Advanced Git & Collaboration

Professional collaboration with Git

You know how to use Git alone. Now learn to work in a team without stepping on other developers' toes.

🔀 Pull Requests (PRs)

A PR is a request to integrate your changes into the main branch. It's the heart of collaboration.

PR workflow

# 1. Create a branch for your feature
git checkout -b feature/new-functionality

# 2. Work and make commits
git add .
git commit -m "Add contact form"

# 3. Push your branch
git push -u origin feature/new-functionality

# 4. Create the PR on GitHub
gh pr create --fill
# Or go to GitHub and click "Compare & pull request"

Anatomy of a good PR

PR description example

## What does this PR do?
Adds contact form with validation.

## Why?
Users need to be able to contact us (#123)

## How to test?
1. Go to /contact
2. Fill out the form
3. Verify the email arrives

## Screenshots
[form image]

## Checklist
- [x] Tests pass
- [x] No console.logs
- [x] Responsive

⚔️ Merge Conflicts

They happen when two people modify the same lines. Don't panic.

What they look like

<<<<<<< HEAD
const message = "Main version";
=======
const message = "Your version";
>>>>>>> feature/my-branch

How to resolve them

# 1. Update your branch with main
git checkout feature/my-branch
git fetch origin
git merge origin/main
# Conflicts appear here

# 2. Open files with conflicts
# VS Code marks them in red/green

# 3. Decide which code to keep
# Remove the <<<<, ====, >>>> markers

# 4. Mark as resolved
git add file-with-conflict.js
git commit -m "Resolve conflicts with main"
git push

Tips to avoid conflicts

🔄 Rebase vs Merge

Two ways to integrate changes. Both valid, different uses.

Merge (preserves history)

git checkout main
git merge feature/my-branch

      A---B---C feature
     /         \
D---E---F---G---H main (merge commit)

Rebase (linear history)

git checkout feature/my-branch
git rebase main
git checkout main
git merge feature/my-branch  # Fast-forward

D---E---F---G---A'---B'---C' main

When to use each?

⚠️ Golden rule: Never rebase branches that others are using.

👥 Branching strategies

GitHub Flow (simple, recommended)

main ────●────●────●────●────●────
          \      /   \      /
           ●────●     ●────●
          feature    feature

• main always deployable
• Features in short-lived branches
• PRs for everything
• Deploy after merge

GitFlow (large enterprises)

main     ────────────●────────────●────
                    /            /
release  ──────●───●────────●───●────
              /   /        /   /
develop ●───●───●───●───●───●───●────
         \     /     \     /
          ●───●       ●───●
         feature     feature

• More complex, more control
• Branches: main, develop, feature, release, hotfix
• For planned releases

Trunk-Based (expert teams)

main ●───●───●───●───●───●───●───●
      \─/     \─/     \─/
      tiny    tiny    tiny

• Direct commits to main (or very small PRs)
• Feature flags for incomplete code
• Robust CI/CD required

🔍 Code Review

Reviewing others' code is as important as writing it.

As PR author

# Before requesting review
git diff main...HEAD  # Review your changes
npm test              # Ensure tests pass
npm run lint          # No style errors

As reviewer

How to give constructive feedback

❌ "This is wrong"
✅ "Consider using Optional Chaining here to avoid
    the error if user is undefined: user?.name"

❌ "I don't like it"
✅ "I'd prefer extracting this logic to a separate function
    to improve testability. What do you think?"

🏷️ Semantic Versioning

How to number releases: MAJOR.MINOR.PATCH

# Create a version tag
git tag -a v1.2.0 -m "Release 1.2.0: Add authentication"
git push origin v1.2.0

# List tags
git tag -l

# Create GitHub release
gh release create v1.2.0 --notes "Changelog here"

🛠️ Useful advanced commands

# Squash: Combine last 3 commits into one
git rebase -i HEAD~3
# Change "pick" to "squash" on commits to combine

# Cherry-pick: Bring a specific commit
git cherry-pick abc123

# Stash: Save changes temporarily
git stash
git stash pop

# Bisect: Find which commit introduced a bug
git bisect start
git bisect bad                 # Current commit has bug
git bisect good v1.0.0         # This version was fine
# Git guides you until finding the culprit

# Reflog: Recover "lost" commits
git reflog
git checkout HEAD@{2}

# Clean: Remove untracked files
git clean -fd

📋 Collaboration checklist

• Branch with descriptive name (feature/, fix/, hotfix/)
• Atomic commits with clear messages
• PR with complete description
• Tests pass in CI
• Code review approved
• No conflicts with main
• Squash or merge per team convention

🍳 Practice

→ Contribute to Open Source — Your first PR to a real project

Useful links

• 📖 GitHub Flow
• 📖 Conventional Commits
• 📖 Semantic Versioning
• 🎓 Learn Git Branching