buildstep: keep what one command of an ask writes into the caches for its later commands

Every command of a check ran over the shared Go build cache beneath a throwaway
tmpfs layer of its own, so the digests, the vet, the unit tests and the integration
compile of one ask each compiled every package again. With Isolation.CacheLayer a
command writes into a layer on disk of its own and Isolated moves it into the ask's
kept layer when it ends; later commands read the kept layer above the shared cache,
which stays unchanged (ADR 0541 §2, ADR 0448 §3). Empty CacheLayer keeps today's
throwaway layer. Ported from feat/try-speed S2 (issue 1921).

go/buildstep/isolate.go

@@ -3,10 +3,13 @@ package buildstep
 import (
 	"context"
 	"fmt"
+	"io/fs"
 	"os"
 	"path"
 	"path/filepath"
+	"strconv"
 	"strings"
+	"sync"
 
 	"git.novox.be/novox/mesh-sdk/go/forgekey"
 )
@@ -29,16 +32,25 @@ const Bubblewrap = "bwrap"
 //   - the Workspace and Writable directories read-write, the ReadOnly ones (the toolchain, the modules the fetch step
 //     downloaded) read-only;
 //   - the shared warm Caches read-only under a throwaway writable layer (S18), or read-write for a trunk build alone
-//     (WriteCaches), so a candidate's code never changes what a later build reads.
+//     (WriteCaches), so a candidate's code never changes what a later build reads;
+//   - with a CacheLayer, what one command writes into the caches kept for the later commands of the same ask (issue 1921,
+//     the try speed-up): the vet, the unit tests and the integration compile of one ask compile each package once.
 type Isolation struct {
 	Workspace   string
 	Writable    []string
 	ReadOnly    []string
 	Caches      []string
 	WriteCaches bool
-	Env         []string
+	// CacheLayer is a directory of the ask's own, in its workspace and gone with it: each command writes the caches into
+	// a layer of its own beneath it (overlayfs refuses an upper layer two mounts share, and an ask's commands run side by
+	// side), which Isolated moves into the ask's kept layer when the command ends; every later command reads the kept
+	// layer above the shared cache. The shared cache stays unchanged. Empty: what a command writes is thrown away.
+	CacheLayer string
+	Env        []string
 	// Hosts is the file bound as /etc/hosts; Isolated writes one naming only the loopback.
 	Hosts string
+	// run is the directory of this command's own writable layers under CacheLayer; Isolated makes one per command.
+	run string
 }
 
 // etcNeeded is what of /etc a program in the step may read: who the users are, where the libraries are, the
@@ -91,7 +103,7 @@ func (iso Isolation) command(env []string, name string, args ...string) ([]strin
 	for _, group := range []struct {
 		what string
 		dirs []string
-	}{{"writable directory", iso.Writable}, {"read-only directory", iso.ReadOnly}, {"cache", iso.Caches}} {
+	}{{"writable directory", iso.Writable}, {"read-only directory", iso.ReadOnly}, {"cache", iso.Caches}, {"cache layer", layerDirs(iso.CacheLayer)}} {
 		for _, d := range group.dirs {
 			if err := checkDir(group.what, d); err != nil {
 				return nil, err
@@ -113,7 +125,7 @@ func (iso Isolation) command(env []string, name string, args ...string) ([]strin
 	for _, d := range iso.ReadOnly {
 		argv = append(argv, "--ro-bind", d, d)
 	}
-	argv = append(argv, cacheArgs(iso.Caches, iso.WriteCaches)...)
+	argv = append(argv, iso.cacheArgs()...)
 	argv = append(argv, "--bind", iso.Workspace, iso.Workspace)
 	for _, d := range iso.Writable {
 		argv = append(argv, "--bind", d, d)
@@ -134,19 +146,107 @@ func (iso Isolation) command(env []string, name string, args ...string) ([]strin
 
 // cacheArgs binds the shared warm caches (S18): for a trunk build read-write, so the next build is warm; for any other
 // read-only beneath an overlay whose writes go to a tmpfs of the step's own, so the step writes as a build does and
-// nothing it wrote outlives it (bubblewrap's --tmp-overlay, an overlay mount in the step's user namespace).
-func cacheArgs(caches []string, write bool) []string {
+// nothing it wrote outlives it (bubblewrap's --tmp-overlay, an overlay mount in the step's user namespace). With a
+// CacheLayer the ask's kept layer lies above the shared cache and the command's writes go to its own layer on disk
+// (--overlay), which Isolated keeps for the ask when the command ends.
+func (iso Isolation) cacheArgs() []string {
 	var argv []string
-	for _, c := range caches {
-		if write {
+	for i, c := range iso.Caches {
+		switch {
+		case iso.WriteCaches:
 			argv = append(argv, "--bind", c, c)
-			continue
+		case iso.CacheLayer != "":
+			upper, work := iso.runLayer(i)
+			argv = append(argv, "--overlay-src", c, "--overlay-src", keptLayer(iso.CacheLayer, i), "--overlay", upper, work, c)
+		default:
+			argv = append(argv, "--overlay-src", c, "--tmp-overlay", c)
 		}
-		argv = append(argv, "--overlay-src", c, "--tmp-overlay", c)
 	}
 	return argv
 }
 
+func layerDirs(layer string) []string {
+	if layer == "" {
+		return nil
+	}
+	return []string{layer}
+}
+
+// keptLayer is where the ask keeps what its commands wrote into the cache i.
+func keptLayer(layer string, i int) string { return filepath.Join(layer, "kept", strconv.Itoa(i)) }
+
+// runLayer is the upper and work directory of this command's writes into the cache i. Command, which makes no
+// directory, names the layer "run"; Isolated gives each command one of its own.
+func (iso Isolation) runLayer(i int) (upper, work string) {
+	run := iso.run
+	if run == "" {
+		run = filepath.Join(iso.CacheLayer, "run")
+	}
+	return filepath.Join(run, strconv.Itoa(i), "upper"), filepath.Join(run, strconv.Itoa(i), "work")
+}
+
+// layerLocks hold one mutex per cache layer, so two commands ending at once keep their writes one after the other.
+var layerLocks sync.Map
+
+// prepareLayer makes the kept layers and a run directory of the command's own under the cache layer.
+func (iso *Isolation) prepareLayer() error {
+	if iso.CacheLayer == "" || iso.WriteCaches || len(iso.Caches) == 0 {
+		return nil
+	}
+	if err := os.MkdirAll(filepath.Join(iso.CacheLayer, "runs"), 0o700); err != nil {
+		return err
+	}
+	run, err := os.MkdirTemp(filepath.Join(iso.CacheLayer, "runs"), "run-")
+	if err != nil {
+		return err
+	}
+	iso.run = run
+	for i := range iso.Caches {
+		upper, work := iso.runLayer(i)
+		for _, d := range []string{keptLayer(iso.CacheLayer, i), upper, work} {
+			if err := os.MkdirAll(d, 0o700); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+// keepLayer moves what the command wrote into the caches into the ask's kept layers, and removes its run directory.
+// A file the command wrote replaces the kept one (a cache's newest write wins); a whiteout (a file the command
+// deleted) is not kept, since a cache entry deleted by one command is no fault of a later one. A write that cannot be
+// kept only means a later command builds it again.
+func (iso Isolation) keepLayer() {
+	if iso.run == "" {
+		return
+	}
+	defer os.RemoveAll(iso.run)
+	mu, _ := layerLocks.LoadOrStore(iso.CacheLayer, &sync.Mutex{})
+	mu.(*sync.Mutex).Lock()
+	defer mu.(*sync.Mutex).Unlock()
+	for i := range iso.Caches {
+		upper, _ := iso.runLayer(i)
+		kept := keptLayer(iso.CacheLayer, i)
+		filepath.WalkDir(upper, func(p string, d fs.DirEntry, err error) error {
+			if err != nil || p == upper {
+				return nil
+			}
+			rel, _ := filepath.Rel(upper, p)
+			to := filepath.Join(kept, rel)
+			switch {
+			case d.IsDir():
+				if fi, err := os.Lstat(to); err == nil && !fi.IsDir() {
+					os.Remove(to)
+				}
+				os.MkdirAll(to, 0o700)
+			case d.Type().IsRegular():
+				os.Rename(p, to)
+			}
+			return nil
+		})
+	}
+}
+
 // loopbackHosts is the hosts file of a step: the loopback and nothing else.
 const loopbackHosts = "127.0.0.1 localhost\n::1 localhost\n"
 
@@ -166,6 +266,10 @@ func Isolated(run forgekey.Runner, iso Isolation) forgekey.Runner {
 		}
 		iso := iso
 		iso.Hosts = hosts
+		if err := iso.prepareLayer(); err != nil {
+			return forgekey.Ran{Status: 1, Err: "the step's cache layer: " + err.Error()}
+		}
+		defer iso.keepLayer()
 		argv, err := iso.command(env, name, args...)
 		if err != nil {
 			return forgekey.Ran{Status: 1, Err: err.Error()}

go/buildstep/isolate_caches_test.go

@@ -1,6 +1,9 @@
 package buildstep
 
-import "testing"
+import (
+	"strings"
+	"testing"
+)
 
