Feature 57 (config and provisioning): release mesh-controller, the reviewed release branch merged with main, on top of main

internal/builder/builder.go

@@ -108,6 +108,17 @@ type Result struct {
 	// recipe and the package it compiles; for any other, nothing is said and the whole of what the build
 	// sees stays its source, as before.
 	Sources []BuildSource
+
+	// Predefined is the list of predefined keys at the root of the repository at the commit built (novox/hq ADR
+	// 0348 §7), which the manifest was judged against; nil for a repository that holds none.
+	Predefined *Predefined
+}
+
+// Predefined is the list of predefined keys a build read: its text, canonical (catalogue.PredefinedList), and
+// the generation of the commit built — how many commits it stands on, which orders two builds of one trunk.
+type Predefined struct {
+	Keys       []byte
+	Generation int
 }
 
 // BuildSource is the build source a build read in one repository (novox/hq ADR 0267).
@@ -265,14 +276,38 @@ func build(ctx context.Context, run Runner, publish Publisher,
 			"%s has no %s at %s, so there is nothing saying what it is: %w",
 			repository, ManifestName, describe(path), err)
 	}
-	manifest, err := catalogue.ParseManifest(raw)
+	// **The list of predefined keys at the commit built** (novox/hq ADR 0348 §7): predefined.json at the
+	// repository's root, read strictly; a list that is wrong fails the build, and the manifest is judged against
+	// the list of its own tree, never against one the mesh published from another commit.
+	predefined, err := catalogue.ReadPredefined(tree)
+	if err != nil {
+		say("predefined", "INVALID: %v", err)
+		return Result{}, err
+	}
+	manifest, err := catalogue.ParseManifestWith(raw, predefined)
 	if err != nil {
 		say("manifest", "INVALID: %v", err)
 		return Result{}, err
 	}
+	var listed *Predefined
+	if predefined != nil {
+		text, err := predefined.Canonical()
+		if err != nil {
+			return Result{}, err
+		}
+		listed = &Predefined{Keys: text, Generation: generationOf(ctx, run, tree, commit)}
+		say("predefined", "%d key(s) at %s, generation %d", len(predefined), short(commit), listed.Generation)
+	}
 	// What is judged only where a definition is written (novox/hq ADR 0326 §3, issue 574): a build is
 	// where a changed definition is first read, so it is refused here before anything is made of it.
-	if problems := catalogue.WrittenSettingsProblems(manifest); len(problems) > 0 {
+	// Judged with each template's text in its file, as written in the tree (novox/hq ADR 0349 §2): a template the
+	// module's directory lacks is refused here, before anything is built.
+	judged, err := catalogue.WithTemplatesFrom(manifest, within)
+	if err != nil {
+		say("manifest", "INVALID: %v", err)
+		return Result{}, err
+	}
+	if problems := catalogue.WrittenSettingsProblems(judged); len(problems) > 0 {
 		err := fmt.Errorf("%s", strings.Join(problems, "; "))
 		say("manifest", "INVALID: %v", err)
 		return Result{}, err
@@ -288,6 +323,11 @@ func build(ctx context.Context, run Runner, publish Publisher,
 	if src.tree, err = gitTree(ctx, run, tree, path); err != nil {
 		src.notPinned("its tree could not be named: " + err.Error())
 	}
+	// A module falling back to a predefined key was judged against the list, so a change to the list is a change
+	// to it: the planner rebuilds it, and its build publishes the list (ADR 0348 §7).
+	if predefined != nil && manifest.NamesPredefined() {
+		src.rootHas(catalogue.PredefinedFile)
+	}
 
 	// A build-time credential, written into the build context as .npmrc, but ONLY for a module that
 	// asks for it: a `package` artifact (which publishes), or an image whose Dockerfile COPYs .npmrc.
@@ -419,6 +459,11 @@ func build(ctx context.Context, run Runner, publish Publisher,
 		}
 	}
 
