gastownhall/beads · warning

unexpected git rev-parse output

Error message

unexpected git rev-parse output

What it means

mainRepoRootForPath expects `git rev-parse --show-toplevel --git-common-dir` to print exactly two lines: the toplevel and the common dir. If the trimmed output splits into fewer than two lines, bd returns "unexpected git rev-parse output" — git succeeded but its output shape was not what this code contractually expects.

Source

Thrown at internal/beads/fingerprint.go:196

// of --git-common-dir (the main repo root), not --show-toplevel (the
// worktree root). For regular repos, both are equivalent.
//
// GH#2867: This ensures fingerprint computation uses a stable path that is
// the same across all worktrees sharing a database.
func mainRepoRootForPath(repoPath string) (string, error) {
	// Get both toplevel and common-dir in one pass to detect worktrees.
	cmd := exec.Command("git", "rev-parse", "--show-toplevel", "--git-common-dir")
	if repoPath != "" {
		cmd.Dir = repoPath
	}
	output, err := cmd.Output()
	if err != nil {
		return "", fmt.Errorf("not a git repository: %w", err)
	}

	lines := strings.SplitN(strings.TrimSpace(string(output)), "\n", 2)
	if len(lines) < 2 {
		return "", fmt.Errorf("unexpected git rev-parse output")
	}

	toplevel := strings.TrimSpace(lines[0])
	commonDir := strings.TrimSpace(lines[1])

	// Resolve to absolute paths for comparison.
	absToplevel, err := filepath.Abs(toplevel)
	if err != nil {
		return toplevel, nil
	}

	// commonDir may be relative; resolve relative to the working directory
	// (repoPath if set, else CWD).
	if !filepath.IsAbs(commonDir) {
		base := repoPath
		if base == "" {
			base, _ = os.Getwd()
		}

View on GitHub (pinned to 71377f2769)

Solutions

1. Run from inside a normal (non-bare) work tree instead of the .git directory or a bare repo
2. Test `git rev-parse --show-toplevel --git-common-dir` manually in the affected path and compare output
3. Remove git aliases/shims or GIT_* env overrides (GIT_DIR, GIT_WORK_TREE) that alter rev-parse output
4. Upgrade/downgrade to a standard git version and retry

Example fix

// before (inside bare repo)
cd /srv/repo.git && bd ...
// after
cd /srv/repo-worktree && bd ...

out, err := exec.Command("git", "-C", path, "rev-parse", "--show-toplevel", "--git-common-dir").Output()
if err != nil || len(strings.SplitN(strings.TrimSpace(string(out)), "\n", 2)) < 2 {
    // output shape unexpected; run from a normal work tree
}

root, err := beads.ComputeRepoIDForPath(path)
if err != nil && strings.Contains(err.Error(), "unexpected git rev-parse output") {
    return fmt.Errorf("run from inside a normal (non-bare) work tree: %w", err)
}

When it happens

Trigger: git rev-parse succeeds but emits a single line or empty output — e.g. run inside .git dir or bare repo where toplevel is empty/absent, unusual git versions/config (quotePath, aliases), or a wrapper script replacing git with different output.

Common situations: Running from inside the .git directory or a bare repository; a global git alias/shim intercepting rev-parse; heavily modified GIT_* environment variables; very old or patched git builds with different multi-command rev-parse behavior.

Related errors

• failed to untrack redirect file: %w
• failed to untrack last-touched file: %w
• failed to untrack files: %w %s
• failed to init git in planning repo: %w
• unexpected porcelain status record %q

AI-assisted analysis of gastownhall/beads@71377f2769 (2026-08-30). Data as JSON: /api/errors/1c08d67afc5a6d58. Report an issue: GitHub.