Function executeLocalRepoSync

pkg/cmd/repo/sync/sync.go:221–272

(srcRepo ghrepo.Interface, remote string, opts *SyncOptions)

var divergingError = errors.New("diverging changes")

func executeLocalRepoSync(srcRepo ghrepo.Interface, remote string, opts *SyncOptions) error {
	git := opts.Git
	branch := opts.Branch
	useForce := opts.Force

	hasLocalBranch := git.HasLocalBranch(branch)
	if hasLocalBranch {
		fastForward, err := git.IsAncestor(branch, "FETCH_HEAD")
		if err != nil {
			return err
		}
		if !fastForward && !useForce {
			return divergingError
		}
		if fastForward && useForce {
			useForce = false
		}
	}

	currentBranch, err := git.CurrentBranch()
	if err != nil && !errors.Is(err, gitpkg.ErrNotOnAnyBranch) {
		return err
	}
	if currentBranch == branch {
		if isDirty, err := git.IsDirty(); err == nil && isDirty {
			return fmt.Errorf("refusing to sync due to uncommitted/untracked local changes\ntip: use `git stash --all` before retrying the sync and run `git stash pop` afterwards")
		} else if err != nil {
			return err
		}
		if useForce {
			if err := git.ResetHard("FETCH_HEAD"); err != nil {
				return err
			}
		} else {
			if err := git.MergeFastForward("FETCH_HEAD"); err != nil {
				return err
			}
		}
	} else {
		if hasLocalBranch {
			if err := git.UpdateBranch(branch, "FETCH_HEAD"); err != nil {
				return err
			}
		} else {
			if err := git.CreateBranch(branch, "FETCH_HEAD", fmt.Sprintf("%s/%s", remote, branch)); err != nil {
				return err
			}
		}
	}

	return nil
}

// ExecuteRemoteRepoSync will take several steps to sync the source and destination repositories.
// First it will try to use the merge-upstream API endpoint. If this fails due to merge conflicts