 // The shared warm caches are read under a throwaway writable layer (novox/hq ADR 0448; issue 1309): a candidate's step
 // writes into them as a build does, and nothing it writes outlives it or reaches a later build; only a trunk build
@@ -27,4 +30,35 @@ func TestACandidatesStepWritesTheCachesOnlyIntoAThrowawayLayer(t *testing.T) {
 			t.Errorf("a trunk build does not write the cache %s: %v", c, argv)
 		}
 	}
+	// 1921/S2: with a cache layer, a command reads the ask's kept layer above the shared cache and writes into a layer
+	// on disk of the ask's own, never into the shared cache and never into a throwaway tmpfs.
+	iso = Isolation{Workspace: "/w", Caches: []string{"/cache/gomod", "/cache/gobuild"}, CacheLayer: "/w/cachelayer"}
+	argv, err = iso.Command("go", "vet")
+	if err != nil {
+		t.Fatal(err)
+	}
+	for i, c := range iso.Caches {
+		if !holds(argv, "--overlay-src", c, "--overlay-src", keptLayer(iso.CacheLayer, i), "--overlay") {
+			t.Errorf("the cache %s is not read beneath the ask's kept layer: %v", c, argv)
+		}
+		if up := overlayOf(argv, c); up == "" || !strings.HasPrefix(up, "/w/cachelayer/") {
+			t.Errorf("the cache %s is written into %q, not a layer of the ask's own: %v", c, up, argv)
+		}
+		if holds(argv, "--tmp-overlay", c) || holds(argv, "--bind", c, c) {
+			t.Errorf("the cache %s is thrown away or written: %v", c, argv)
+		}
+	}
+	if _, err := (Isolation{Workspace: "/w", CacheLayer: "cachelayer"}).Command("go"); err == nil {
+		t.Error("a relative cache layer was taken")
+	}
+}
+
+// overlayOf answers the upper directory a command line gives the cache c, "" when it gives none.
+func overlayOf(argv []string, c string) string {
+	for i := 0; i+3 < len(argv); i++ {
+		if argv[i] == "--overlay" && argv[i+3] == c {
+			return argv[i+1]
+		}
+	}
+	return ""
 }

go/buildstep/isolate_integration_test.go

@@ -63,4 +63,23 @@ func TestARunStepReachesNothingAndLeavesTheCachesUnchanged(t *testing.T) {
 	if b, err := os.ReadFile(filepath.Join(workspace, "out")); r.Status != 0 || err != nil || string(b) != "built\n" {
 		t.Fatalf("the step's write to its workspace did not stay (status %d, %s%s): %q %v", r.Status, r.Stderr, r.Err, b, err)
 	}
+
+	// 1921/S2: with the ask's cache layer, what one command writes into the cache the next command of the ask reads,
+	// above what the shared cache holds, and the shared cache stays unchanged.
+	asked := Isolated(forgekey.ExecRunnerFor(0), Isolation{Workspace: workspace, Caches: []string{cacheDir},
+		CacheLayer: filepath.Join(workspace, "cachelayer")})
+	r = asked(context.Background(), []string{"PATH=/usr/bin:/bin"}, "/bin/sh", "-c", "cat "+filepath.Join(cacheDir, "warm")+" && mkdir -p "+filepath.Join(cacheDir, "ab")+" && echo compiled > "+filepath.Join(cacheDir, "ab", "one-d"))
+	if r.Status != 0 || r.Err != "" || strings.TrimSpace(r.Stdout) != "warm" {
+		t.Fatalf("the first command of the ask did not read the shared cache and write its own (status %d, %s): %s%s", r.Status, r.Err, r.Stdout, r.Stderr)
+	}
+	r = asked(context.Background(), []string{"PATH=/usr/bin:/bin"}, "/bin/cat", filepath.Join(cacheDir, "ab", "one-d"), filepath.Join(cacheDir, "warm"))
+	if r.Status != 0 || r.Err != "" || r.Stdout != "compiled\nwarm\n" {
+		t.Fatalf("the next command of the ask did not find what the first wrote (status %d, %s): %q %s", r.Status, r.Err, r.Stdout, r.Stderr)
+	}
+	if _, err := os.Stat(filepath.Join(cacheDir, "ab")); !os.IsNotExist(err) {
+		t.Fatalf("the ask's commands wrote the shared cache: %v", err)
+	}
+	if err := os.RemoveAll(filepath.Join(workspace, "cachelayer")); err != nil {
+		t.Fatalf("the ask's cache layer cannot be removed with its workspace: %v", err)
+	}
 }

go/buildstep/isolate_test.go

@@ -2,7 +2,10 @@ package buildstep
 
 import (
 	"context"
+	"os"
+	"path/filepath"
 	"strings"
+	"sync"
 	"testing"
 
 	"git.novox.be/novox/mesh-sdk/go/forgekey"
@@ -112,4 +115,55 @@ func TestIsolatedRunsEachCommandThroughBubblewrap(t *testing.T) {
 	if hosts == "" {
 		t.Fatalf("no hosts file was bound: %v", ran)
 	}
+
+	// 1921/S2: with a cache layer, what one command wrote into the caches is kept for the ask's later commands, the
+	// shared cache stays unchanged, two commands at once write into layers of their own (overlayfs refuses an upper
+	// layer two mounts share), and a command's own layer is gone when it ends.
+	root := t.TempDir()
+	shared := filepath.Join(root, "gobuild")
+	if err := os.MkdirAll(shared, 0o700); err != nil {
+		t.Fatal(err)
+	}
+	layer := filepath.Join(root, "ws", "cachelayer")
+	var mu sync.Mutex
+	uppers := map[string]bool{}
+	gate := make(chan struct{})
+	var started sync.WaitGroup
+	started.Add(2)
+	writer := func(ctx context.Context, env []string, name string, args ...string) forgekey.Ran {
+		up := overlayOf(args, shared)
+		mu.Lock()
+		uppers[up] = true
+		mu.Unlock()
+		started.Done()
+		<-gate // both commands are running before either ends
+		os.MkdirAll(filepath.Join(up, "ab"), 0o700)
+		os.WriteFile(filepath.Join(up, "ab", args[len(args)-1]+"-d"), []byte("compiled"), 0o600)
+		return forgekey.Ran{}
+	}
+	run := Isolated(writer, Isolation{Workspace: filepath.Join(root, "ws"), Caches: []string{shared}, CacheLayer: layer})
+	var wg sync.WaitGroup
+	for _, pkg := range []string{"one", "two"} {
+		wg.Add(1)
+		go func() { defer wg.Done(); run(context.Background(), nil, "go", "build", pkg) }()
+	}
+	started.Wait()
+	close(gate)
+	wg.Wait()
+	if len(uppers) != 2 {
+		t.Fatalf("two commands at once wrote into %d layers, want 2 of their own: %v", len(uppers), uppers)
+	}
+	for _, pkg := range []string{"one", "two"} {
+		if b, err := os.ReadFile(filepath.Join(keptLayer(layer, 0), "ab", pkg+"-d")); err != nil || string(b) != "compiled" {
+			t.Errorf("what the build of %s compiled is not kept for the ask: %q %v", pkg, b, err)
+		}
+	}
+	for up := range uppers {
+		if _, err := os.Stat(up); !os.IsNotExist(err) {
+			t.Errorf("the command's own layer %s outlived it: %v", up, err)
+		}
+	}
+	if entries, _ := os.ReadDir(shared); len(entries) != 0 {
+		t.Errorf("the shared cache was written: %v", entries)
+	}
 }

go/catalogue/build.go

@@ -126,7 +126,23 @@ func (m Manifest) Resolve(built []Built) (Manifest, error) {
 				continue
 			}
 			made := by[a.Name]
-			loads := BundleLoads(m, a, run)
+			// What the runtime loads: what the artifact said, else every entrypoint of a module
+			// that declares tools, else nothing (the field's own rule; see Artifact.Loads).
+			//
+			// **Never, unasked, a bundle one of the module's own resources runs** (novox/hq issue 213).
+			// A process the host runs is the module's service, not its tools: the controller declares
+			// the verbs it answers as `tools` and serves them itself, and its bundle would otherwise
+			// have been launched a second time by the node's runtime, as an MCP child it is not.
+			loads := append([]string(nil), a.Loads...)
+			if a.Loads == nil && len(m.Tools) > 0 && !run[a.Name] {
+				loads = append([]string(nil), a.Entrypoints...)
+				// A bundle compiled to a binary has no entrypoints: the binary is what it is, and what
+				// the runtime starts to serve it (novox/hq ADR 0193). So a Go tools bundle is served
+				// as Go — the runtime execs it — exactly as a TypeScript one is through its launcher.
+				if bin := BinaryOf(a); bin != "" {
+					loads = []string{bin}
+				}
+			}
 			// **Kept, never routed** (ADR 0155): the builder publishes to the store at the address
 			// it reached it by, and a manifest carrying that address names an installation —
 			// registration refused node-tools for exactly this on 2026-10-02. The build record
@@ -699,31 +715,3 @@ func undeliveredBundles(m Manifest) []string {
 	}
 	return problems
 }
-
-// BundleLoads is what the runtime loads of the bundle artifact a of m (run: the bundles one of m's own resources runs,
-// runByAResource): what the artifact said, else every entrypoint of a module that declares tools, else nothing; a
-// bundle compiled to a binary is served by its binary. The rule a build's resolution keeps on Bundle.Loads, and what a
-// module composed as what runs of it reads again when the runtime already dropped it (issue 1126).
-func BundleLoads(m Manifest, a Artifact, run map[string]bool) []string {
-	// What the runtime loads: what the artifact said, else every entrypoint of a module
-	// that declares tools, else nothing (the field's own rule; see Artifact.Loads).
-	//
-	// **Never, unasked, a bundle one of the module's own resources runs** (novox/hq issue 213).
-	// A process the host runs is the module's service, not its tools: the controller declares
-	// the verbs it answers as `tools` and serves them itself, and its bundle would otherwise
-	// have been launched a second time by the node's runtime, as an MCP child it is not.
-	loads := append([]string(nil), a.Loads...)
-	if a.Loads == nil && len(m.Tools) > 0 && !run[a.Name] {
-		loads = append([]string(nil), a.Entrypoints...)
-		// A bundle compiled to a binary has no entrypoints: the binary is what it is, and what
-		// the runtime starts to serve it (novox/hq ADR 0193). So a Go tools bundle is served
-		// as Go — the runtime execs it — exactly as a TypeScript one is through its launcher.
-		if bin := BinaryOf(a); bin != "" {
-			loads = []string{bin}
-		}
-	}
-	return loads
-}
-
-// RunByAResource is the bundles of m one of its own resources runs (its service, not its tools).
-func RunByAResource(m Manifest) map[string]bool { return runByAResource(m) }

go/catalogue/declaration.go

@@ -1103,9 +1103,6 @@ func (r Resolution) compose(with Rendering, owner map[string]string,
 		}
 		for _, unsettled := range resources {
 			if pr, ok := unsettled[HandedProvisionField].(PlanProvision); ok {
-				if handing == nil && m.Stubbed {
-					continue // held: its credential file is what runs of it, left out (issue 1126)
-				}
 				if handing == nil {
 					return nil, fmt.Errorf("%s: its credential of %s is handed to the provisioner and the module is "+
 						"not: nothing would fill it", m.Module, pr.Provision)
@@ -1130,9 +1127,6 @@ func (r Resolution) compose(with Rendering, owner map[string]string,
 				continue
 			}
 			if unsettled[HandedSecretField] != nil {
-				if handing == nil && m.Stubbed {
-					continue // held: its own secret's file is what runs of it, left out (issue 1126)
-				}
 				if handing == nil {
 					return nil, fmt.Errorf("%s: its own secret %v is handed to the provisioner and the module is "+
 						"not: nothing would fill it", m.Module, unsettled[HandedSecretField])

