autogen activation

internal/topdata/autogen.go

@@ -225,6 +225,9 @@ func autogenConsumerTargetsDataset(dataset nativeCollectedDataset, consumer proj
 }
 
 func resolveAutogenConsumerManifest(p *project.Project, consumer project.AutogenConsumerConfig, progress func(string)) (*autogenManifest, error) {
+	if manifestFile := strings.TrimSpace(consumer.ManifestFile); manifestFile != "" {
+		return readAutogenConsumerManifestFile(p, consumer, manifestFile, progress)
+	}
 	overrideRoot, err := resolveAutogenLocalOverrideRoot(p, consumer)
 	if err != nil {
 		return nil, err
@@ -242,6 +245,37 @@ func resolveAutogenConsumerManifest(p *project.Project, consumer project.Autogen
 	return resolveReleasedAutogenManifest(p, consumer, progress)
 }
 
+// readAutogenConsumerManifestFile reads a pre-resolved autogenManifest JSON from
+// a local file (relative paths resolve against the project root). A missing file
+// is an ignorable-optional condition — it returns errAutogenManifestUnavailable
+// so an optional consumer fails open and preserves its pinned lock IDs. A present
+// but malformed file, or an id that disagrees with the consumer's producer, is a
+// hard error.
+func readAutogenConsumerManifestFile(p *project.Project, consumer project.AutogenConsumerConfig, manifestFile string, progress func(string)) (*autogenManifest, error) {
+	path := manifestFile
+	if !filepath.IsAbs(path) {
+		path = filepath.Join(p.Root, path)
+	}
+	raw, err := os.ReadFile(path)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return nil, unavailableAutogenManifest(fmt.Errorf("manifest file %s not found", path))
+		}
+		return nil, fmt.Errorf("read autogen manifest file %s: %w", path, err)
+	}
+	var manifest autogenManifest
+	if err := json.Unmarshal(raw, &manifest); err != nil {
+		return nil, fmt.Errorf("parse autogen manifest file %s: %w", path, err)
+	}
+	if manifest.ID != "" && manifest.ID != consumer.Producer {
+		return nil, fmt.Errorf("autogen manifest file %s declared id %q, expected %q", path, manifest.ID, consumer.Producer)
+	}
+	if progress != nil {
+		progress(fmt.Sprintf("Reading local autogen manifest for %s from %s...", consumer.ID, path))
+	}
+	return &manifest, nil
+}
+
 func resolveAutogenLocalOverrideRoot(p *project.Project, consumer project.AutogenConsumerConfig) (string, error) {
 	root := strings.TrimSpace(consumer.LocalOverrideRoot)
 	if root != "" {