+	// Each template's text, read back from the archive the build made or took (novox/hq ADR 0349 §2).
+	if built, err = withTemplateTexts(manifest, within, built); err != nil {
+		say("templates", "FAILED: %v", err)
+		return Result{}, err
+	}
 	resolved, err := manifest.Resolve(built)
 	if err != nil {
 		say("resolve", "FAILED: %v", err)
@@ -448,7 +493,23 @@ func build(ctx context.Context, run Runner, publish Publisher,
 	return Result{Manifest: resolved, Commit: commit, Built: built,
 		Against: against(within, manifest, stoodOn), Read: readBy(manifest), Source: fingerprint,
 		Trunk: trunk, OnTrunk: onTrunk, Branches: branches, Sources: sources,
-		ReuseKey: key.Key, ReuseParts: key.Parts, NoKey: key.Why, Reused: reused, Why: builtWhy}, nil
+		ReuseKey: key.Key, ReuseParts: key.Parts, NoKey: key.Why, Reused: reused, Why: builtWhy,
+		Predefined: listed}, nil
+}
+
+// generationOf is how many commits the commit built stands on, itself included: of two commits on one trunk the
+// later has more, so the controller keeps the list of the newer one whatever order it hears them in (ADR 0348
+// §7). 0 when git could not say.
+func generationOf(ctx context.Context, run Runner, tree, commit string) int {
+	out, err := run(ctx, tree, "git", "rev-list", "--count", commit)
+	if err != nil {
+		return 0
+	}
+	n, err := strconv.Atoi(strings.TrimSpace(out))
+	if err != nil || n < 0 {
+		return 0
+	}
+	return n
 }
 
 // takeACheckBuild is the walk's look for a check build of its key (novox/hq ADR 0350 §2, §3): the key taken by

internal/builder/builder_test.go

@@ -83,6 +83,8 @@ func (r *recorded) run(_ context.Context, dir, name string, args ...string) (str
 		return r.tree + "\n", nil
 	case name == "git" && len(args) > 0 && args[0] == "rev-parse":
 		return "c0ffeec0ffeec0ffeec0ffeec0ffeec0ffeec0ff\n", nil
+	case name == "git" && len(args) > 1 && args[0] == "rev-list" && args[1] == "--count":
+		return "42\n", nil
 	}
 	return "", nil
 }