go/catalogue/handed_secrets_test.go

@@ -185,22 +185,6 @@ func TestAHandedModulesCredentialIssuedForItIsNamedInItsPlanAndNoValueIsSealed(t
 	if !reflect.DeepEqual(c.Plans["bot"].Provisions, want) {
 		t.Fatalf("the plan names %+v, want %+v", c.Plans["bot"].Provisions, want)
 	}
-	// Issue 1126 (novox's seed: "gitea: its credential of postgres-database is handed to the provisioner and the module
-	// is not"): held, the module is composed as its stub, with no template and no item, so nothing is handed. Its
-	// credential and its own secret are what runs of it, left out, and the composition is not refused.
-	r := forgeReader(t, true, true)
-	for i := range r.Modules {
-		if r.Modules[i].Module == "bot" {
-			h := *r.Modules[i].Handed
-			h.Templates = nil
-			r.Modules[i].Handed, r.Modules[i].Stubbed, r.Modules[i].Build = &h, true, nil
-			r.Modules[i].Resources = slices.DeleteFunc(r.Modules[i].Resources, func(x map[string]any) bool { return x["type"] != "directory" })
-		}
-	}
-	c, got = composeWith(t, r, handingTo("store:5000"))
-	if strings.Contains(got, SecretID("forge-read")) || strings.Contains(got, NeedID("token")) || c.Plans["bot"].Provisions != nil {
-		t.Fatalf("a held module's handed credential or own secret is composed: %s", got)
-	}
 }
 
 func TestACredentialIssuedForAHolderIsSealedAsBeforeWhereItsModuleIsNotHanded(t *testing.T) {

go/catalogue/manifest.go

@@ -870,11 +870,6 @@ type Manifest struct {
 	// path its manifest leaves to the mesh, a binding). Nil for any other module. Never in a manifest's JSON.
 	OwnsPaths []string `json:"-"`
 
-	// Stubbed marks a module composed as its stub (compose.Stub: held on its node, issue 1126): none of its own
-	// composition is applied, so what it hands the provisioner (a credential the vault keeps for it, its own secrets)
-	// is left out of its plan as it runs, never refused for want of a plan. Never in a manifest's JSON.
-	Stubbed bool `json:"-"`
-
 	// Jails are the fail2ban jails this module declares for its own service (novox/hq to-be 31).
 	// Written into whichever node runs the module, the same way `listens` become that node's rules.
 	Jails []Jail `json:"jails,omitempty"`

go/compose/composed.go

@@ -130,22 +130,6 @@ func compositions(in Input, node string, fps map[string]string, mode Mode, appli
 			n.Kept = kept
 		}
 	}
-	// A module composed as what runs of it contributes to the runtime what the runtime serves of it as it runs
-	// (Node.RunsTools); one of its own account is served by a runtime of its own, from its manifest as before.
-	for i := range reading.Nodes {
-		n := &reading.Nodes[i]
-		if n.Name != node || n.RunsTools == nil {
-			continue
-		}
-		kept := make(map[string]catalogue.Manifest, len(n.Kept))
-		for m, man := range n.Kept {
-			if man.Stubbed && man.RunsAs == "" {
-				man.Bundles = runningBundles(n.RunsTools[m], reading.Catalogue[m])
-			}
-			kept[m] = man
-		}
-		n.Kept = kept
-	}
 	isCarried := func(module, id string) bool {
 		if module == "" {
 			module, _ = declaration.ModuleGuess(id)
@@ -309,106 +293,6 @@ func RunsAnyOf(runs *delivery.Composed, module string) bool {
 	return false
 }
 
-// ToolsRunning is, by module, the tools bundles that run on the node (Node.RunsTools): each bundle archive a module's
-// resource unpacks at its BundlePath, with what the runtime's own process loads of it and the words it hands it
-// (catalogue.RuntimeToolModules, catalogue.RuntimeToolEnv, the mesh's own words left out). A bundle the runtime loads
-// nothing of has no Loads: the runtime dropped it, and the composition reads its loads again from the module's build
-// (issue 1126, review: shanks had already applied the drop of systemd-resolved). Nil when running holds no runtime process.
-func ToolsRunning(running []delivery.Composed) map[string][]catalogue.Bundle {
-	runtimeID := catalogue.RuntimeModule + "." + catalogue.RuntimeProcessID()
-	type resource struct {
-		ID     string            `json:"id"`
-		Module string            `json:"module"`
-		Type   string            `json:"type"`
-		Path   string            `json:"path"`
-		Source string            `json:"source"`
-		Digest string            `json:"digest"`
-		Env    map[string]string `json:"env"`
-	}
-	var env map[string]string
-	out := map[string][]catalogue.Bundle{}
-	for _, c := range running {
-		for _, raw := range c.Resources {
-			var r resource
-			if json.Unmarshal(raw, &r) != nil {
-				continue
-			}
-			owner := r.Module
-			if owner == "" {
-				owner, _ = declaration.ModuleGuess(r.ID)
-			}
-			switch {
-			case r.Type == "process" && r.ID == runtimeID && owner == catalogue.RuntimeModule:
-				env = r.Env
-			case r.Type == "archive" && owner != "" && strings.HasPrefix(r.ID, owner+"."+catalogue.BundleID("")):
-				name := strings.TrimPrefix(r.ID, owner+"."+catalogue.BundleID(""))
-				if r.Path == catalogue.BundlePath(owner, name) {
-					out[owner] = append(out[owner], catalogue.Bundle{Name: name, Source: catalogue.Recorded(r.Source), Digest: r.Digest})
-				}
-			}
-		}
-	}
-	if env == nil {
-		return nil
-	}
-	var words map[string]map[string]string
-	_ = json.Unmarshal([]byte(env[catalogue.RuntimeToolEnv]), &words)
-	for _, entry := range strings.Split(env[catalogue.RuntimeToolModules], ",") {
-		module, path, ok := strings.Cut(entry, "=")
-		if !ok || !strings.HasPrefix(path, catalogue.BundleRoot+"/"+module+"/") {
-			continue
-		}
-		name, load, ok := strings.Cut(strings.TrimPrefix(path, catalogue.BundleRoot+"/"+module+"/"), "/")
-		bundles := out[module]
-		i := slices.IndexFunc(bundles, func(b catalogue.Bundle) bool { return b.Name == name })
-		if !ok || i < 0 {
-			continue // no archive of it runs: nothing to load
-		}
-		var own map[string]string
-		for w, v := range words[module] {
-			if w == catalogue.FilesOwnedPaths || w == catalogue.ReadsSecretPlaces {
-				continue // the mesh's to say, composed again
-			}
-			if own == nil {
-				own = map[string]string{}
-			}
-			own[w] = v
-		}
-		bundles[i].Loads = append(bundles[i].Loads, load)
-		bundles[i].Env = own
-	}
-	for _, bundles := range out {
-		sort.Slice(bundles, func(i, j int) bool { return bundles[i].Name < bundles[j].Name })
-	}
-	return out
-}
-
-// runningBundles is the bundles of a module composed as what runs of it (Node.RunsTools): each that runs, with what the
-// runtime loads of it and its words; one the runtime loads nothing of takes its loads and words from the module's build
-// (man: its built bundles, else its build's artifacts, catalogue.BundleLoads), so a drop already applied is undone.
-func runningBundles(runs []catalogue.Bundle, man catalogue.Manifest) []catalogue.Bundle {
-	var out []catalogue.Bundle
-	for _, b := range runs {
-		if len(b.Loads) == 0 {
-			for _, built := range man.Bundles {
-				if built.Name == b.Name {
-					b.Loads, b.Env, b.Launchers, b.Binary = built.Loads, built.Env, built.Launchers, built.Binary
-				}
-			}
-			if man.Build != nil {
-				run := catalogue.RunByAResource(man)
-				for _, a := range man.Build.Artifacts {
-					if a.Kind == catalogue.ArtifactBundle && a.Name == b.Name {
-						b.Loads, b.Env, b.Binary = catalogue.BundleLoads(man, a, run), a.Env, catalogue.BinaryOf(a)
-					}
-				}
-			}
-		}
-		out = append(out, b)
-	}
-	return out
-}
-
 // NamesBuild says a manifest names what a build makes: its build, or a resource naming an artifact. A node cannot
 // compose such a module folded into its own composition: the build of the old form it runs is held by the controller
 // alone (issue 1126).
@@ -434,8 +318,6 @@ func Stub(m catalogue.Manifest) catalogue.Manifest {
 		m.OwnsPaths = catalogue.DeclaredPaths(m)
 	}
 	m.Build = nil
-	// What it hands the provisioner is left out as it runs, not refused for want of a plan (catalogue.Manifest.Stubbed).
-	m.Stubbed = true
 	// Nor is a template its build kept for its own files handed: a stub carries none of them (issue 1126: novox's node
 	// refused "postgres: its build kept a template for consumers, which it does not declare" with postgres held). Its
 	// items stay, and the templates they render through: a held module's contributions to other modules' collections

go/compose/composed_test.go

@@ -8,7 +8,6 @@ import (
 
 	"git.novox.be/novox/mesh-sdk/go/catalogue"
 	"git.novox.be/novox/mesh-sdk/go/delivery"
-	"git.novox.be/novox/mesh-sdk/go/overlay"
 )
 
