cleanup-branch

What this skill does

Clean up branches that have been merged or are no longer needed.
Handles squash merges correctly and cleans up associated worktrees.

## Use Case

- Remove merged feature branches after PR merge (including squash merge)
- Clean up stale branches that haven't been used
- Clean up orphaned git worktrees
- Keep repository tidy with minimal branch clutter

## Process

1. **Fetch latest**: `git fetch --prune origin`
2. **Check worktrees**: `git worktree list` to find associated worktrees
3. **Detect merged branches**: Use `gh` CLI for accurate squash merge detection
4. **Show preview**: List branches and worktrees to be deleted
5. **Confirm with user**: Ask before deletion
6. **Delete**: Remove worktrees first, then branches

## Branch Detection

### Step 1: Check gh CLI availability

```bash
command -v gh &>/dev/null && gh auth status &>/dev/null
```

### Step 2a: With gh CLI (preferred)

For each local branch (excluding protected), check if its PR was merged:

```bash
gh pr list --head <branch> --state merged --json number,title --limit 1
```

- Returns results → branch's PR was merged (works for squash merge, rebase merge, merge commit)
- Returns empty → branch has no merged PR, skip unless stale

### Step 2b: Without gh CLI (fallback)

List all non-protected local branches and show to user for manual selection.
Use `git branch -D` (force delete) since `git branch -d` cannot detect squash merges.

### Step 3: Stale Branch Detection (Optional)

Branches with no commits in 30+ days and no merged PR:
```bash
git for-each-ref --sort=-committerdate --format='%(refname:short) %(committerdate:relative)' refs/heads/
```

## Worktree Cleanup

Before deleting any branch, check for associated worktrees:

```bash
git worktree list --porcelain
```

If a target branch has a linked worktree:
1. Show the worktree path to user
2. Ask for confirmation
3. Run `git worktree remove <path>` (or `--force` if dirty)
4. Then proceed with branch deletion

Also detect orphaned worktrees (worktree directory missing):
```bash
git worktree prune
```

## Safety Features

- **Protected branches**: Never delete main, master, develop
- **Current branch**: Never delete the branch you're on
- **Worktree check**: Always check and clean worktrees before branch deletion
- **Preview first**: Always show what will be deleted before doing it
- **User confirmation**: Require explicit yes before deletion
- **Remote caution**: Extra confirmation for remote branch deletion
- **Dirty worktree**: Warn if worktree has uncommitted changes, require explicit force

## Execution Steps

1. Run `git fetch --prune origin` to sync
2. Run `git worktree prune` to clean orphaned worktree references
3. Detect default branch (main or master)
4. Check `gh` CLI availability
5. Find merged branches:
   - With `gh`: iterate local branches, check `gh pr list --head <branch> --state merged`
   - Without `gh`: list all non-protected branches for user selection
6. Run `git worktree list --porcelain` to find worktrees linked to target branches
7. Show preview to user (branches + worktrees)
8. Ask for confirmation
9. Delete in order:
   - Worktrees: `git worktree remove <path>`
   - Local branches: `git branch -D <branch>`
   - Remote branches (if --remote): `git push origin --delete <branch>`

## Examples

**Basic cleanup (with gh):**
```
/stylish-git:cleanup-branch
→ Fetching and analyzing branches...
→ Checking merged PRs via GitHub...
→ Found 3 merged branches:

  Merged PR (squash/merge):
  - feature/add-button (#42)
  - feature/fix-header (#38)
  - bugfix/typo (#45)

  Protected (skipped):
  - main
  - develop

→ Delete these 3 local branches? (y/n)
→ Deleted 3 branches ✅
```

**With worktree cleanup:**
```
/stylish-git:cleanup-branch
→ Fetching and analyzing branches...
→ Found 2 merged branches:

  Merged PR:
  - feature/add-button (#42)
  - feature/new-page (#50)

  Linked worktrees:
  - feature/new-page → ~/projects/repo-feature-new-page

→ Delete 2 branches and 1 worktree? (y/n)
→ Removed worktree: ~/projects/repo-feature-new-page
→ Deleted 2 branches ✅
```

**Without gh CLI (fallback):**
```
/stylish-git:cleanup-branch
→ gh CLI not available, showing all non-protected branches
→ Local branches:
  1. feature/add-button (3 days ago)
  2. feature/old-experiment (30 days ago)
  3. bugfix/typo (1 day ago)

→ Enter branch numbers to delete (e.g. 1,2): 1,2
→ Deleted 2 branches ✅
```

**With remote cleanup:**
```
/stylish-git:cleanup-branch --remote
→ Found 5 merged branches:

  Local:
  - feature/add-button (#42)
  - feature/fix-header (#38)

  Remote:
  - origin/feature/old-feature
  - origin/feature/completed-work
  - origin/bugfix/fixed

→ Delete 2 local + 3 remote branches? (y/n)
→ Deleted 5 branches ✅
```

**Nothing to clean:**
```
/stylish-git:cleanup-branch
→ Fetching and analyzing branches...
→ No merged branches found ✅
→ Repository is clean
```