Simplify previous manifest collection

internal/stage/publish.go

@@ -111,13 +111,10 @@ func (publishStage) Run(ctx context.Context, env *Env, m *manifest.Manifest) (*S
 		return nil, fmt.Errorf("publish: object store does not support verified source uploads")
 	}
 	sessionPaths := publishSessionPaths(env, m)
-	previousFiles, previousManifestFile, err := collectPublishPreviousFiles(ctx, sessionPaths.PreviousDir)
+	previousFiles, err := collectPublishPreviousFiles(ctx, sessionPaths.PreviousDir)
 	if err != nil {
 		return nil, fmt.Errorf("publish: collect previous files: %w", err)
 	}
-	if previousManifestFile != nil {
-		defer previousManifestFile.Close()
-	}
 	previousSources, err := openPublishRunFiles(sessionPaths.PreviousDir, previousFiles)
 	if err != nil {
 		return nil, fmt.Errorf("publish: verify previous files: %w", err)
@@ -877,37 +874,33 @@ func collectPublishRunFiles(runRoot string, sessionManifest *manifest.Manifest)
 	return out, nil
 }
 
-func collectPublishPreviousFiles(ctx context.Context, previousDir string) ([]publishUploadFile, *os.File, error) {
+func collectPublishPreviousFiles(ctx context.Context, previousDir string) ([]publishUploadFile, error) {
 	previousDir = filepath.Clean(strings.TrimSpace(previousDir))
 	if previousDir == "" || previousDir == "." {
-		return nil, nil, fmt.Errorf("previous directory is required")
+		return nil, fmt.Errorf("previous directory is required")
 	}
 	info, err := os.Lstat(previousDir)
 	if errors.Is(err, os.ErrNotExist) {
-		return nil, nil, nil
+		return nil, nil
 	}
 	if err != nil {
-		return nil, nil, fmt.Errorf("inspect previous directory: %w", err)
+		return nil, fmt.Errorf("inspect previous directory: %w", err)
 	}
 	if info.Mode()&os.ModeSymlink != 0 || !info.IsDir() {
-		return nil, nil, fmt.Errorf("previous directory is not a regular directory")
+		return nil, fmt.Errorf("previous directory is not a regular directory")
 	}
 
 	manifestFile, err := openPublishOutputSource(filepath.Join(previousDir, "manifest.json"))
 	if err != nil {
 		if errors.Is(err, os.ErrNotExist) {
-			return nil, nil, nil
+			return nil, nil
 		}
-		return nil, nil, fmt.Errorf("open previous manifest: %w", err)
+		return nil, fmt.Errorf("open previous manifest: %w", err)
 	}
+	defer manifestFile.Close()
 	previousManifest, err := (&manifest.LocalStore{}).LoadReader(ctx, manifestFile)
 	if err != nil {
-		_ = manifestFile.Close()
-		return nil, nil, fmt.Errorf("load previous manifest: %w", err)
-	}
-	if _, err := manifestFile.Seek(0, io.SeekStart); err != nil {
-		_ = manifestFile.Close()
-		return nil, nil, fmt.Errorf("rewind previous manifest: %w", err)
+		return nil, fmt.Errorf("load previous manifest: %w", err)
 	}
 
 	files := map[string]publishUploadFile{
@@ -934,13 +927,11 @@ func collectPublishPreviousFiles(ctx context.Context, previousDir string) ([]pub
 	}
 	for _, artifact := range previousManifest.Artifacts {
 		if err := add(artifact.ArchivePath, artifact.Checksum); err != nil {
-			_ = manifestFile.Close()
-			return nil, nil, err
+			return nil, err
 		}
 		if artifact.ArchivePath == "" {
 			if err := add(artifact.LocalPath, artifact.Checksum); err != nil {
-				_ = manifestFile.Close()
-				return nil, nil, err
+				return nil, err
 			}
 		}
 	}
@@ -950,20 +941,17 @@ func collectPublishPreviousFiles(ctx context.Context, previousDir string) ([]pub
 		}
 		for _, artifact := range record.Outputs {
 			if err := add(artifact.ArchivePath, artifact.Checksum); err != nil {
-				_ = manifestFile.Close()
-				return nil, nil, err
+				return nil, err
 			}
 			if artifact.ArchivePath == "" {
 				if err := add(artifact.LocalPath, artifact.Checksum); err != nil {
-					_ = manifestFile.Close()
-					return nil, nil, err
+					return nil, err
 				}
 			}
 		}
 		for _, path := range append(append([]string(nil), record.Logs...), record.GeneratedConfigs...) {
 			if err := add(path, ""); err != nil {
-				_ = manifestFile.Close()
-				return nil, nil, err
+				return nil, err
 			}
 		}
 	}
@@ -972,7 +960,7 @@ func collectPublishPreviousFiles(ctx context.Context, previousDir string) ([]pub
 		out = append(out, file)
 	}
 	sort.Slice(out, func(i, j int) bool { return out[i].RelativePath < out[j].RelativePath })
-	return out, manifestFile, nil
+	return out, nil
 }
 
 func openPublishRunFiles(runRoot string, files []publishUploadFile) ([]*os.File, error) {