 func fpFor(c byte) string { return delivery.SourcePrefix2 + strings.Repeat(string(c), 64) }
@@ -97,91 +96,6 @@ func TestCompositionsAreTheDeclarationSplitByModule(t *testing.T) {
 	if _, _, err := Compositions(in, "nowhere", fps, Foreseeing); err == nil {
 		t.Errorf("a node the mesh does not have was composed")
 	}
-
-	// Issue 1126, 2026-10-29: a module composed as what runs of it (folded at a build of the old form, or held) still
-	// contributes to the runtime what the runtime serves of it as it runs (Node.RunsTools): its manifest at the
-	// indexer's commit has no bundles (shanks's runtime lost the folded systemd-resolved, novox's the folded nats), and a
-	// held module's new build's bundles are not delivered.
-	dg := func(c byte) string { return "sha256:" + strings.Repeat(string(c), 64) }
-	runtime := catalogue.Manifest{Module: catalogue.RuntimeModule, Version: "1",
-		OwnSecrets: catalogue.OwnSecrets{"broker": {Path: "/var/lib/mesh/node-tools/broker"}},
-		Bundles: []catalogue.Bundle{{Name: "runtime", Source: catalogue.ArtifactStoreScheme + "node-tools/runtime/blobs/" + dg('a'),
-			Digest: dg('a'), Language: "go", Binary: "node-tools"}}}
-	store := catalogue.Manifest{Module: "artifacts", Version: "1",
-		Serves: map[string]map[string]any{catalogue.ArtifactStoreProvision: {"port": 5100}}}
-	lamp := catalogue.Manifest{Module: "lamp", Version: "1", Tools: []string{"on"},
-		Resources: []map[string]any{{"id": "state", "type": "directory", "path": "/var/lib/lamp", "mode": "0700"}},
-		Build: &catalogue.Build{Artifacts: []catalogue.Artifact{{Name: "tools", Kind: catalogue.ArtifactBundle,
-			Language: "go", System: "arch", From: "cmd/lamp-tools", Env: map[string]string{"LAMP_CONF": "/var/lib/lamp/conf"}}}}}
-	newLamp, err := lamp.Resolve([]catalogue.Built{{Name: "tools", Kind: catalogue.ArtifactBundle,
-		Reference: catalogue.ArtifactStoreScheme + "lamp/tools/blobs/" + dg('c'), Digest: dg('c')}})
-	if err != nil {
-		t.Fatal(err)
-	}
-	served := "lamp=" + catalogue.BundlePath("lamp", "tools") + "/lamp-tools"
-	runtimeRuns := func(dropped bool) delivery.Composed {
-		env := `"MESH_TOOL_MODULES":"` + served + `","MESH_TOOL_ENV":"{\"lamp\":{\"LAMP_CONF\":\"/var/lib/lamp/conf\"}}"`
-		if dropped {
-			env = `"MESH_TOOL_MODULES":""` // the drop already applied (shanks, 2026-10-29)
-		}
-		return delivery.Composed{Node: "anchor", Module: catalogue.RuntimeModule, Resources: []json.RawMessage{json.RawMessage(
-			`{"id":"node-tools.runtime","module":"node-tools","type":"process","name":"node-tools","env":{` + env + `}}`)}}
-	}
-	lampRuns := `{"id":"lamp.bundle-tools","type":"archive","source":"` + catalogue.ArtifactStoreScheme + `lamp/tools/blobs/` + dg('b') +
-		`","digest":"` + dg('b') + `","path":"` + catalogue.BundlePath("lamp", "tools") + `"}`
-	for _, row := range []struct {
-		name    string
-		set     func(n *Node) delivery.Composed // and what runs of lamp
-		fps     map[string]string
-		dropped bool
-	}{
-		{"folded at a build of the old form", func(n *Node) delivery.Composed {
-			n.InOwn = map[string]bool{"lamp": true}
-			n.RunsOwn = &delivery.Composed{Node: "anchor", Resources: []json.RawMessage{json.RawMessage(lampRuns)}}
-			return *n.RunsOwn
-		}, map[string]string{}, false},
-		{"folded, the runtime already dropped it", func(n *Node) delivery.Composed {
-			n.InOwn = map[string]bool{"lamp": true}
-			n.RunsOwn = &delivery.Composed{Node: "anchor", Resources: []json.RawMessage{json.RawMessage(lampRuns)}}
-			return *n.RunsOwn
-		}, map[string]string{}, true},
-		{"held, its new build not delivered", func(n *Node) delivery.Composed {
-			n.Held = map[string]bool{"lamp": true}
-			lr := delivery.Composed{Node: "anchor", Module: "lamp", Resources: []json.RawMessage{json.RawMessage(
-				strings.Replace(lampRuns, `"type"`, `"module":"lamp","type"`, 1))}}
-			n.Kept = map[string]catalogue.Manifest{"lamp": Carried(newLamp, "lamp", &lr)}
-			return lr
-		}, map[string]string{"lamp": fpFor('1')}, false},
-	} {
-		tools := aMesh(t)
-		tools.Catalogue[catalogue.RuntimeModule], tools.Catalogue["artifacts"], tools.Catalogue["lamp"] = runtime, store, lamp
-		anchor := nodeOf(t, &tools, "anchor")
-		anchor.Assigned = append(anchor.Assigned, "artifacts", catalogue.RuntimeModule, "lamp")
-		tools.BusMinted = []string{"anchor." + catalogue.RuntimeModule}
-		anchor.SealingKey = keyOf(t, "anchor")
-		anchor.RunsTools = ToolsRunning([]delivery.Composed{runtimeRuns(row.dropped), row.set(anchor)})
-		row.fps[overlay.Name], row.fps["artifacts"], row.fps[catalogue.RuntimeModule] = fpFor('a'), fpFor('5'), fpFor('e')
-		out, _, _, err := CompositionsIn(tools, "anchor", row.fps, Foreseeing)
-		if err != nil {
-			t.Fatalf("%s: %v", row.name, err)
-		}
-		var env map[string]any
-		for _, c := range out {
-			for _, raw := range c.Resources {
-				var r struct {
-					ID  string         `json:"id"`
-					Env map[string]any `json:"env"`
-				}
-				if json.Unmarshal(raw, &r) == nil && r.ID == "node-tools.runtime" {
-					env = r.Env
-				}
-			}
-		}
-		if env[catalogue.RuntimeToolModules] != served || env[catalogue.RuntimeToolEnv] != `{"lamp":{"LAMP_CONF":"/var/lib/lamp/conf"}}` {
-			t.Errorf("%s: the runtime serves %v with %v, want what runs of lamp, %s", row.name,
-				env[catalogue.RuntimeToolModules], env[catalogue.RuntimeToolEnv], served)
-		}
-	}
 }
 
 // 1943/AC1: the upgrade policies and sources a composition's value may name are the catalogue's own words.

go/compose/frombus/answer.go

@@ -2,8 +2,8 @@ package frombus
 
 import (
 	"context"
+	"encoding/json"
 	"fmt"
-	"maps"
 	"regexp"
 	"slices"
 	"sort"
@@ -11,6 +11,7 @@ import (
 
 	"git.novox.be/novox/mesh-sdk/go/catalogue"
 	"git.novox.be/novox/mesh-sdk/go/compose"
+	"git.novox.be/novox/mesh-sdk/go/declaration"
 	"git.novox.be/novox/mesh-sdk/go/delivery"
 )
 
@@ -71,7 +72,7 @@ func Answer(ctx context.Context, r Reader, mesh Mesh, s Scope, fps map[string]st
 			return refuse(fmt.Errorf("frombus: the credentials of %s: %w", s.Node, err))
 		}
 	}
-	composed, skipped, stood, err := composeEach(in, s.Node, fps, false, s.Running, failed, ranOf(ctx, r, mesh, s.Running, fps))
+	composed, skipped, stood, err := composeEach(in, s.Node, fps, false, s.Running, failed)
 	if err != nil {
 		// Not one module's: the node's own (a value served elsewhere, the mesh's network), said once as the node's.
 		if len(failed) == 0 {
@@ -208,24 +209,59 @@ func Answer(ctx context.Context, r Reader, mesh Mesh, s Scope, fps map[string]st
 	return a
 }
 