internal/builder/predefined_test.go

@@ -0,0 +1,106 @@
+package builder
+
+import (
+	"context"
+	"slices"
+	"strings"
+	"testing"
+
+	"github.com/novox/mesh-controller/internal/catalogue"
+)
+
+// A build reads the list of predefined keys at the root of the repository at the commit it builds (novox/hq ADR
+// 0348 §7, design 57 package K2, issue 661): it refuses a list that is wrong, judges the manifest against it, and
+// carries it with the commit's generation for the controller to publish.
+
+const theFirstKeys = `{
+  "font-size": {"type": "number", "description": "the size text is shown in, in points", "minimum": 6, "maximum": 72},
+  "agent-managed-settings": {"type": "object", "description": "the managed settings of every agent session, a JSON object", "trusted": true}
+}`
+
+// fallingBack is a module of the catalogue whose font size falls back to the predefined key named.
+func fallingBack(key, kind string) string {
+	def := "10"
+	if kind == "string" {
+		def = `"10"`
+	}
+	return `{"module":"dunst","version":"1",
+  "build":{"artifacts":[{"name":"look","kind":"archive","from":"files"}]},
+  "config":{"font-size":{"type":"` + kind + `","description":"the notification's font size, in points",
+    "default":` + def + `,"predefined":"` + key + `"}},
+  "resources":[
+    {"id":"theme","type":"archive","path":"/opt/dunst","artifact":"look"},
+    {"id":"rc","type":"file","path":"/etc/xdg/dunst/dunstrc","content":"font = Inter ${config:font-size}\n"}]}`
+}
+
+func buildInTheCatalogue(t *testing.T, manifest string, list *string) (Result, error) {
+	t.Helper()
+	r := &recorded{contents: map[string]string{"modules/dunst/" + ManifestName: manifest,
+		"modules/dunst/files/theme.conf": "dark", "README.md": "the catalogue"}}
+	if list != nil {
+		r.contents[catalogue.PredefinedFile] = *list
+	}
+	return Build(context.Background(), onTrunk{recorded: r}.run, r, "https://forge.invalid/mesh-catalog.git",
+		"modules/dunst", "", t.TempDir(), nil, Npmrc{}, GitCredential{}, nil)
+}
+
+func TestABuildNamingAPredefinedKeyIsJudgedAgainstItsTreesListAndCarriesIt(t *testing.T) {
+	list := theFirstKeys
+	got, err := buildInTheCatalogue(t, fallingBack("font-size", "number"), &list)
+	if err != nil {
+		t.Fatalf("a module falling back to font-size did not build: %v", err)
+	}
+	if got.Predefined == nil || got.Predefined.Generation != 42 {
+		t.Fatalf("the list was not carried with its generation: %+v", got.Predefined)
+	}
+	carried, err := catalogue.ParsePredefined(got.Predefined.Keys)
+	if err != nil || len(carried) != 2 || carried["font-size"].Type != catalogue.ConfigNumber {
+		t.Fatalf("the list carried is %s (%v)", got.Predefined.Keys, err)
+	}
+	// A change to the list is a change to the module that was judged against it.
+	if len(got.Sources) == 0 || !slices.Contains(got.Sources[0].Paths, catalogue.PredefinedFile) {
+		t.Fatalf("its build source leaves the list out: %+v", got.Sources)
+	}
+
+	for _, c := range []struct{ manifest, says string }{
+		{fallingBack("font-scale", "number"), `"font-scale", which is not on the list`},
+		{fallingBack("font-size", "string"), "which is a number, and this value is a string"},
+	} {
+		if _, err := buildInTheCatalogue(t, c.manifest, &list); err == nil || !strings.Contains(err.Error(), c.says) {
+			t.Errorf("wanted the build refused saying %q, got %v", c.says, err)
+		}
+	}
+}
+
+func TestABuildRefusesAWrongList(t *testing.T) {
+	wrong := `{"font-size": {"type": "number", "description": "points", "unit": "pt"}}`
+	if _, err := buildInTheCatalogue(t, fallingBack("font-size", "number"), &wrong); err == nil ||
+		!strings.Contains(err.Error(), `unknown field "unit"`) {
+		t.Fatalf("a wrong list was built with: %v", err)
+	}
+}
+
+// A repository without the list builds as before, carrying none; a value naming a key there is refused.
+func TestABuildWithoutAListCarriesNone(t *testing.T) {
+	plain := strings.Replace(fallingBack("font-size", "number"), `,"predefined":"font-size"`, "", 1)
+	got, err := buildInTheCatalogue(t, plain, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got.Predefined != nil {
+		t.Fatalf("a list was carried from a tree holding none: %+v", got.Predefined)
+	}
+	if slices.Contains(got.Sources[0].Paths, catalogue.PredefinedFile) {
+		t.Fatalf("the build source names a list: %+v", got.Sources)
+	}
+	if _, err := buildInTheCatalogue(t, fallingBack("font-size", "number"), nil); err == nil ||
+		!strings.Contains(err.Error(), "is not present") {
+		t.Fatalf("a key named where no list is: %v", err)
+	}
+	// A list present and a module naming no key: carried, and not the module's build source.
+	list := theFirstKeys
+	got, err = buildInTheCatalogue(t, plain, &list)
+	if err != nil || got.Predefined == nil || slices.Contains(got.Sources[0].Paths, catalogue.PredefinedFile) {
+		t.Fatalf("a module naming no key: %+v %+v %v", got.Predefined, got.Sources, err)
+	}
+}

