The indexer counts the modules on each old section, a tool reads it, and the judge refuses a section at 0 outside the foundation (issue 1966 D4)

modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer-tools/main.go

@@ -22,9 +22,22 @@ import (
 type asker func(key string, value []byte) (index.TakeInAsk, error)
 
 // Tools are the indexer's tools.
-func Tools(ask asker, now func() time.Time) []stdio.Tool {
+func Tools(ask asker, now func() time.Time, counts func() (index.OldSectionsCount, error)) []stdio.Tool {
 	str := func(args map[string]any, k string) string { s, _ := args[k].(string); return strings.TrimSpace(s) }
 	return []stdio.Tool{
+		{Name: index.OldSectionsTool,
+			Description: "How many accepted modules use each old section of a manifest (state, logs, streams, objects), the foundation " +
+				"(nats, mesh-grants, the indexer) left out: the count the judge refuses a use of a section at 0 by, as modules move " +
+				"their bus state into `requires` by template. Read from the indexer's oldsections state, kept as the indexer judges " +
+				"the manifests; an empty answer means the indexer has not judged since it started.",
+			Input: map[string]any{"type": "object", "properties": map[string]any{}},
+			Run: func(map[string]any) (any, error) {
+				c, err := counts()
+				if err != nil {
+					return nil, err
+				}
+				return c.Counts, nil
+			}},
 		{Name: index.TakeInTool,
 			Description: "Take a registered module in now: the indexer reads its manifest from the repository and commit the controller's " +
 				"build records register it from (at the head the gate's source names, when it names one), whatever it tried before, and " +
@@ -105,8 +118,22 @@ func askTakeIn(s stdio.KeptState, bound time.Duration) asker {
 	}
 }
 
+// heldCounts reads the count of the old sections the indexer keeps.
+func heldCounts(s stdio.KeptState) func() (index.OldSectionsCount, error) {
+	return func() (index.OldSectionsCount, error) {
+		e, err := s.Get(index.OldSectionsKey)
+		if err != nil {
+			return index.OldSectionsCount{}, fmt.Errorf("reading %s.%s: %w", index.OldSectionsBucket, index.OldSectionsKey, err)
+		}
+		if e == nil {
+			return index.OldSectionsCount{}, fmt.Errorf("the indexer has not counted the old sections yet: %s holds no %s", index.OldSectionsBucket, index.OldSectionsKey)
+		}
+		return index.DecodeOldSections(e.Value)
+	}
+}
+
 func main() {
-	if err := stdio.Serve("", Tools(askTakeIn(stdio.State(index.TakeInsState), 25*time.Second), time.Now)); err != nil {
+	if err := stdio.Serve("", Tools(askTakeIn(stdio.State(index.TakeInsState), 25*time.Second), time.Now, heldCounts(stdio.State(index.OldSectionsState)))); err != nil {
 		fmt.Fprintf(os.Stderr, "[mesh-delivery-indexer-tools] %v\n", err)
 		os.Exit(1)
 	}

modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/main.go

@@ -296,7 +296,10 @@ func run(ctx context.Context, getenv func(string) string, logOut io.Writer) erro
 	// The published packages (ADR 0593 §2): a state this delivery brings, bound when it appears; until then every
 	// fingerprint takes the version line.
 	packages := process.AwaitBucket(ctx, js, conn, delivery.PackagesBucket, "no package is published, so every fingerprint takes the version line", logger.Printf)
-	ix := &index.Indexer{Store: kvStore{candidates}, Modules: kvStore{modules}, Manifests: kvStore{manifests}, Taken: awaitedStore{taken}, Builds: known,
+	// How many modules use each old section (issue 1966 D4): a state this delivery brings, bound when it appears; until then
+	// the judge refuses no use of an old section.
+	oldSections := process.AwaitBucket(ctx, js, conn, index.OldSectionsBucket, "the count of the old sections is not kept, so the judge refuses no use of one", logger.Printf)
+	ix := &index.Indexer{OldSections: awaitedStore{oldSections}, Store: kvStore{candidates}, Modules: kvStore{modules}, Manifests: kvStore{manifests}, Taken: awaitedStore{taken}, Builds: known,
 		Verdicts: awaitedStore{verdicts}, SayRefused: sayRefused(js, cred, logger.Printf), SayAccepted: sayAccepted(js, cred, logger.Printf),
 		Predefined: awaitedStore{predefined}, ConfigCandidates: awaitedStore{configCandidates}, Logf: logger.Printf,
 		Named: namedVia(calls.Call), Trunk: trunkVia(calls.Call), Contains: containsVia(calls.Call), Read: readVia(calls.Call),