+// heldBehind is why a module is held with a held one it reads (composeEach's dependents).
+func heldBehind(m string) string {
+	return "it reads what " + m + " contributes or listens on, and " + m + " is held"
+}
+
+// behind is the held module a refusal's words say it is held behind, or "".
+func behind(why string) string {
+	rest, ok := strings.CutPrefix(why, "it reads what ")
+	if !ok {
+		return ""
+	}
+	m, _, ok := strings.Cut(rest, " contributes or listens on, and ")
+	if !ok || why != heldBehind(m) {
+		return ""
+	}
+	return m
+}
+
 // heldAsToday moves into Held each refusal of a module the node keeps today as it runs (Scope.HeldToday, with how:
-// held, failed, running a build of the old form): the candidate keeps it as the node does, which is no change (issue
-// 1126: a seed reproduces today, and today keeps them so). Each says how it stands today (ModuleRefused.Today). No
-// module is held behind another (issue 1960): a module that reads from a held one composes with what it last offered.
+// held, failed, running a build of the old form), and of each module held only behind one of those: the candidate keeps
+// them as the node does, which is no change (issue 1126: a seed reproduces today, and today keeps them so). Each says
+// how it stands today (ModuleRefused.Today).
 func heldAsToday(a *delivery.CandidateAnswer, today map[string]string) {
 	if len(today) == 0 {
 		return
 	}
-	kept := a.Refusals[:0]
-	for _, r := range a.Refusals {
-		if w, keep := today[r.Module]; keep {
-			r.Today = w
-			a.Held = append(a.Held, r)
-		} else {
-			kept = append(kept, r)
+	how := map[string]string{}
+	for m, w := range today {
+		how[m] = w
+	}
+	for moved := true; moved; {
+		moved = false
+		kept := a.Refusals[:0]
+		for _, r := range a.Refusals {
+			w, keep := how[r.Module]
+			if !keep {
+				if m := behind(r.Why); m != "" {
+					if _, behindKept := how[m]; behindKept {
+						w, keep = "held behind "+m, true
+					}
+				}
+			}
+			if keep {
+				r.Today = w
+				how[r.Module] = w
+				a.Held = append(a.Held, r)
+				moved = true
+			} else {
+				kept = append(kept, r)
+			}
 		}
+		a.Refusals = kept
 	}
-	a.Refusals = kept
 	if len(a.Refusals) == 0 {
 		a.Refusals = nil
 	}
@@ -276,18 +312,12 @@ func standsInFor(x, node string) (string, string) {
 // **A held module is what runs of it** (review of the apply, round 1): composed from what running holds of it
 // (compose.Carried of its own composition there; the node's own carries it wherever it runs there), so what the others
 // read of it (the machine ports its containers publish, the routes reaching it) is what runs, and none of its own
-// composition is in out: the node keeps what it last applied.
-//
-// **A hold never spreads** (issue 1126, issue 1960: de-spiegel's hold for an unset value held mailu, which held
-// route-proxy, nftables and postgres on novox). No module is held because a module it reads from is held: a consumer,
-// a collector, the provider of what the held one contributes to and the filter where it listens each compose with what
-// the held module last offered. That offer (what it contributes, contributes many, listens on) is its manifest at the
-// build it runs where one is known (ran: a composition of its own running at another build than it is composed at),
-// else the manifest it is composed from. Only the part of the offer that cannot compose is left out, by provision
-// (culprit): de-spiegel's routes, its names unset, leave route-proxy without them while mailu keeps its smtp account,
-// and the hold says so.
-func composeEach(in compose.Input, node string, fps map[string]string, applied bool, running []delivery.Composed, failed map[string]string,
-	ran func(module string) (catalogue.Manifest, bool)) (out map[string]delivery.Composed, skipped, stood []string, err error) {
+// composition is in out: the node keeps what it last applied. **What depends on how it is held is held too:** a module
+// whose composition differs when the held ones are composed as their stubs instead is held with them, and a node's own
+// composition that differs (but for the held modules' own resources) refuses the node. And since a held module is
+// composed from its new manifest, which may not be the build's that runs, what reads that manifest is held with it
+// (dependents): the providers of what it contributes to (the proxy its routes), and, when it listens, the filter.
+func composeEach(in compose.Input, node string, fps map[string]string, applied bool, running []delivery.Composed, failed map[string]string) (out map[string]delivery.Composed, skipped, stood []string, err error) {
 	mode := compose.Foreseeing
 	if applied {
 		mode = compose.Reading
@@ -298,46 +328,43 @@ func composeEach(in compose.Input, node string, fps map[string]string, applied b
 			runs[m] = &running[i]
 		}
 	}
-	src := map[string]catalogue.Manifest{} // each held module's manifest before it was held, offering what it last offered
-	left := map[string]map[string]bool{}   // by held module, what of its offer is left out (leaveOut)
-	hold := func(m, why, leave string) {
+	src := map[string]catalogue.Manifest{} // each held module's manifest before it was held
+	bareOf := map[string]bool{}
+	var hold func(m, why string, bare bool)
+	hold = func(m, why string, bare bool) {
 		if _, done := failed[m]; !done {
-			failed[m] = why // a held module tried again keeps the words it was first held for
+			failed[m] = why // a held module tried bare keeps the words it was first held for
 		}
+		first := false
 		if _, ok := src[m]; !ok {
 			man, ok := manifestOn(in, node, m)
 			if !ok {
 				return
 			}
-			if ran != nil {
-				if was, ok := ran(m); ok {
-					man.Contributes, man.ContributesMany, man.Listens = was.Contributes, was.ContributesMany, was.Listens
-				}
-			}
-			src[m] = man
+			src[m], first = man, true
 		}
-		if leave != "" {
-			if left[m] == nil {
-				left[m] = map[string]bool{}
-			}
-			left[m][leave] = true
-			if leave != leaveAll {
-				failed[m] += "; composed without what it contributes to " + leave + ", which does not compose"
-			}
+		bareOf[m] = bareOf[m] || bare
+		in = heldAs(in, node, m, src[m], bareOf[m], runs[m])
+		if !first {
+			return
+		}
+		// What the others read of its manifest (what it contributes, what it listens on) is its new manifest's, not
+		// necessarily the build's that runs: what reads it is held with it (review of the apply, round 2).
+		for _, r := range dependents(in, node, src[m], failed) {
+			hold(r, heldBehind(m), false)
 		}
-		in = heldAs(in, node, m, src[m], left[m], runs[m])
 	}
 	for _, m := range sortedKeys(failed) {
-		hold(m, failed[m], "")
+		hold(m, failed[m], false)
 	}
 	for {
 		out, skipped, stood, err = compose.CompositionsIn(in, node, fps, mode)
 		if err != nil {
-			module, leave := culprit(in, node, fps, mode, failed, err)
+			module, bare := culprit(in, node, fps, mode, failed, err)
 			if module == "" {
 				return nil, nil, nil, err
 			}
-			hold(module, err.Error(), leave)
+			hold(module, err.Error(), bare)
 			continue
 		}
 		again := false
@@ -357,7 +384,7 @@ func composeEach(in compose.Input, node string, fps map[string]string, applied b
 			}
 			for _, m := range sortedKeys(of) {
 				if _, done := failed[m]; !done {
-					hold(m, "stands in for "+strings.Join(of[m], ", "), "")
+					hold(m, "stands in for "+strings.Join(of[m], ", "), false)
 					again = true
 				}
 			}
@@ -365,6 +392,17 @@ func composeEach(in compose.Input, node string, fps map[string]string, applied b
 				return nil, nil, nil, fmt.Errorf("%w on %s: %s", compose.ErrStoodIn, node, strings.Join(nodes, ", "))
 			}
 		}
+		if !again && len(failed) > 0 {
+			dependent, own := dependsOnHeld(in, node, fps, mode, out, src, bareOf, failed)
+			if own {
+				return nil, nil, nil, fmt.Errorf("frombus: %s's own composition depends on how %s, held, is composed, and is not applied",
+					node, strings.Join(sortedKeys(failed), ", "))
+			}
+			for _, m := range dependent {
+				hold(m, "what it composes of "+strings.Join(sortedKeys(failed), ", ")+", held, is not what runs of them", false)
+				again = true
+			}
+		}
 		if !again {
 			break
 		}
@@ -373,9 +411,117 @@ func composeEach(in compose.Input, node string, fps map[string]string, applied b
 	return out, skipped, stood, nil
 }
 
-// leaveAll leaves out the whole of a held module's offer and its own secrets (a bare stub); any other word leaves out
-// what it contributes to that provision alone.
-const leaveAll = "*"
+// dependsOnHeld composes in again with each held module as its stub rather than as what runs of it, and answers the
+// modules, not held, whose composition differs between the two (sorted), and own when the node's own composition does
+// but for the held modules' own resources. A composition of stubs that fails says nothing more: what runs composed.
+func dependsOnHeld(in compose.Input, node string, fps map[string]string, mode compose.Mode, asRuns map[string]delivery.Composed,
+	src map[string]catalogue.Manifest, bareOf map[string]bool, failed map[string]string) (dependent []string, own bool) {
+	stubs := in
+	for _, m := range sortedKeys(failed) {
+		if man, ok := src[m]; ok {
+			stubs = heldAs(stubs, node, m, man, bareOf[m], nil)
+		}
+	}
+	asStubs, _, _, err := compose.CompositionsIn(stubs, node, fps, mode)
+	if err != nil {
+		return nil, false
+	}
+	isHeld := func(m string) bool { _, ok := failed[m]; return ok }
+	keys := map[string]bool{}
+	for k := range asRuns {
+		keys[k] = true
+	}
+	for k := range asStubs {
+		keys[k] = true
+	}
+	for _, k := range sortedKeys(keys) {
+		a, inA := asRuns[k]
+		b, inB := asStubs[k]
+		m := a.Module
+		if !inA {
+			m = b.Module
+		}
+		if m != "" && isHeld(m) {
+			continue
+		}
+		if m == "" {
+			a, b = withoutHeld(a, isHeld), withoutHeld(b, isHeld)
+		}
+		da, errA := delivery.ComposedDigestOf(a)
+		db, errB := delivery.ComposedDigestOf(b)
+		if inA == inB && errA == nil && errB == nil && da == db {
+			continue
+		}
+		if m == "" {
+			own = true
+			continue
+		}
+		dependent = append(dependent, m)
+	}
+	return dependent, own
+}
+
+// withoutHeld is the node's own composition c without the resources of a held module (its id naming it) and without
+// its filled paths, for comparing the rest.
+func withoutHeld(c delivery.Composed, isHeld func(string) bool) delivery.Composed {
+	out := c
+	out.Filled = nil
+	out.Resources = nil
+	for _, raw := range c.Resources {
+		var head struct {
+			ID     string `json:"id"`
+			Module string `json:"module"`
+		}
+		_ = json.Unmarshal(raw, &head)
+		owner := head.Module
+		if owner == "" {
+			owner, _ = declaration.ModuleGuess(head.ID)
+		}
+		if owner != "" && isHeld(owner) {
+			continue
+		}
+		out.Resources = append(out.Resources, raw)
+	}
+	return out
+}
+
+// dependents is, of the modules placed on node and not held, those that read what man says to them: each that provides
+// what man contributes to (the proxy its routes), and, when man listens on a port, each that holds the filter (the
+// openings).
+func dependents(in compose.Input, node string, man catalogue.Manifest, failed map[string]string) []string {
+	to := map[string]bool{}
+	for p := range man.Contributes {
+		to[p] = true
+	}
+	for p := range man.ContributesMany {
+		to[p] = true
+	}
+	listens := len(man.Listens) > 0
+	if len(to) == 0 && !listens {
+		return nil
+	}
+	var out []string
+	for _, m := range assignedOn(in, node) {
+		if _, held := failed[m]; held || m == man.Module {
+			continue
+		}
+		pm, ok := manifestOn(in, node, m)
+		if !ok {
+			continue
+		}
+		if listens && pm.Filtering != nil {
+			out = append(out, m)
+			continue
+		}
+		for _, o := range pm.Provides {
+			if to[o.Name] {
+				out = append(out, m)
+				break
+			}
+		}
+	}
+	return out
+}
 
 // assignedOn is the modules placed on node, in placement order.
 func assignedOn(in compose.Input, node string) []string {
@@ -400,14 +546,18 @@ func manifestOn(in compose.Input, node, module string) (catalogue.Manifest, bool
 	return man, ok
 }
 