internal/builder/reuse_test.go

@@ -74,8 +74,14 @@ const reusedModule = `{"module":"meshboard","version":"1",
 // aModuleAt is a repository holding the module under mod/, whose directory git names as tree, on its trunk.
 func aModuleAt(t *testing.T, tree string) (*recorded, Runner, string) {
 	t.Helper()
-	r := &recorded{tree: tree, contents: map[string]string{"mod/" + ManifestName: reusedModule,
-		"mod/Dockerfile": "FROM scratch", "mod/files/theme.conf": "dark"}}
+	return aModuleWith(t, tree, map[string]string{"mod/" + ManifestName: reusedModule,
+		"mod/Dockerfile": "FROM scratch", "mod/files/theme.conf": "dark"})
+}
+
+// aModuleWith is aModuleAt with the repository's files given.
+func aModuleWith(t *testing.T, tree string, contents map[string]string) (*recorded, Runner, string) {
+	t.Helper()
+	r := &recorded{tree: tree, contents: contents}
 	run := func(ctx context.Context, dir, name string, args ...string) (string, error) {
 		if name == "git" && len(args) > 0 && args[0] == "symbolic-ref" {
 			r.ran = append(r.ran, name+" "+strings.Join(args, " "))
@@ -101,6 +107,12 @@ var aPull = PullRef{Owner: "novox", Repo: "meshboard", Number: 7}
 func aCheckBuilt(t *testing.T, scratch *aScratch, tree string) CheckBuilt {
 	t.Helper()
 	r, run, workspace := aModuleAt(t, tree)
+	return aCheckBuiltBy(t, scratch, r, run, workspace)
+}
+
+// aCheckBuiltBy is aCheckBuilt of the repository given.
+func aCheckBuiltBy(t *testing.T, scratch *aScratch, r *recorded, run Runner, workspace string) CheckBuilt {
+	t.Helper()
 	spec := CheckSpec{ID: "build-1", Owner: aPull.Owner, Repo: aPull.Repo, Number: aPull.Number,
 		Builds: []CheckBuildSpec{{Module: "meshboard", Repository: "https://forge.invalid/meshboard.git", Path: "mod",
 			Ref: "main"}}}

internal/builder/source.go

@@ -58,6 +58,9 @@ type sourceInputs struct {
 	// whole when an artifact's is not known (novox/hq ADR 0267).
 	own      map[string]bool
 	ownIsAll bool
+	// root is the module's build source in its own repository outside its directory, relative to the
+	// repository's root: the list of predefined keys a manifest naming one was judged against (ADR 0348 §7).
+	root map[string]bool
 	// read is, per context (repository and ref), the build source read there; nil for one read whole.
 	read   map[string]map[string]bool
 	readAs map[string]catalogue.ArtifactContext
@@ -86,6 +89,9 @@ func (s *sourceInputs) copy() *sourceInputs {
 	for k, v := range s.own {
 		c.own[k] = v
 	}
+	for k, v := range s.root {
+		c.root[k] = v
+	}
 	for k, v := range s.read {
 		if v == nil {
 			c.read[k] = nil
@@ -112,7 +118,7 @@ func (s *sourceInputs) contextOffHead() {
 
 func newSourceInputs(module string) *sourceInputs {
 	return &sourceInputs{module: module, contexts: map[string]string{}, toolchains: map[string]string{},
-		own: map[string]bool{}, read: map[string]map[string]bool{}, readAs: map[string]catalogue.ArtifactContext{},
+		own: map[string]bool{}, root: map[string]bool{}, read: map[string]map[string]bool{}, readAs: map[string]catalogue.ArtifactContext{},
 		contextsAtHead: true}
 }
 
@@ -126,6 +132,16 @@ func (s *sourceInputs) ownHas(entries ...string) {
 	}
 }
 
+// rootHas adds entries, relative to the repository's root, to the module's build source in its own repository.
+func (s *sourceInputs) rootHas(entries ...string) {
+	if s == nil {
+		return
+	}
+	for _, e := range entries {
+		s.root[e] = true
+	}
+}
+
 // ownWhole says an artifact's build source in the module's own repository is not known: the module's
 // whole directory is its source, as it was before.
 func (s *sourceInputs) ownWhole() {
@@ -178,6 +194,9 @@ func (s *sourceInputs) buildSources() []BuildSource {
 		for e := range s.own {
 			own = append(own, withPrefix(s.prefix, e))
 		}
+		for e := range s.root {
+			own = append(own, e)
+		}
 		sort.Strings(own)
 		out = append(out, BuildSource{Paths: compactSorted(own)})
 	}

