Merge Main into Current Branch

Merge the latest origin/main (or origin/master) into the current working branch, handle conflicts, and produce a summary report.

Your Task

Execute the following steps in order:

1. Pre-flight checks

1. Run git rev-parse --abbrev-ref HEAD to get the current branch name.
2. Run git status --porcelain to check for uncommitted changes.
   • If there are uncommitted changes, stop and warn the user. Ask if they want to stash or commit first. Do NOT proceed with a dirty working tree.
3. Determine the main branch: check if origin/main exists (git rev-parse --verify origin/main). If not, fall back to origin/master.

2. Fetch and merge

1. Run git fetch origin to get the latest remote state.
2. Run git log --oneline HEAD..{main-branch} --count (use git rev-list --count HEAD..{main-branch}) to see how many commits are incoming.
   • If 0 commits incoming, report "Already up to date" and stop.
3. Run git merge {main-branch} --no-edit.
4. Capture the merge output.

3. Handle conflicts

If the merge reports conflicts:

1. Run git diff --name-only --diff-filter=U to list conflicted files.
2. For each conflicted file: a. Read the file to see the conflict markers (<<<<<<<, =======, >>>>>>>). b. Analyze the conflict:
   • Theirs-only changes (our side is unchanged around the conflict): accept theirs.
   • Ours-only changes (their side is unchanged around the conflict): accept ours.
   • Both sides changed: Use your best judgment based on the code context. Prefer combining both changes when they don't overlap logically. If the conflict is complex or ambiguous, resolve it conservatively and flag it in the report. c. Edit the file to remove conflict markers and apply the resolution. d. Run git add {file} to mark it resolved.
3. After all conflicts are resolved, run git commit --no-edit to complete the merge.

4. Post-merge report

Generate a clear report with:

## Merge Report: {main-branch} → {current-branch}

### Summary
- **Incoming commits:** {count}
- **Conflicts:** {count} ({list of files, or "None"})
- **Status:** {Merged cleanly | Merged with conflict resolution}

### Incoming Commits
{list of commits from git log --oneline HEAD..origin/main BEFORE the merge, i.e., the commits that were brought in}

### Conflict Resolutions (if any)
For each resolved conflict:
- **{filename}**: {brief description of what conflicted and how it was resolved}

### Files Changed
{git diff --stat HEAD~1 summary showing files changed, insertions, deletions}

Important

• Never force-push or reset — this skill is purely additive (fetch + merge)
• If there are uncommitted changes, do not proceed — ask the user first
• If a conflict resolution is ambiguous, flag it clearly in the report so the user can review
• Always use --no-edit on merge/commit to avoid interactive editors
• After completion, do NOT push — leave that to the user