-// culprit is the module placed on node whose composition the error is of, and what of its offer to leave out: the
-// first, in placement order, whose stub (compose.Stub) makes the composition in mode succeed or fail otherwise (leave
-// ""); else the first whose stub without what it contributes to one provision does (leave that provision: de-spiegel's
-// routes, its names unset, and not its smtp account, issue 1960); else the first whose bare stub does (leaveAll: its
-// stub contributing nothing, its own secret never issued, issue 1126 seed-8). Empty when none does (the error is not
-// one module's). Modules already refused are passed over for their stub.
-func culprit(in compose.Input, node string, fps map[string]string, mode compose.Mode, failed map[string]string, err error) (string, string) {
-	assigned := assignedOn(in, node)
+// culprit is the module placed on node whose composition the error is of: the first, in placement order, whose stub
+// (compose.Stub) makes the composition in mode succeed or fail otherwise; empty when none does (the error is not one
+// module's). Modules already refused are passed over. A module whose stub still fails the same is tried bare (its stub
+// contributing nothing, bare true): a refusal of what it contributes is its own, which the stub keeps (issue 1126,
+// seed-8: de-spiegel's route names on novox, an unset required value, refused the whole node).
+func culprit(in compose.Input, node string, fps map[string]string, mode compose.Mode, failed map[string]string, err error) (string, bool) {
+	var assigned []string
+	for _, n := range in.Nodes {
+		if n.Name == node {
+			assigned = n.Assigned
+		}
+	}
 	// Only the modules the error names: the words of a module's refusal name it. Each try is a whole composition, so a
 	// refusal naming none is no module's, answered at once rather than after a composition per module (issue 1126: ace's
 	// answer took 7m46s).
@@ -417,97 +567,65 @@ func culprit(in compose.Input, node string, fps map[string]string, mode compose.
 			order = append(order, m)
 		}
 	}
-	changes := func(m, leave string) bool {
-		_, _, _, again := compose.CompositionsIn(stubbed(in, node, m, leave), node, fps, mode)
+	changes := func(m string, bare bool) bool {
+		_, _, _, again := compose.CompositionsIn(stubbed(in, node, m, bare), node, fps, mode)
 		return again == nil || again.Error() != err.Error()
 	}
 	for _, m := range order {
 		if _, done := failed[m]; done {
 			continue
 		}
-		if changes(m, "") {
-			return m, ""
+		if changes(m, false) {
+			return m, false
+		}
+	}
+	var kept map[string]catalogue.Manifest
+	for _, n := range in.Nodes {
+		if n.Name == node {
+			kept = n.Kept
 		}
 	}
 	for _, m := range order {
-		man, ok := manifestOn(in, node, m)
-		if !ok {
+		// One already held is tried bare too, once: held for its build, its stub may still refuse (its own secret
+		// never issued, issue 1126).
+		if _, done := failed[m]; done && isBare(kept[m]) {
 			continue
 		}
-		// One already held is tried again too: held for its build, its stub may still refuse (its own secret never
-		// issued, issue 1126). A provision named in the error is tried first, each at one more composition.
-		var to []string
-		for p := range man.Contributes {
-			to = append(to, p)
-		}
-		for p := range man.ContributesMany {
-			if _, both := man.Contributes[p]; !both {
-				to = append(to, p)
-			}
-		}
-		sort.SliceStable(to, func(i, j int) bool {
-			return strings.Contains(err.Error(), " "+to[i]) && !strings.Contains(err.Error(), " "+to[j])
-		})
-		for _, p := range to {
-			if changes(m, p) {
-				return m, p
-			}
-		}
-		if isBare(man) {
-			continue
-		}
-		if changes(m, leaveAll) {
-			return m, leaveAll
+		if changes(m, true) {
+			return m, true
 		}
 	}
-	return "", ""
+	return "", false
 }
 
-// isBare says a stub contributes nothing and declares no own secret (stubbed, leaveAll).
+// isBare says a stub contributes nothing and declares no own secret (stubbed, bare).
 func isBare(m catalogue.Manifest) bool {
 	return len(m.Contributes) == 0 && len(m.ContributesMany) == 0 && len(m.OwnSecrets) == 0
 }
 
 // stubbed is in with module held on node as its stub alone (heldAs, nothing of it running), from the manifest node
-// composes it from, leave left out of its offer: a culprit's try.
-func stubbed(in compose.Input, node, module, leave string) compose.Input {
+// composes it from: a culprit's try.
+func stubbed(in compose.Input, node, module string, bare bool) compose.Input {
 	man, ok := manifestOn(in, node, module)
 	if !ok {
 		return in
 	}
-	var left map[string]bool
-	if leave != "" {
-		left = map[string]bool{leave: true}
-	}
-	return heldAs(in, node, module, man, left, nil)
+	return heldAs(in, node, module, man, bare, nil)
 }
 
 // heldAs is in with module held on node (compose.Node.Held): composed from man as what runs of it (compose.Carried of
-// runs; its stub, compose.Stub, when runs is nil or holds nothing of it), as node's Kept; with what left names out of
-// its offer: a provision's contributions, or with leaveAll everything it contributes and its own secrets, none of a
-// held module's own composition being applied, so what it has not been issued (restic's repository on a node it never
-// ran on) is no refusal of the rest.
-func heldAs(in compose.Input, node, module string, man catalogue.Manifest, left map[string]bool, runs *delivery.Composed) compose.Input {
+// runs; its stub, compose.Stub, when runs is nil or holds nothing of it), as node's Kept; bare, contributing nothing to
+// what it requires and declaring no own secret: none of a held module's own composition is applied, so what it has not
+// been issued (restic's repository on a node it never ran on) is no refusal of the rest.
+func heldAs(in compose.Input, node, module string, man catalogue.Manifest, bare bool, runs *delivery.Composed) compose.Input {
 	out := in
 	out.Nodes = append([]compose.Node(nil), in.Nodes...)
 	for i := range out.Nodes {
 		if out.Nodes[i].Name != node {
 			continue
 		}
-		if left[leaveAll] {
+		if bare {
 			man.Contributes, man.ContributesMany, man.OwnSecrets = nil, nil, nil
-		} else if len(left) > 0 {
-			contributes := map[string]map[string]any{}
-			for p, v := range man.Contributes {
-				if !left[p] {
-					contributes[p] = v
-				}
-			}
-			many := maps.Clone(man.ContributesMany)
-			for p := range left {
-				delete(many, p)
-			}
-			man.Contributes, man.ContributesMany = contributes, many
 		}
 		kept := make(map[string]catalogue.Manifest, len(out.Nodes[i].Kept)+1)
 		for k, v := range out.Nodes[i].Kept {

go/compose/frombus/answer_rows_test.go

@@ -104,12 +104,12 @@ func answerNamesEveryRefusalAndLeavesAnOldBuildToTheNode(t *testing.T) {
 	if part.Verdict != delivery.CandidateRefused || len(part.Refusals) != 2 || len(part.Held) != 1 || part.Held[0].Module != "api" {
 		t.Errorf("held as today in part: %+v", part)
 	}
-	// No module is held behind one kept today (issue 1960): mailu's own refusal stays a refusal beside de-spiegel's hold.
+	// A module held only behind one kept today is kept as today too, saying behind which (novox's mailu behind de-spiegel).
 	if a := (delivery.CandidateAnswer{Refusals: []delivery.ModuleRefused{{Module: "de-spiegel", Why: "a value is unset"},
-		{Module: "mailu", Why: "no build"}}}); true {
+		{Module: "mailu", Why: heldBehind("de-spiegel")}, {Module: "proxy", Why: heldBehind("mailu")}, {Module: "web", Why: "no build"}}}); true {
 		heldAsToday(&a, map[string]string{"de-spiegel": "runs a build of the old form"})
-		if len(a.Refusals) != 1 || a.Refusals[0].Module != "mailu" || len(a.Held) != 1 {
-			t.Errorf("held as today spreads: %+v", a)
+		if len(a.Refusals) != 1 || a.Refusals[0].Module != "web" || len(a.Held) != 3 || a.Held[2].Today != "held behind mailu" {
+			t.Errorf("held behind a module kept today: %+v", a)
 		}
 	}
 
@@ -330,26 +330,23 @@ func answerNamesEveryRefusalAndLeavesAnOldBuildToTheNode(t *testing.T) {
 	// de-spiegel folded, and its manifest at the indexer's commit (e25e1beb, captured) asks four required config values
 	// for its route names that nothing sets. novox answered the whole candidate refused ("de-spiegel contributing
 	// praktijk to route says ${setting:praktijk-name} ...": its stub still contributed the route). Only de-spiegel is
-	// refused, in the config form's words; the rest is judged. Issue 1960, novox's chain on 2026-10-29: the hold spread
-	// to mailu (its smtp provider) and proxy (its route provider), and from them on. Neither is held now: proxy composes
-	// without de-spiegel's routes, which do not compose, and mailu with its smtp account, which does.
+	// refused, in the config form's words, and proxy, which receives its routes (what it would compose lacks them: review
+	// of the apply, round 1); the rest is judged.
 	spiegel, err := os.ReadFile("testdata/de-spiegel-e25e1beb.module.json")
 	if err != nil {
 		t.Fatal(err)
 	}
-	proxy := []byte(`{"module":"proxy","version":"1","capabilities":["systemd"],"provides":[{"name":"route","scope":"mesh"}],` +
+	proxy := []byte(`{"module":"proxy","version":"1","capabilities":["systemd"],"provides":[{"name":"route","scope":"mesh"},{"name":"smtp","scope":"mesh"}],` +
 		`"resources":[{"id":"service","type":"service","unit":"proxy.service","state":"running","boot":"enabled"}]}`)
-	mailu := []byte(`{"module":"mailu","version":"1","capabilities":["systemd"],"provides":[{"name":"smtp","scope":"mesh"}],` +
-		`"resources":[{"id":"service","type":"service","unit":"mailu.service","state":"running","boot":"enabled"}]}`)
-	b = mk("lemurs", overlay.Name, "mailu", "proxy", "de-spiegel")
-	for m, raw := range map[string][]byte{"de-spiegel": spiegel, "proxy": proxy, "mailu": mailu} {
+	b = mk("lemurs", overlay.Name, "proxy", "de-spiegel")
+	for m, raw := range map[string][]byte{"de-spiegel": spiegel, "proxy": proxy} {
 		b.manifests[delivery.ManifestDigest(raw)] = raw
 		b.modules[m] = delivery.Module{Manifest: delivery.ManifestDigest(raw)}
 	}
 	p = b.placements["n1"]
 	p.Decided.Endpoint = "n1.example:51820"
 	b.placements["n1"] = p
-	fps = map[string]string{"lemurs": fp("e"), "proxy": fp("f"), "mailu": fp("d")}
+	fps = map[string]string{"lemurs": fp("e"), "proxy": fp("f")}
 	a = Answer(ctx, b, Mesh{}, Scope{Node: "n1", Placements: given(b), InOwn: []string{"de-spiegel"}}, fps, nil, "p-h1", 3)
 	refused = nil
 	for _, r := range a.Refusals {
@@ -358,13 +355,11 @@ func answerNamesEveryRefusalAndLeavesAnOldBuildToTheNode(t *testing.T) {
 			t.Errorf("de-spiegel is refused in other words than its config form's: %s", r.Why)
 		}
 	}
-	if a.Refused != "" || !reflect.DeepEqual(refused, []string{"de-spiegel"}) {
-		t.Errorf("a module's own refusal: %+v, want de-spiegel refused alone, the node, mailu and proxy not", a)
+	if a.Refused != "" || !reflect.DeepEqual(refused, []string{"de-spiegel", "proxy"}) {
+		t.Errorf("a module's own refusal: %+v, want de-spiegel refused with proxy, which receives its routes, the node not", a)
 	}
-	for _, m := range []string{"lemurs", "mailu", "proxy"} {
-		if !slices.ContainsFunc(a.Added, func(x delivery.ModuleAdded) bool { return x.Module == m }) {
-			t.Errorf("%s, which composes, is not judged beside de-spiegel's refusal: %+v", m, a)
-		}
+	if !slices.ContainsFunc(a.Added, func(m delivery.ModuleAdded) bool { return m.Module == "lemurs" }) {
+		t.Errorf("lemurs, which composes, is not judged beside de-spiegel's refusal: %+v", a)
 	}
 