internal/builder/template.go

@@ -0,0 +1,95 @@
+package builder
+
+import (
+	"archive/tar"
+	"bytes"
+	"compress/gzip"
+	"crypto/sha256"
+	"encoding/hex"
+	"errors"
+	"fmt"
+	"io"
+	"path/filepath"
+
+	"github.com/novox/mesh-controller/internal/catalogue"
+)
+
+// withTemplateTexts is what was built with each template's text, for a module whose files name templates (novox/hq ADR
+// 0349 §2): its templates archive — the one built from its templates directory, files/ unless its manifest names
+// another (issue 731) — gains the text of every file in it, read back from the packed bytes, by its path inside the
+// archive. Resolve reads them into the files' content.
+//
+// **Read from the archive, proven by its digest.** The module's templates directory is packed again, as the build packs
+// it, and the bytes are read only when they hash to the digest the build made or took: a fresh build's own archive, or
+// a check's build a walk copied by digest without building (novox/hq ADR 0350 §2). Packing is deterministic, so one
+// source packs to one digest; a tree that packs to another is not the archive, and its text is refused.
+func withTemplateTexts(manifest catalogue.Manifest, within string, built []catalogue.Built) ([]catalogue.Built, error) {
+	if !manifest.Templated() {
+		return built, nil
+	}
+	name := catalogue.TemplatesArtifact(manifest)
+	at := -1
+	for i, b := range built {
+		if b.Name == name {
+			at = i
+		}
+	}
+	if name == "" || at < 0 {
+		return nil, fmt.Errorf("%s names templates and built no archive of %s/ to read them from",
+			manifest.Module, manifest.TemplatesDir())
+	}
+	body, err := pack(filepath.Join(within, filepath.FromSlash(manifest.TemplatesDir())))
+	if err != nil {
+		return nil, fmt.Errorf("%s: packing %s/ to read its templates back failed: %w", manifest.Module,
+			manifest.TemplatesDir(), err)
+	}
+	sum := sha256.Sum256(body)
+	digest := "sha256:" + hex.EncodeToString(sum[:])
+	if built[at].Digest != digest {
+		return nil, fmt.Errorf("%s: %s/ packs to the digest %s, and the archive %q built or taken is %s: the "+
+			"templates are read only from the archive the mesh records", manifest.Module, manifest.TemplatesDir(),
+			digest, name, orNone(built[at].Digest))
+	}
+	texts, err := unpackTexts(body)
+	if err != nil {
+		return nil, fmt.Errorf("%s: reading the archive %q back failed: %w", manifest.Module, name, err)
+	}
+	out := append([]catalogue.Built(nil), built...)
+	out[at].Texts = texts
+	return out, nil
+}
+
+// unpackTexts is every file of a packed archive (pack), by its path inside it.
+func unpackTexts(body []byte) (map[string]string, error) {
+	zipped, err := gzip.NewReader(bytes.NewReader(body))
+	if err != nil {
+		return nil, err
+	}
+	defer zipped.Close()
+	reader := tar.NewReader(zipped)
+	texts := map[string]string{}
+	for {
+		header, err := reader.Next()
+		if errors.Is(err, io.EOF) {
+			return texts, nil
+		}
+		if err != nil {
+			return nil, err
+		}
+		if header.Typeflag != tar.TypeReg {
+			continue
+		}
+		text, err := io.ReadAll(reader)
+		if err != nil {
+			return nil, err
+		}
+		texts[header.Name] = string(text)
+	}
+}
+
+func orNone(digest string) string {
+	if digest == "" {
+		return "no digest"
+	}
+	return digest
+}

