43. Merging Pull Requests

Merging Pull Requests

Learn the different ways to merge PRs and when to use each method.

Merge Options

GitHub offers three merge methods:

1. Create a Merge Commit

Characteristics:

• Preserves complete history
• Creates merge commit (M)
• Shows branch existed

When to use:

• Want full history
• Team prefers seeing branch structure

2. Squash and Merge

Characteristics:

• Combines all commits into one
• Clean, linear history
• Loses individual commit details

When to use:

• Feature had many WIP commits
• Want clean history
• Individual commits aren't important

3. Rebase and Merge

Characteristics:

• Linear history
• Preserves individual commits
• Rewrites commit hashes

When to use:

• Want linear history
• Each commit is meaningful
• No merge commits needed

How to Merge

Basic Merge

1. Open PR
2. Verify all checks pass (green ✓)
3. Click Merge pull request
4. Choose merge method
5. Click Confirm merge
6. Click Delete branch (optional but recommended)

Merge Requirements

Configure in Settings → Branches:

Handling Merge Conflicts

When Conflicts Occur

GitHub shows: "This branch has conflicts that must be resolved"

Resolve on GitHub

1. Click Resolve conflicts
2. Edit the file in the web editor
3. Remove conflict markers
4. Click Mark as resolved
5. Click Commit merge

Resolve Locally

1# Update your branch
2git checkout feature-branch
3git pull origin main
4
5# Resolve conflicts in your editor
6# Edit files, remove conflict markers
7
8# Stage resolved files
9git add .
10
11# Complete the merge
12git commit -m "Resolve merge conflicts with main"
13
14# Push updated branch
15git push origin feature-branch

After Merging

Delete Branch

1# On GitHub: Click "Delete branch" button
2
3# Locally:
4git checkout main
5git pull origin main
6git branch -d feature-branch
7git fetch --prune

Verify Merge

1. Check main branch has the changes
2. Verify deployment (if auto-deploy enabled)
3. Confirm issue is closed (if linked)

Merge Best Practices

1. Always Review Before Merging

Even if you're the only reviewer:

• Check the diff
• Ensure tests pass
• Verify it works

2. Use Consistent Merge Strategy

Pick a strategy and stick with it:

3. Delete Branches After Merge

Keep repository clean:

1# Configure auto-delete on GitHub
2Settings → General → Automatically delete head branches ☑

4. Write Good Merge Commit Messages

For squash merges:

5. Don't Force Merge

If checks fail, fix them:

Reverting a Merge

If something goes wrong:

Via GitHub

1. Go to PR (even after merged)
2. Click Revert
3. Creates new PR to undo changes
4. Merge the revert PR

Via Command Line

1git checkout main
2git revert -m 1 <merge-commit-hash>
3git push origin main

Summary

Choose based on your team's preferences and project needs!