Function gitApplyPatchFromFile

core/changeset.go:1280–1331

gitApplyPatchFromFile streams the patch to avoid loading it entirely into memory.

(ctx context.Context, dir string, patch *File)

// gitApplyPatchFromFile streams the patch to avoid loading it entirely into memory.
func gitApplyPatchFromFile(ctx context.Context, dir string, patch *File) error {
	if patch == nil {
		return nil
	}

	patchRef, _ := patch.Snapshot.Peek()
	if patchRef == nil {
		return fmt.Errorf("evaluate patch ref: nil")
	}
	patchPathSelector, _ := patch.File.Peek()

	return MountRef(ctx, patchRef, func(patchMount string, _ *mount.Mount) error {
		patchPath, err := containerdfs.RootPath(patchMount, patchPathSelector)
		if err != nil {
			return err
		}

		// Check if patch file is empty
		info, err := os.Stat(patchPath)
		if err != nil {
			return fmt.Errorf("stat patch file: %w", err)
		}
		if info.Size() == 0 {
			return nil
		}

		tempPatch := filepath.Join(dir, ".dagger-patch")
		srcFile, err := os.Open(patchPath)
		if err != nil {
			return fmt.Errorf("open patch file: %w", err)
		}
		defer srcFile.Close()

		dstFile, err := os.Create(tempPatch)
		if err != nil {
			return fmt.Errorf("create temp patch file: %w", err)
		}

		if _, err := io.Copy(dstFile, srcFile); err != nil {
			dstFile.Close()
			os.Remove(tempPatch)
			return fmt.Errorf("copy patch file: %w", err)
		}
		if err := dstFile.Close(); err != nil {
			os.Remove(tempPatch)
			return fmt.Errorf("close temp patch file: %w", err)
		}

		defer os.Remove(tempPatch)
		return runGit(ctx, dir, "apply", "--allow-empty", tempPatch)
	}, mountRefAsReadOnly)
}

func initGitRepo(ctx context.Context, dir string) error {
	if err := runGit(ctx, dir, "init"); err != nil {