 	// (E) Issue 1126, the applying path (review of the seed): the composition novox applies follows the same rule. It
@@ -398,13 +393,16 @@ func answerNamesEveryRefusalAndLeavesAnOldBuildToTheNode(t *testing.T) {
 	if err != nil {
 		t.Fatalf("de-spiegel's own refusal refuses the node's whole composition: %v", err)
 	}
-	if len(held) != 1 || !strings.Contains(held["de-spiegel"], "${config:praktijk-name}") || !strings.Contains(held["de-spiegel"], "without what it contributes to route") {
-		t.Errorf("held %v, want de-spiegel alone, in its config form's words, composed without its routes", held)
+	if len(held) != 2 || !strings.Contains(held["de-spiegel"], "${config:praktijk-name}") || !strings.Contains(held["proxy"], "de-spiegel") {
+		t.Errorf("held %v, want de-spiegel in its config form's words, and proxy for its routes", held)
 	}
-	for _, m := range []string{"lemurs", "mailu", "proxy"} {
-		if key, _ := delivery.ComposedKey("n1", m, fps[m]); got[key].Module != m {
-			t.Errorf("%s is not composed beside de-spiegel's hold: %v", m, sortedKeys(got))
-		}
+	lemursKey, _ := delivery.ComposedKey("n1", "lemurs", fps["lemurs"])
+	proxyKey, _ := delivery.ComposedKey("n1", "proxy", fps["proxy"])
+	if _, ok := got[lemursKey]; !ok {
+		t.Errorf("lemurs, which composes, is not composed beside de-spiegel's refusal: %v", sortedKeys(got))
+	}
+	if _, ok := got[proxyKey]; ok {
+		t.Errorf("proxy is composed without the routes of held de-spiegel: %v", sortedKeys(got))
 	}
 	carries := func(c delivery.Composed, what string) {
 		t.Helper()
@@ -435,8 +433,8 @@ func answerNamesEveryRefusalAndLeavesAnOldBuildToTheNode(t *testing.T) {
 
 	// (G) A held module that runs a composition of its own (review of the apply, round 1, finding 2): what the others
 	// compose of it is what runs, never its stub's. site listens on 8080, placed at the machine's 20005, and its own
-	// secret was never issued here: held, the filter must not open 8080 and drop the 20005 that runs. The filter, which
-	// reads what site listens on, composes with it (issue 1960: a hold never spreads).
+	// secret was never issued here: held, the filter must not open 8080 and drop the 20005 that runs. A module whose
+	// composition depends on how site is held (here the filter) is held with it.
 	site := []byte(`{"module":"site","version":"1","capabilities":["container-runtime"],` +
 		`"listens":[{"port":8080,"from":"mesh","why":"the site"}],"own-secrets":{"key":"${dir:state}/key"},` +
 		`"resources":[{"id":"state","type":"directory","path":"/var/lib/site","mode":"0700"},` +
@@ -462,12 +460,8 @@ func answerNamesEveryRefusalAndLeavesAnOldBuildToTheNode(t *testing.T) {
 		json.RawMessage(`{"id":"site.state","module":"site","type":"directory","path":"/var/lib/site","mode":"0700"}`),
 		json.RawMessage(`{"id":"site.server","module":"site","type":"container","name":"site","image":"registry.example/site@sha256:` + strings.Repeat("c", 64) + `","ports":["10.77.0.1:20005:8080"]}`)}}
 	got, _, held, err = Compose(ctx, b, Mesh{}, Scope{Node: "n1", Running: []delivery.Composed{siteRuns}}, fps)
-	nftKey, _ := delivery.ComposedKey("n1", "nft", fps["nft"])
-	if err != nil || held["site"] == "" || held["nft"] != "" || got[nftKey].Module != "nft" {
-		t.Fatalf("site, its own secret never issued: %v, held %v; want site held alone, and the filter composed", err, held)
-	}
-	if rules, _ := json.Marshal(got[nftKey].Resources); !strings.Contains(string(rules), "dport 20005") {
-		t.Errorf("the filter drops held site's opening where it runs (20005): %s", rules)
+	if err != nil || held["site"] == "" || held["nft"] == "" {
+		t.Fatalf("site, its own secret never issued: %v, held %v; want site held, and the filter, which depends on it", err, held)
 	}
 	for key, c := range got {
 		for _, raw := range c.Resources {
@@ -476,56 +470,10 @@ func answerNamesEveryRefusalAndLeavesAnOldBuildToTheNode(t *testing.T) {
 			}
 		}
 	}
-	// (G2) Issue 1126, the spreading hold: a held module is no dependence of its neighbours. site, held, provides page, and
-	// app requires and binds it: app composes against what runs of site and is not held (novox's seed held every postgres
-	// consumer behind de-spiegel's hold, "what it composes of …, held, is not what runs of them").
-	provider := []byte(strings.Replace(string(site), `"listens":`, `"provides":[{"name":"page","scope":"node"}],"serves":{"page":{"port":8080}},"listens":`, 1))
-	app := []byte(`{"module":"app","version":"1","capabilities":["systemd"],"requires":["page"],"binds":{"page":"/etc/app/page.json"},` +
-		`"resources":[{"id":"service","type":"service","unit":"app.service","state":"running","boot":"enabled"}]}`)
-	b2 := mk("lemurs", overlay.Name, "site", "nft", "app")
-	for m, raw := range map[string][]byte{"site": provider, "nft": nft, "app": app} {
-		b2.manifests[delivery.ManifestDigest(raw)] = raw
-		b2.modules[m] = delivery.Module{Manifest: delivery.ManifestDigest(raw)}
-	}
-	p2 := b2.placements["n1"]
-	p2.Decided.Endpoint = "n1.example:51820"
-	for i := range p2.Modules {
-		if p2.Modules[i].Module == "site" {
-			p2.Modules[i].Ports = map[string]int{"8080": 20005}
-		}
-	}
-	b2.placements["n1"] = p2
-	b2.records["n1"] = rec
-	b2.held = true
-	fps["app"] = fp("9")
-	got, _, held, err = Compose(ctx, b2, Mesh{}, Scope{Node: "n1", Running: []delivery.Composed{siteRuns}}, fps)
-	appKey, _ := delivery.ComposedKey("n1", "app", fps["app"])
-	if _, composed := got[appKey]; err != nil || held["site"] == "" || held["app"] != "" || !composed {
-		t.Errorf("a consumer of held site: %v, held %v; want site held, and app composed against what runs of it", err, held)
-	}
-	if bound, _ := json.Marshal(got[appKey].Resources); !strings.Contains(string(bound), "20005") {
-		t.Errorf("app's binding does not reach held site where it runs (20005): %s", bound)
-	}
-	delete(fps, "app")
-	// A held module's offer is left out by provision, never whole when one part composes (issue 1960): de-spiegel's
-	// routes, its names unset, leave the proxy without them, and its smtp account stays with mailu.
-	withProxy := compose.Input{Catalogue: map[string]catalogue.Manifest{},
-		Nodes: []compose.Node{{Name: "n1", Assigned: []string{"feeder"}}}}
-	feeder := catalogue.Manifest{Module: "feeder", Contributes: map[string]map[string]any{"route": {"name": "x"}, "smtp": {"account": "feeder"}},
-		OwnSecrets: catalogue.OwnSecrets{"key": {Path: "/k"}}}
-	for _, row := range []struct {
-		left             map[string]bool
-		route, smtp, own bool
-	}{{nil, true, true, true}, {map[string]bool{"route": true}, false, true, true}, {map[string]bool{leaveAll: true}, false, false, false}} {
-		k := heldAs(withProxy, "n1", "feeder", feeder, row.left, nil).Nodes[0].Kept["feeder"]
-		if _, r := k.Contributes["route"]; r != row.route || (k.Contributes["smtp"] != nil) != row.smtp || (len(k.OwnSecrets) > 0) != row.own {
-			t.Errorf("held leaving out %v offers %+v, own secrets %v", row.left, k.Contributes, k.OwnSecrets)
-		}
-	}
 	// (H) Review of the apply, round 2: a held module is composed from its new manifest, so what the others read of its
 	// manifest (its listens, what it contributes) may not be what runs. site's new manifest moves it to 9090 while the
-	// build that runs (7) listens on 8080. The filter composes with what site last offered, its manifest at the build
-	// that runs (issue 1960: a hold never spreads), so it opens 8080 and nothing applied opens 9090.
+	// build that runs listens on 8080: the filter, the holder of what site listens on, is held with it, and nothing
+	// applied opens 9090.
 	moved := []byte(strings.Replace(string(site), `"port":8080`, `"port":9090`, 1))
 	b.manifests[delivery.ManifestDigest(moved)] = moved
 	b.modules["site"] = delivery.Module{Manifest: delivery.ManifestDigest(moved)}
@@ -534,15 +482,9 @@ func answerNamesEveryRefusalAndLeavesAnOldBuildToTheNode(t *testing.T) {
 	}
 	b.placements["n1"] = p
 	siteRuns.Resources[1] = json.RawMessage(`{"id":"site.server","module":"site","type":"container","name":"site","image":"registry.example/site@sha256:` + strings.Repeat("c", 64) + `","ports":["8080"]}`)
-	siteRuns.FP = fp("7")
-	b.manifests[delivery.ManifestDigest(site)] = site
-	b.builds["site "+fp("7")] = &delivery.BuilderBuild{State: delivery.BuildDone, Manifest: delivery.ManifestDigest(site)}
 	got, _, held, err = Compose(ctx, b, Mesh{}, Scope{Node: "n1", Running: []delivery.Composed{siteRuns}}, fps)
-	if err != nil || held["site"] == "" || held["nft"] != "" {
-		t.Errorf("site moved to 9090 in its new manifest: %v, held %v; want site held alone", err, held)
-	}
-	if rules, _ := json.Marshal(got[nftKey].Resources); !strings.Contains(string(rules), "dport 8080") {
-		t.Errorf("the filter drops what held site last offered (8080): %s", rules)
+	if err != nil || held["site"] == "" || held["nft"] == "" {
+		t.Errorf("site moved to 9090 in its new manifest: %v, held %v; want site held, and the filter with it", err, held)
 	}
 	for key, c := range got {
 		for _, raw := range c.Resources {

