Git Merge Into Main

---
name: git-merge-into-main
description: Use when a finished, reviewed branch is committed and needs to be merged into the default branch in a repo that integrates directly to `main` (not via pull request).
---

# Merge Into Main

Merges a finished branch into the default branch (e.g. `main`) by rebasing it on top, then fast-forwarding. For personal repos that integrate directly to `main` rather than through pull requests.

This skill does no reviewing and creates no commits.

## Process

1. **Check preconditions:** The branch must be committed with no unstaged files. It must also be reviewed by the user (not the same as a pull request review). Stop if either is missing.

2. **Rebase onto the default branch:** Find the default branch with `git default-branch`, then rebase the branch onto it. Always rebase, even for a trivial branch. Resolve any conflicts before continuing — do not `--skip` or force past them.

3. **Fast-forward and push:** Advance the default branch to the rebased branch with a fast-forward only (no merge commit), then push. If the default branch is checked out in another worktree, run the update from that worktree's directory — Git refuses to move a branch that is checked out elsewhere.

4. **Delete the merged branch:** Once the default branch has the commits, delete the branch with `git branch -d <branch>` (the `-d` refuses if it isn't fully merged, so it's a safety check). Run it from the default-branch worktree, never from inside the branch's own worktree.

   Git won't delete a branch that is checked out anywhere, so free it first. If the branch has a worktree that is no longer needed, remove it with `git worktree remove <branch-worktree>`. If something else owns that worktree's lifecycle — the `ls-agent:close-workspace` skill removes herdr worktrees itself — leave it in place and detach it instead with `git -C <branch-worktree> checkout --detach`.

   If the branch was pushed, also delete the remote with `git push origin --delete <branch>`.

```bash
default_branch=$(git default-branch)

git rebase "$default_branch"
git -C <default-branch-worktree> merge --ff-only <branch>
git -C <default-branch-worktree> push origin "$default_branch"

git -C <default-branch-worktree> worktree remove <branch-worktree>   # or checkout --detach, if the worktree stays
git -C <default-branch-worktree> branch -d <branch>
```

## Rationalizations

| Thought                                            | Reality                                                                     |
| -------------------------------------------------- | --------------------------------------------------------------------------- |
| "The branch is simple, I'll skip the rebase"       | Always rebase onto the default branch first, so the fast-forward is clean.  |
| "The rebase conflicted, I'll `--skip` or force"    | Resolve the conflict properly. Never discard commits to get past it.        |
| "I'll just merge it, a merge commit is fine"       | Fast-forward only. This skill keeps history linear.                         |
| "`main` won't move, I'll update it from here"      | If it's checked out in another worktree, update it from that worktree.      |
| "There are uncommitted changes, I'll merge anyway" | The branch must be committed and reviewed first. Stop.                      |
| "I'll remove the worktree while I'm in it"         | Run the removal from the default-branch worktree, or you delete your cwd.   |
| "Every merged branch's worktree should go"         | Leave the ones another skill owns. Detach those instead of removing them.   |
| "I'll leave the merged branch lying around"        | Delete it after the push; `-d` keeps it safe by refusing unmerged branches. |