nektos/act · error

HEAD sha1 could not be resolved

Error message

HEAD sha1 could not be resolved

What it means

FindGitRevision resolves HEAD via go-git; if the HEAD reference exists but its hash is all-zero, the commit cannot be identified. A zero hash means the repository has no commits on the current branch — an 'unborn' HEAD, typical of a freshly git init'ed repo with everything still uncommitted.

Source

Thrown at pkg/common/git/git.go:77

		file,
		&git.PlainOpenOptions{
			DetectDotGit:          true,
			EnableDotGitCommonDir: true,
		},
	)

	if err != nil {
		logger.WithError(err).Error("path", file, "not located inside a git repository")
		return "", "", err
	}

	head, err := gitDir.Reference(plumbing.HEAD, true)
	if err != nil {
		return "", "", err
	}

	if head.Hash().IsZero() {
		return "", "", fmt.Errorf("HEAD sha1 could not be resolved")
	}

	hash := head.Hash().String()

	logger.Debugf("Found revision: %s", hash)
	return hash[:7], strings.TrimSpace(hash), nil
}

// FindGitRef get the current git ref
func FindGitRef(ctx context.Context, file string) (string, error) {
	logger := common.Logger(ctx)

	logger.Debugf("Loading revision from git directory")
	_, ref, err := FindGitRevision(ctx, file)
	if err != nil {
		return "", err
	}

View on GitHub (pinned to 4f41128141)

Solutions

1. Make at least one commit in the repository (git add -A && git commit -m 'init') and rerun act
2. If testing workflow syntax only, bypass ref resolution features that need the SHA
3. Verify with 'git rev-parse HEAD' — it should print a hash, not fail

Example fix

# before
git init && cp -r myworkflow .github/workflows/ && act  # zero-hash HEAD

# after
git init && git add -A && git commit -m 'init' && act

// before running act, ensure HEAD resolves
if out, err := exec.Command("git", "-C", dir, "rev-parse", "HEAD").Output(); err != nil {
    return fmt.Errorf("repo has no commits; commit first: %w", err)
} else {
    log.Printf("HEAD = %s", strings.TrimSpace(string(out)))
}

When it happens

Trigger: Running act in a directory that is a git repo with zero commits (git init; add files; never commit), or a worktree/repo whose HEAD symbolic ref points at a branch that was never created by a commit. Any act feature needing GITHUB_SHA (action ref checkout, default ref resolution) hits it.

Common situations: Quick experiments: user inits a repo, drops a workflow in .github/workflows/, runs act before the first commit; CI checkouts of empty repos; scaffolding tools that git init but defer the first commit.

Related errors

• failed to identify reference (tag/branch) for the checked-ou
• remote '%s' exists but has no URL
• GoGitActionCache failed to open bare git %s with ref %s at %
• GoGitActionCache failed to create remote %s with ref %s at %
• GoGitActionCache failed to fetch %s with ref %s at %s: %w

AI-assisted analysis of nektos/act@4f41128141 (2026-08-15). Data as JSON: /api/errors/0c09fc0732b1dd0d. Report an issue: GitHub.