go/compose/frombus/frombus.go

@@ -240,7 +240,12 @@ func input(ctx context.Context, r Reader, mesh Mesh, s Scope, refuse func(module
 			in.Authority = delivery.AuthorityBundle(in.Authority, vault)
 		}
 	}
-	parse := parser(mesh)
+	parse := func(raw []byte) (catalogue.Manifest, error) {
+		if mesh.Predefined != nil {
+			return catalogue.ParseManifestWith(raw, mesh.Predefined)
+		}
+		return catalogue.ParseManifestForInputs(raw)
+	}
 	read := func(module, digest string) (catalogue.Manifest, error) {
 		raw, err := r.Manifest(ctx, digest)
 		if err != nil {
@@ -308,8 +313,6 @@ func input(ctx context.Context, r Reader, mesh Mesh, s Scope, refuse func(module
 			}
 		}
 		if node == s.Node {
-			// What its runtime serves as it runs: what a module composed as what runs of it contributes there (issue 1126).
-			n.RunsTools = compose.ToolsRunning(s.Running)
 			for _, module := range s.InOwn {
 				if n.InOwn == nil {
 					n.InOwn = map[string]bool{}
@@ -422,47 +425,10 @@ func Compose(ctx context.Context, r Reader, mesh Mesh, s Scope, fps map[string]s
 			return nil, nil, held, fmt.Errorf("frombus: the credentials of %s: %w", s.Node, err)
 		}
 	}
-	out, skipped, _, err = composeEach(in, s.Node, fps, true, s.Running, held, ranOf(ctx, r, mesh, s.Running, fps))
+	out, skipped, _, err = composeEach(in, s.Node, fps, true, s.Running, held)
 	return out, skipped, held, err
 }
 
-// parser reads a manifest as the indexer does, against the mesh's predefined keys when given.
-func parser(mesh Mesh) func([]byte) (catalogue.Manifest, error) {
-	return func(raw []byte) (catalogue.Manifest, error) {
-		if mesh.Predefined != nil {
-			return catalogue.ParseManifestWith(raw, mesh.Predefined)
-		}
-		return catalogue.ParseManifestForInputs(raw)
-	}
-}
-
-// ranOf is what a module last offered the others, read when it is held (composeEach, issue 1960): its manifest at the
-// build its own composition runs at (running), where that is another build than the one it is composed at (fps) and
-// the builder holds it done. False where nothing is known of it (it runs no composition of its own, it runs the build
-// it is composed at, or its build is unread): the manifest it is composed from is its offer then. Only what it says to
-// others is taken of it, which needs no take-in of its artifacts.
-func ranOf(ctx context.Context, r Reader, mesh Mesh, running []delivery.Composed, fps map[string]string) func(string) (catalogue.Manifest, bool) {
-	parse := parser(mesh)
-	return func(module string) (catalogue.Manifest, bool) {
-		for _, c := range running {
-			if c.Module != module || c.FP == "" || c.FP == fps[module] {
-				continue
-			}
-			b, err := r.Build(ctx, module, c.FP)
-			if err != nil || b == nil || b.State != delivery.BuildDone || b.Manifest == "" {
-				return catalogue.Manifest{}, false
-			}
-			raw, err := r.Manifest(ctx, b.Manifest)
-			if err != nil {
-				return catalogue.Manifest{}, false
-			}
-			man, err := parse(raw)
-			return man, err == nil
-		}
-		return catalogue.Manifest{}, false
-	}
-}
-
 // fromBuilds puts in the built manifest of each module placed on the composing node, at the trunk's FP2, and of each
 // module it keeps at another build (Scope.KeptAt, into its node's Kept), read from the builder's done key and resolved
 // by the one take-in rule (takein.Manifest), a templates archive read in the artifact store as the node reaches it

go/compose/frombus/frombus_test.go

@@ -45,8 +45,6 @@ type bus struct {
 	served     map[string]map[string]any
 	servedRead []string
 	buildsRead []string
-	// held answers every credential asked as held, sealed to the consumer.
-	held bool
 }
 
 func (b *bus) Build(_ context.Context, module, fp string) (*delivery.BuilderBuild, error) {
@@ -91,7 +89,7 @@ func (b *bus) OwnSecrets(context.Context, string) ([]compose.OwnSecretRow, error
 	return b.own, b.ownErr
 }
 
-func (b *bus) Credentials(_ context.Context, node string, asConsumer, asProvider []compose.CredentialKey) ([]compose.Credential, []compose.Issued, error) {
+func (b *bus) Credentials(_ context.Context, node string, asConsumer, _ []compose.CredentialKey) ([]compose.Credential, []compose.Issued, error) {
 	b.asked = append(b.asked, asConsumer...)
 	for _, k := range asConsumer {
 		placed := false
@@ -102,17 +100,7 @@ func (b *bus) Credentials(_ context.Context, node string, asConsumer, asProvider
 			return nil, nil, fmt.Errorf("%s is not on %s: neither assigned there nor required by a module there", k.ConsumerModule, node)
 		}
 	}
-	var out []compose.Credential
-	var issued []compose.Issued
-	for _, k := range append(append([]compose.CredentialKey{}, asConsumer...), asProvider...) {
-		if b.held {
-			out = append(out, compose.Credential{Provision: k.Provision, Consumer: k.Consumer, ConsumerModule: k.ConsumerModule,
-				Provider: k.Provider, Local: k.Local, State: compose.CredentialHeld, Sealed: `"box"`})
-			issued = append(issued, compose.Issued{Provision: k.Provision, Consumer: k.Consumer, ConsumerModule: k.ConsumerModule,
-				Provider: k.Provider, Local: k.Local, ForProvider: `"box"`})
-		}
-	}
-	return out, issued, nil
+	return nil, nil, nil
 }
 
 func (b *bus) Values(_ context.Context, node, module string) (map[string]any, error) {

go/compose/input.go

@@ -210,12 +210,6 @@ type Node struct {
 	// (RunsOwn), folded or leaving the fold, is carried there as it runs, whatever its manifest names, so the node's own
 	// never drops it.
 	Held map[string]bool
-	// RunsTools is, by module, the tools bundles the node's runtime serves of it as it runs (ToolsRunning of what the
-	// node runs); nil when not known. A module composed as what runs of it (its Stub or Carried: held, or folded at a
-	// build of the old form) contributes these to the runtime, never its manifest's: a manifest no build resolved has no
-	// bundles, and a held module's new build's bundles are not delivered (issue 1126, 2026-10-29: shanks's runtime lost
-	// the folded systemd-resolved, novox's the folded nats).
-	RunsTools map[string][]catalogue.Bundle
 }
 
 // Place is where a node is, as its placement says (inv.Overlay).

go/delivery/judge.go

@@ -3,7 +3,6 @@ package delivery
 import (
 	"bytes"
 	"encoding/json"
-	"fmt"
 	"path"
 	"sort"
 	"strings"
@@ -85,6 +84,9 @@ func judged(from, to Composed) (Judgement, string) {
 	if ids := changedOf(before, after, func(kind string) bool { return kind == string(declaration.TypeContainer) }); len(ids) > 0 {
 		return JudgedRecreates, "it recreates " + strings.Join(ids, ", ")
 	}
+	if from.Data != to.Data {
+		return JudgedMovesData, "its data declaration changes"
+	}
 	places := dataPlaces(before, after)
 	held := func(kind string) bool {
 		return kind == string(declaration.TypeDirectory) || kind == string(declaration.TypeFile)
@@ -102,20 +104,9 @@ func judged(from, to Composed) (Judgement, string) {
 	if to.Data || from.Data {
 		moved = append(moved, changedOf(before, after, func(kind string) bool { return kind == string(declaration.TypeProcess) })...)
 	}
-	// A data flag that differs is no move of data by itself: data moves only when a data item does (issue 1126, 2026-10-29:
-	// a running composition read back from the kept declaration carries no flag, and mongodb's toolchain move asked a yes for
-	// moving its data). It is said loudly in the words, and never hides an item that moved.
 	if len(moved) > 0 {
 		sort.Strings(moved)
-		words := "it changes where its data is kept: " + strings.Join(moved, ", ")
-		if from.Data != to.Data {
-			words += fmt.Sprintf("; its data flag differs too (running %v, composed %v)", from.Data, to.Data)
-		}
-		return JudgedMovesData, words
-	}
-	if from.Data != to.Data {
-		return JudgedNeither, fmt.Sprintf("it recreates no container and moves no data; WARNING: its data flag differs "+
-			"(running %v, composed %v) while no data item does, so one side's flag is wrong", from.Data, to.Data)
+		return JudgedMovesData, "it changes where its data is kept: " + strings.Join(moved, ", ")
 	}
 	return JudgedNeither, "it recreates no container and moves no data"
 }

go/delivery/judge_test.go

@@ -48,8 +48,7 @@ func TestJudgeMove(t *testing.T) {
 		{"a container gone", mail('a', true, container, spool), mail('b', true, spool), JudgedRecreates, false},
 		{"its spool moved", mail('a', true, container, spool), mail('b', true, container, spoolMoved), JudgedMovesData, false},
 		{"a file in its spool", mail('a', true, container, spool, config), mail('b', true, container, spool, config2), JudgedMovesData, false},
-		{"its data flag alone", mail('a', false, container, spool), mail('b', true, container, spool), JudgedNeither, false},
-		{"its data flag and its spool", mail('a', false, container, spool), mail('b', true, container, spoolMoved), JudgedMovesData, false},
+		{"its data declaration", mail('a', false, container, spool), mail('b', true, container, spool), JudgedMovesData, false},
 		{"a process of a module with data", mail('a', true, spool, process), mail('b', true, spool, process2), JudgedMovesData, false},
 		{"a process of a module without", mail('a', false, process), mail('b', false, process2), JudgedNeither, false},
 		{"its tools only", mail('a', true, container, spool, tools), mail('b', true, container, spool, tools2), JudgedNeither, false},
@@ -62,9 +61,6 @@ func TestJudgeMove(t *testing.T) {
 		if got.Judgement != c.want || got.UserListOnly != c.userList || got.Words == "" {
 			t.Errorf("%s: %+v, want %s (user list only %v)", c.name, got, c.want, c.userList)
 		}
-		if strings.Contains(c.name, "data flag alone") && !strings.Contains(got.Words, "WARNING: its data flag differs") {
-			t.Errorf("%s: the flag's difference is not said: %q", c.name, got.Words)
-		}
 	}
 	if got := JudgeMove(nil, Composed{Node: "ace"}); got.Judgement != JudgedNeither {
 		t.Errorf("the node's own composition: %+v", got)