internal/builder/template_test.go

@@ -0,0 +1,181 @@
+package builder
+
+import (
+	"context"
+	"crypto/sha256"
+	"encoding/hex"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/novox/mesh-controller/internal/catalogue"
+)
+
+// A module's files kept as template files in its repository (novox/hq ADR 0349 §2, design 57 package T1, issue
+// 654): the build packs files/ into the module's templates archive and reads each template's text back from the
+// packed bytes into the file's content, so the manifest the mesh holds is the one it would hold for the text inline.
+
+const templatedModule = `{"module":"meshboard","version":"1",
+  "build":{"artifacts":[
+    {"name":"server","kind":"image","from":"Dockerfile"},
+    {"name":"files","kind":"archive","from":"files"}]},
+  "resources":[
+    {"id":"svc","type":"container","name":"meshboard","artifact":"server"},
+    {"id":"conf","type":"file","path":"/etc/meshboard/meshboard.conf","template":"files/meshboard.conf"},
+    {"id":"deeper","type":"file","path":"/etc/meshboard/deeper.conf","template":"files/a/deeper.conf"}]}`
+
+var templatedFiles = map[string]string{
+	"Dockerfile": "FROM scratch", "files/meshboard.conf": "listen = 8080\n\"quoted\" é\n",
+	"files/a/deeper.conf": "deeper\n", "files/unused.conf": "packed, named by nothing",
+}
+
+func contentOf(t *testing.T, m catalogue.Manifest, id string) string {
+	t.Helper()
+	for _, r := range m.Resources {
+		if r["id"] == id {
+			if _, has := r[catalogue.TemplateField]; has {
+				t.Fatalf("%s still names its template in the built manifest: %v", id, r)
+			}
+			text, ok := r["content"].(string)
+			if !ok {
+				t.Fatalf("%s carries no content: %v", id, r)
+			}
+			return text
+		}
+	}
+	t.Fatalf("no resource %s in %v", id, m.Resources)
+	return ""
+}
+
+func TestABuildReadsEachTemplateBackFromItsArchive(t *testing.T) {
+	r, workspace := aRepository(t, templatedModule, templatedFiles)
+	got, err := Build(context.Background(), r.run, r, "https://forge.invalid/meshboard.git", "", "", workspace, nil,
+		Npmrc{}, GitCredential{}, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if text := contentOf(t, got.Manifest, "conf"); text != templatedFiles["files/meshboard.conf"] {
+		t.Fatalf("the template's text is %q, not the file's", text)
+	}
+	if text := contentOf(t, got.Manifest, "deeper"); text != templatedFiles["files/a/deeper.conf"] {
+		t.Fatalf("the template's text is %q, not the file's", text)
+	}
+	if r.archives["meshboard/files"] == "" {
+		t.Fatalf("the templates archive was not published: %v", r.archives)
+	}
+	if problem := catalogue.HeldTemplateProblem(got.Manifest); problem != "" {
+		t.Fatal(problem)
+	}
+}
+
+func TestABuildWhoseTemplateIsMissingFailsNamingIt(t *testing.T) {
+	files := map[string]string{}
+	for k, v := range templatedFiles {
+		files[k] = v
+	}
+	delete(files, "files/a/deeper.conf")
+	r, workspace := aRepository(t, templatedModule, files)
+	_, err := Build(context.Background(), r.run, r, "https://forge.invalid/meshboard.git", "", "", workspace, nil,
+		Npmrc{}, GitCredential{}, nil)
+	if err == nil || !strings.Contains(err.Error(), "files/a/deeper.conf") {
+		t.Fatalf("a build whose template is missing did not fail naming it: %v", err)
+	}
+}
+
+// A walk that takes its check's build copies the archive by digest and builds nothing: the templates are read back
+// from the tree packed again, which is the archive only when it packs to the digest taken.
+func TestAWalkTakingAChecksBuildReadsTheTemplatesBackToo(t *testing.T) {
+	withVersion(t, "builder-1")
+	contents := map[string]string{"mod/" + ManifestName: templatedModule}
+	for k, v := range templatedFiles {
+		contents["mod/"+k] = v
+	}
+	scratch := newScratch()
+	r, run, workspace := aModuleWith(t, "tree-one", contents)
