Indexer: read a registered module at the source's head when it names one, else at the registered commit

modules/mesh-delivery-indexer/internal/index/registered.go

@@ -11,8 +11,8 @@ import (
 // A module registered in the catalogue from its own repository (the operator registers it with the repository and the
 // path of its manifest) had no manifest here: the indexer learns a repository only from a merged message, and no merge
 // followed the registration. The controller's outcome records name each registered module's repository, directory and
-// commit (builds.go Registered), so the indexer reads that module's manifest  writes the
-// same keys a merge writes. A later merge to the repository's trunk reaches the module through the forge bridge's merged
+// commit (builds.go Registered), so the indexer reads that module's manifest at the repository's head (the gate's source names it) or, with none named, at the
+// registered commit, and writes the same keys a merge writes. A later merge to the repository's trunk reaches the module through the forge bridge's merged
 // message as for every other repository.
 
 // RepoRead is a repository at a commit as the forge bridge reads it for a merged message: the root tree, the tree of each
@@ -25,7 +25,7 @@ type RepoRead struct {
 }
 
 // IndexRegistered writes the module of a registration as a merge of its repository would, when the modules bucket holds
-// none of that name. Its commit is the registration's; a repository the gate's source names is left to the merges. The
+// none of that name. Its commit is the head the gate's source names for the repository, else the registration's. The
 // repository's other modules are neither written nor dropped: they are the merges'. A manifest that is not at the path or
 // names another module is said and left.
 func (ix *Indexer) IndexRegistered(ctx context.Context, r Registration) error {
@@ -48,19 +48,15 @@ func (ix *Indexer) IndexRegistered(ctx context.Context, r Registration) error {
 	if dir == delivery.RootPath {
 		dir = ""
 	}
-	// A repository the gate's source names is the merges': an unheld module there was removed by a merge, or its record is
-	// stale, and reading the repository for it would cost a forge call for each such module at every start.
+	// The head the gate's source names for the repository, when it names one, else the registration's commit. A module a
+	// merge removed is absent at the head and is said and left.
 	ix.mu.Lock()
-	owned := false
-	for repo := range ix.source.heads {
-		if delivery.SameRepository(repo, r.Repository) {
-			owned = true
+	for repo, head := range ix.source.heads {
+		if delivery.SameRepository(repo, r.Repository) && head != "" {
+			commit = head
 		}
 	}
 	ix.mu.Unlock()
-	if owned {
-		return nil
-	}
 	if repository == "" || commit == "" {
 		ix.logf("%s: registered with no repository or commit, so its manifest is not read", r.Module)
 		return nil

modules/mesh-delivery-indexer/internal/index/registered_test.go

@@ -41,7 +41,7 @@ func TestARegisteredModuleIsIndexedFromItsRepository(t *testing.T) { // the gran
 			read: RepoRead{Root: "r0", Trees: map[string]string{"": "t1"}, Manifests: map[string]string{"": snake}}},
 		{name: "a record of another branch", path: "", ref: "feat/x",
 			read: RepoRead{Root: "r0", Trees: map[string]string{"": "t1"}, Manifests: map[string]string{"": snake}}},
-		{name: "a repository the gate's source names is the merges'", path: "", heads: map[string]string{"jschoubben/snake": h2},
+		{wantRead: true, name: "a repository the source names, the module unheld and present at the head", path: "", want: true, heads: map[string]string{"jschoubben/snake": h2},
 			read: RepoRead{Root: "r0", Trees: map[string]string{"": "t1"}, Manifests: map[string]string{"": snake}}},
 		{wantRead: true, name: "a forge that cannot say", path: "", err: errors.New("down")},
 	} {
@@ -74,6 +74,13 @@ func TestARegisteredModuleIsIndexedFromItsRepository(t *testing.T) { // the gran
 			if (err != nil) != (tc.err != nil) {
 				t.Fatalf("error = %v", err)
 			}
+			wantCommit := "7a74cee83f88e6585a5511c3cc53bdf0f5303d20" // the record's
+			if tc.heads != nil {
+				wantCommit = h2 // the source's head
+			}
+			if tc.wantRead && asked.sha != wantCommit {
+				t.Errorf("the forge was asked at %s, want %s", asked.sha, wantCommit)
+			}
 			wantReads := 1
 			if !tc.wantRead {
 				wantReads = 0
@@ -86,7 +93,7 @@ func TestARegisteredModuleIsIndexedFromItsRepository(t *testing.T) { // the gran
 			}
 			m, ok := moduleOf(t, mods, "snake")
 			if tc.want {
-				if !ok || m.Manifest == "" || m.Repository != "jschoubben/snake" || m.Commit != "7a74cee83f88e6585a5511c3cc53bdf0f5303d20" || m.Path != pathOf(dirOf(tc.path)) {
+				if !ok || m.Manifest == "" || m.Repository != "jschoubben/snake" || m.Commit != wantCommit || m.Path != pathOf(dirOf(tc.path)) {
 					t.Fatalf("modules.snake = %+v, found %v", m, ok)
 				}
 				if len(ix.Manifests.(*memStore).vals) != 1 {