Function UpdateLocalCopyBranch

internal/database/repo.go:658–696

UpdateLocalCopy fetches latest changes of given branch from repoPath to localPath. It creates a new clone if local copy does not exist, but does not checks out to a specific branch if the local copy belongs to a wiki. For existing local copy, it checks out to target branch by default, and safe to as

(repoPath, localPath, branch string, isWiki bool)

// assume subsequent operations are against target branch when caller has confidence
// about no race condition.
func UpdateLocalCopyBranch(repoPath, localPath, branch string, isWiki bool) (err error) {
	if !osutil.Exist(localPath) {
		// Checkout to a specific branch fails when wiki is an empty repository.
		if isWiki {
			branch = ""
		}
		if err = git.Clone(repoPath, localPath, git.CloneOptions{
			Branch:  branch,
			Timeout: time.Duration(conf.Git.Timeout.Clone) * time.Second,
		}); err != nil {
			return errors.Newf("git clone [branch: %s]: %v", branch, err)
		}
		return nil
	}

	gitRepo, err := git.Open(localPath)
	if err != nil {
		return errors.Newf("open repository: %v", err)
	}

	if err = gitRepo.Fetch(git.FetchOptions{
		Prune: true,
	}); err != nil {
		return errors.Newf("fetch: %v", err)
	}

	if err = gitRepo.Checkout(branch); err != nil {
		return errors.Newf("checkout [branch: %s]: %v", branch, err)
	}

	// Reset to align with remote in case of force push.
	rev := "origin/" + branch
	if err = gitRepo.Reset(rev, git.ResetOptions{
		Hard: true,
	}); err != nil {
		return errors.Newf("reset [revision: %s]: %v", rev, err)
	}
	return nil
}

// UpdateLocalCopyBranch makes sure local copy of repository in given branch is up-to-date.
func (r *Repository) UpdateLocalCopyBranch(branch string) error {