+	checked := aCheckBuiltBy(t, scratch, r, run, workspace)
+
+	r, run, workspace = aModuleWith(t, "tree-one", contents)
+	got, err := BuildReusing(t.Context(), run, r, Reuse{Scratch: scratch, Pulls: []PullRef{aPull}, Named: named(checked)},
+		"https://forge.invalid/meshboard.git", "mod", "main", workspace, nil, Npmrc{}, GitCredential{}, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got.Reused == nil || len(r.archives) > 0 {
+		t.Fatalf("the walk built again: reused %+v, why %q, published %v", got.Reused, got.Why, r.archives)
+	}
+	if text := contentOf(t, got.Manifest, "conf"); text != templatedFiles["files/meshboard.conf"] {
+		t.Fatalf("the template's text is %q, not the file's", text)
+	}
+}
+
+// The tree packed again must be the archive taken; text read from anything else is not the archive's.
+func TestTemplateTextsAreRefusedWhenTheTreeDoesNotPackToTheDigestTaken(t *testing.T) {
+	m, err := catalogue.ParseManifest([]byte(templatedModule))
+	if err != nil {
+		t.Fatal(err)
+	}
+	within := writeTree(t, t.TempDir(), templatedFiles)
+	built := []catalogue.Built{{Name: "files", Kind: catalogue.ArtifactArchive, Digest: "sha256:" + strings.Repeat("0", 64)}}
+	if _, err := withTemplateTexts(m, within, built); err == nil || !strings.Contains(err.Error(), "digest") {
+		t.Fatalf("text was read from a tree that does not pack to the archive taken: %v", err)
+	}
+}
+
+// writeTree writes files under dir and answers dir.
+func writeTree(t *testing.T, dir string, files map[string]string) string {
+	t.Helper()
+	for name, body := range files {
+		full := filepath.Join(dir, filepath.FromSlash(name))
+		if err := os.MkdirAll(filepath.Dir(full), 0o755); err != nil {
+			t.Fatal(err)
+		}
+		if err := os.WriteFile(full, []byte(body), 0o644); err != nil {
+			t.Fatal(err)
+		}
+	}
+	return dir
+}
+
+// A module whose files/ is an archive unpacked onto the machine keeps its templates in a directory it names (issue
+// 731): the build reads each template back from the archive packed from that directory, and files/ is packed as it
+// was, its templates nowhere in it.
+const unpackingModule = `{"module":"meshboard","version":"1",
+  "templates":"templates",
+  "build":{"artifacts":[
+    {"name":"scripts","kind":"archive","from":"files"},
+    {"name":"templates","kind":"archive","from":"templates"}]},
+  "resources":[
+    {"id":"scripts","type":"archive","path":"/usr/local/lib/meshboard","artifact":"scripts"},
+    {"id":"conf","type":"file","path":"/etc/meshboard/meshboard.conf","template":"templates/meshboard.conf"}]}`
+
+func TestABuildReadsEachTemplateBackFromTheTemplatesDirectoryItsManifestNames(t *testing.T) {
+	files := map[string]string{"files/bin/meshboard-hook": "#!/bin/sh\n", "templates/meshboard.conf": "listen = 8080\n"}
+	r, workspace := aRepository(t, unpackingModule, files)
+	got, err := Build(context.Background(), r.run, r, "https://forge.invalid/meshboard.git", "", "", workspace, nil,
+		Npmrc{}, GitCredential{}, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if text := contentOf(t, got.Manifest, "conf"); text != files["templates/meshboard.conf"] {
+		t.Fatalf("the template's text is %q, not the file's", text)
+	}
+	if got.Manifest.Templates != "" {
+		t.Fatalf("the built manifest still names its templates directory: %q", got.Manifest.Templates)
+	}
+	// files/ packs exactly as it would with no templates beside it.
+	alone, err := pack(writeTree(t, t.TempDir(), map[string]string{"bin/meshboard-hook": "#!/bin/sh\n"}))
+	if err != nil {
+		t.Fatal(err)
+	}
+	sum := sha256.Sum256(alone)
+	packed := ""
+	for _, b := range got.Built {
+		if b.Name == "scripts" {
+			packed = b.Digest
+		}
+	}
+	if packed != "sha256:"+hex.EncodeToString(sum[:]) {
+		t.Fatalf("files/ packed to %q, not to what it packs to alone", packed)
+	}
+}