dtsong/git-merge-main

Scope Constraints

• Write operation — creates merge commits in the local repository
• Fetches from remote to update the target branch before merging
• Does not push to remote — use push skill for that
• Does not resolve conflicts — use conflicts skill if merge produces conflicts

Input Sanitization

• Target branch name: only alphanumeric characters, hyphens, underscores, and forward slashes. Reject spaces, .., shell metacharacters, or null bytes.
• Flags: only --no-commit accepted. Reject arbitrary strings.

/git-merge-main - Merge Main Into Feature Branch

Merge the latest main branch into your current feature branch to get updates.

Usage

/git-merge-main            # Merge main into current branch
/git-merge-main develop    # Merge develop instead of main
/git-merge-main --no-commit  # Merge but don't commit (for review)

When to Use

• Your feature branch is behind main
• You need changes from main to continue your work
• Before creating a PR (to ensure no conflicts)
• When main has critical fixes you need

Workflow

Step 1: Pre-flight Checks

# Get current branch
CURRENT=$(git branch --show-current)

# Cannot merge main into main
if [ "$CURRENT" = "main" ] || [ "$CURRENT" = "master" ]; then
    echo "Already on main branch. Nothing to merge."
    echo "Did you mean /git-pull?"
    exit 1
fi

# Check for uncommitted changes
if ! git diff --quiet || ! git diff --cached --quiet; then
    echo "You have uncommitted changes."
    echo "Options:"
    echo "  /git-stash - Stash changes first"
    echo "  /commit - Commit changes first"
    exit 1
fi

Step 2: Update Main

# Fetch latest main from remote
git fetch origin main:main 2>/dev/null || git fetch origin main

# Show what will be merged
echo "Commits from main to be merged:"
git log --oneline HEAD..origin/main | head -20

Step 3: Check for Potential Conflicts

# Preview merge (without committing)
if ! git merge --no-commit --no-ff origin/main 2>/dev/null; then
    echo "Merge will have conflicts."
    git merge --abort
    # Show conflicting files
    git diff --name-only --diff-filter=U
fi

Step 4: Execute Merge

# Perform the merge
git merge origin/main --no-ff -m "Merge main into $CURRENT"

# Or without commit for review
git merge origin/main --no-commit --no-ff

Step 5: Report Result

Show merge result and any follow-up needed.

Output Format

Clean Merge

Merging main into feat/dark-mode...

Merged 5 commits from main:
  abc1234 Fix security vulnerability
  def5678 Update dependencies
  ghi9012 Improve performance
  jkl3456 Add new API endpoint
  mno7890 Documentation updates

Files updated:
  package.json
  src/api/endpoints.ts
  src/utils/security.ts
  README.md

Merge complete! Your branch now includes all changes from main.

Next steps:
  - Test your feature still works
  - /git-push to update remote branch

Already Up To Date

Branch feat/dark-mode is already up to date with main.

No merge needed.

Merge Conflicts

Merge conflicts detected!

Conflicting files:
  - src/components/Header.tsx (both modified)
  - src/styles/theme.css (both modified)

To resolve:
  /git-conflicts         # Get help resolving

After resolving:
  git add <resolved-files>
  git commit

To abort:
  /git-abort

No-Commit Preview

When using --no-commit:

Merge staged but not committed.

Changes from main:
  M src/api/endpoints.ts
  M package.json
  A src/utils/newHelper.ts

Review the changes, then:
  git commit -m "Merge main into feat/dark-mode"

Or abort:
  git merge --abort

Best Practices

1. Always fetch first: Ensures you have the latest main
2. Check status before: No uncommitted changes
3. Test after merge: Ensure your feature still works
4. Commit message: Use descriptive merge message
5. Consider rebase: For cleaner history, use /git-rebase instead

Merge vs Rebase

| Merge | Rebase | |-------|--------| | Preserves complete history | Creates linear history | | Shows when integration happened | Looks like sequential development | | Better for shared branches | Better for personal branches | | Non-destructive | Rewrites commit history |

Integration

• Use /git-sync first to see what's on main
• Use /git-rebase for cleaner history (alternative)
• Use /git-conflicts if merge has conflicts
• Use /git-abort to cancel a failed merge