner], p)
+	}
+	return out, nil
+}
+
+// modulePath is the module path a go.mod declares, "" when it declares none.
+func modulePath(gomod string) string {
+	for _, l := range strings.Split(gomod, "\n") {
+		if f := strings.Fields(l); len(f) == 2 && f[0] == "module" {
+			return strings.Trim(f[1], `"`)
+		}
+	}
+	return ""
+}

modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/beside/beside.go

@@ -0,0 +1 @@
+package beside

modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/beside/beside_test.go

@@ -0,0 +1,22 @@
+package beside
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+// A test of a repository that reads another one, as the controller's, the node-engine's, the SDK's and the catalogue's do.
+func TestReadsTheSiblingBesideIt(t *testing.T) {
+	root := os.Getenv("MESH_CHECK_BESIDE")
+	if root == "" {
+		t.Fatal("the sibling is not beside this check: MESH_CHECK_BESIDE is not set")
+	}
+	raw, err := os.ReadFile(filepath.Join(root, "sibling", "data.txt"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	if string(raw) != "from the sibling\n" {
+		t.Fatalf("data.txt = %q", raw)
+	}
+}

modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/beside/go.mod

@@ -0,0 +1,3 @@
+module fixture/beside
+
+go 1.26

modules/mesh-build-go/go.mod

@@ -3,7 +3,7 @@ module meshbuildgo
 go 1.26.0
 
 require (
-	git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261021093645-465beb4ea5e3
+	git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261021192148-78364e318bdc
 	github.com/nats-io/nats-server/v2 v2.11.17
 )
 

modules/mesh-build-go/go.sum

@@ -1,5 +1,9 @@
 git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261021093645-465beb4ea5e3 h1:OKxU64kHN1yQ/GOa6LwoUwVmiQ74d83WMSZJRFPVm9c=
 git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261021093645-465beb4ea5e3/go.mod h1:ouERNpZizzwZ0HLEtAypsY9FR20FyUgUYRni6J7kVCY=
+git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261021185947-afbe371003a5 h1:1BiPKRPTYpgex8rSHWT9az0BteOafGWRDzd/Ba6GAcA=
+git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261021185947-afbe371003a5/go.mod h1:ouERNpZizzwZ0HLEtAypsY9FR20FyUgUYRni6J7kVCY=
+git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261021192148-78364e318bdc h1:ZJScJSnF6LgFl55/VJ9RT/lNroVWun469sXtx0nlVYw=
+git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261021192148-78364e318bdc/go.mod h1:ouERNpZizzwZ0HLEtAypsY9FR20FyUgUYRni6J7kVCY=
 github.com/antithesishq/antithesis-sdk-go v0.7.0-default-no-op h1:Z/MZK75wC/NSrkgqeNIa7jexam9uWzhLmFTSCPI/kn0=
 github.com/antithesishq/antithesis-sdk-go v0.7.0-default-no-op/go.mod h1:FQyySiasQQM8735Ddel3MRojmy4dA1IqCeyJ5jmPMbI=
 github.com/google/go-tpm v0.9.8 h1:slArAR9Ft+1ybZu0lBwpSmpwhRXaa85hWtMinMyRAWo=

modules/mesh-build-image/README.md

@@ -0,0 +1,38 @@
+# mesh-build-image — the image build module
+
+Design 47, release R4c-9 (novox/hq ADR 0487, ADR 0466 §1, ADR 0469; issue 1703). The module that builds a module's
+`image` artifact from the Dockerfile in the module's own directory, on a build machine, as an account of its own
+(`runs-as`, no login shell, home at mode 0700). It serves every module's image, whatever the base, so it is not a
+build module for one module. It claims no seat: it is assigned to the build machines and runs dark until the builder
+uses it.
+
+## Rootless
+
+The tool is `buildah`, which the `buildah` module installs and provides as `rootless-image-build` with the machine's
+reach: a machine without it refuses this module at assignment, naming `buildah`. The build runs as the module's own
+account in a user namespace (`--isolation oci`), with buildah's image store and runtime state in
+`/var/lib/mesh-build-image-store` (outside the home), no mount of the host, no container runtime socket, no registry
+credential and an environment built from scratch.
+
+The account's subordinate user and group ranges are not declared anywhere: the node-engine makes every `user` account
+with `useradd`, which allocates them. The module's health reads `/etc/subuid` and `/etc/subgid` and is unhealthy
+without a range for the account, without buildah, or when a user namespace cannot be made.
+
+The Dockerfile's steps may use the network (ADR 0487 §6); nothing a step can read holds a key.
+
+## Steps
+
+- `build_image_fetch` fetches a commit over SSH into a workspace (a base commit makes the merge preview, as the other
+  build modules' fetch). Long: answers a step id and ends on its key in `steps`.
+- `build_image_build` builds one image artifact: `buildah bud` with the Dockerfile of the module's directory as file
+  and context, `--target`, and the images `build.on` pins as `--build-arg`. Answers the image's digest. With
+  `publish: true` (a merged trunk commit only) the module's own process then pushes it to the registry under
+  `<module>/<artifact>:<tag of its own>` (the first 12 hex digits of the digest unless the call gives one), waiting out
+  a registry held still, and the key carries the digest the registry serves and the reference pinned by it. Without
+  `publish` (a pull request) nothing is pushed.
+- It refuses, naming why, an image whose build context is a whole repository (`context`) or whose `build.on` names
+  another module's artifact (`unsupportedImage` in `build.go`): those forms belong to the images build-agent builds
+  until it is removed at R4g.
+- `build_image_step`, `build_image_steps`, `build_image_status` and `build_image_health` read.
+
+The registry's address is placed into `<home>/registry` as `${seat:mesh-artifact-store:reach}` (host:port): the provisioner's client fills a moved module's placement, and the artifact store has not moved, so a `${bound:artifact-store:...}` is refused at composition (issue 1703).