Prune Merged Branches

Remove local branches that have already been merged into remote main.

Usage

•/git-prune-merged - List and prune merged branches (with confirmation)
•/git-prune-merged --dry-run - Only list branches that would be pruned

Instructions

•
Fetch latest from remote:
bash
```
git fetch origin main --prune
```
•
Find merged branches (store as MERGED_BRANCHES):

Detect branches merged via two methods:

Method A - Regular merges:
bash
```
git branch --merged origin/main | grep -v '^\*' | grep -v 'main' | grep -v 'master'
```
Method B - Squash merges (remote branch deleted after PR merge):
bash
```
git branch -vv | grep ': gone]' | awk '{print $1}'
```
Combine both lists, removing duplicates. This catches:
- •Branches with commits directly in origin/main history (regular merge)
- •Branches whose remote tracking branch was deleted after merge (squash merge)
•
Handle dry-run mode:
- •
  If $ARGUMENTS contains --dry-run:
  - •Display the list of branches that would be pruned
  - •Exit without deleting
•
Display branches for confirmation:
- •
  If MERGED_BRANCHES is empty:
  code
  No merged branches to prune. All local branches have unmerged commits.
  Exit here.
- •
  Otherwise, display:
  code
  Found merged branches to prune: | Branch | Last Commit | |--------|-------------| | feature/auth | 3 days ago | | fix/login-bug | 1 week ago |
- •
  Use AskUserQuestion to confirm:
  - •"Delete all" - Delete all listed branches
  - •"Select branches" - Let user choose which to delete
  - •"Cancel" - Exit without deleting
•
Delete confirmed branches:

For branches detected via Method A (regular merge):
bash
```
git branch -d <branch-name>
```
For branches detected via Method B (squash merge / gone remote):
bash
```
git branch -D <branch-name>
```
Note: Method A branches use -d as a safety check. Method B branches require -D because their commits aren't in main's history (they were squashed). The "gone" remote is the indicator that the PR was merged.

•

Report results:

code

Pruned branches:
- feature/auth
- fix/login-bug

Kept branches:
- (none)

Remaining local branches: 3

Example Output

code

$ /git-prune-merged

Fetching latest from origin...

Found merged branches to prune:

| Branch | Last Commit |
|--------|-------------|
| docs/update-readme | 2 days ago |
| feature/add-auth | 1 week ago |
| fix/typo | 3 weeks ago |

? Delete these branches?
> Delete all
  Select branches
  Cancel

Pruned branches:
- docs/update-readme
- feature/add-auth
- fix/typo

Remaining local branches: 2 (main, feature/in-progress)

Important Notes

•Squash merge support: Detects branches whose remote was deleted after PR merge, even if squash-merged
•Safe deletion: Regular merges use -d; squash merges use -D (safe because remote deletion confirms merge)
•Protected branches: Never deletes main, master, or the current branch
•Remote cleanup: Run git fetch --prune separately to clean up stale remote-tracking references
•Worktrees: Branches in use by worktrees cannot be deleted; detach the worktree first

Known Edge Cases

Branch tracking `origin/main` instead of its own remote

Symptom: A squash-merged branch isn't detected even after git fetch --prune.

Cause: The branch was configured to track origin/main directly instead of origin/<branch-name>. When checking git branch -vv, it shows [origin/main: ahead X] instead of [origin/<branch-name>: gone].

Detection: Method B (git branch -vv | grep ': gone]') fails because origin/main still exists.

Resolution: These branches require manual identification. Check git branch -vv for branches showing [origin/main: ahead X] where the remote branch no longer exists:

bash

# Check if the branch's expected remote exists
git branch -r | grep "<branch-name>"
# If no output, the branch was likely merged and can be deleted with -D

Example: Branch feature/user-settings tracked origin/main instead of origin/feature/user-settings. After the PR was squash-merged and the remote deleted, it showed [origin/main: ahead 3] instead of : gone].