Managing Git

Best practices for version control, branching strategies, and collaborative development.

When to Use This Skill

Setting up branching strategies
Writing commit messages
Handling merges and conflicts
Managing releases
Code review workflows
Maintaining clean history

Branching Strategies

Git Flow

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

| Branch | Purpose | Branches From | Merges Into | |--------|---------|---------------|-------------| | main | Production code | - | - | | develop | Integration | main | release | | feature/* | New features | develop | develop | | release/* | Release prep | develop | main, develop | | hotfix/* | Production fixes | main | main, develop |

Use when: Scheduled releases, multiple versions supported

GitHub Flow

main ─────●─────●─────●─────●─────●────▶
           \   /       \   /       \   /
feature     ●─●         ●─●         ●─●
            PR          PR          PR

| Branch | Purpose | |--------|---------| | main | Always deployable | | feature/* | All changes (features, fixes) |

Use when: Continuous deployment, simple workflow

Trunk-Based Development

main ─────●──●──●──●──●──●──●──●──●──●────▶
           │  │  │  │  │  │  │  │  │  │
          ●   ●  ●  ●  ●  ●  ●  ●  ●  ●
          Small, frequent commits (often direct to main)

Use when: High trust teams, strong CI/CD, frequent deploys

Commit Message Conventions

Conventional Commits

<type>(<scope>): <subject>

<body>

<footer>

Types

| Type | Description | Example | |------|-------------|---------| | feat | New feature | feat(auth): add OAuth2 login | | fix | Bug fix | fix(api): handle null response | | docs | Documentation | docs(readme): update setup steps | | style | Formatting | style: fix indentation | | refactor | Code restructuring | refactor(db): simplify query builder | | test | Adding tests | test(user): add registration tests | | chore | Maintenance | chore(deps): update lodash | | perf | Performance | perf(search): add index on email | | ci | CI/CD changes | ci: add Node 18 to matrix |

Good vs Bad Commits

BAD:
  - "fix"
  - "update code"
  - "WIP"
  - "changes"
  - "asdfasdf"

GOOD:
  - "fix(auth): prevent session timeout on idle"
  - "feat(cart): add quantity validation"
  - "refactor(api): extract common error handling"

Commit Body Guidelines

fix(payment): prevent double charge on retry

The payment gateway timeout was causing the retry logic to submit
duplicate charges. Added idempotency key to prevent double-processing.

Closes #1234

First line: 50 chars max, imperative mood
Body: Wrap at 72 chars, explain why, not what
Footer: Reference issues, breaking changes

Branch Naming Conventions

Pattern

<type>/<ticket>-<short-description>

Examples

| Type | Example | |------|---------| | Feature | feature/AUTH-123-add-oauth-login | | Bugfix | fix/CART-456-quantity-validation | | Hotfix | hotfix/PROD-789-memory-leak | | Chore | chore/update-dependencies | | Docs | docs/api-documentation |

Branch Rules

Lowercase with hyphens
Include ticket number when available
Keep short but descriptive
Delete after merge

Git Workflow Commands

Daily Workflow

# Start new feature
git checkout main
git pull origin main
git checkout -b feature/AUTH-123-add-login

# Work on feature
git add -p                    # Stage hunks interactively
git commit -m "feat(auth): add login form"

# Keep up to date
git fetch origin
git rebase origin/main        # Preferred: clean history
# OR
git merge origin/main         # Alternative: preserves context

# Push and create PR
git push -u origin feature/AUTH-123-add-login

Useful Commands

| Command | Purpose | |---------|---------| | git stash | Save uncommitted changes temporarily | | git stash pop | Restore stashed changes | | git commit --amend | Modify last commit | | git rebase -i HEAD~3 | Interactive rebase (squash, reorder) | | git cherry-pick <sha> | Apply specific commit | | git bisect | Binary search for bug introduction | | git reflog | View all HEAD movements (recovery) |

Cleanup Commands

# Delete merged branches locally
git branch --merged | grep -v main | xargs git branch -d

# Prune remote tracking branches
git fetch --prune

# Clean untracked files (careful!)
git clean -fd

Handling Conflicts

Conflict Resolution Flow

1. Identify conflicts
   git status

2. Open conflicted files
   <<<<<<< HEAD
   your changes
   =======
   their changes
   >>>>>>> feature-branch

3. Resolve (keep one, combine, or rewrite)

4. Mark resolved
   git add <resolved-file>

5. Continue
   git rebase --continue   # if rebasing
   git commit              # if merging

Prevention Strategies

Small, frequent merges - Reduce conflict scope
Communication - Coordinate on shared files
Feature flags - Reduce long-lived branches
Clear ownership - Minimize overlapping work

Pull Request Best Practices

PR Checklist

[ ] Branch is up to date with main
[ ] Tests pass locally
[ ] Linting passes
[ ] Self-review completed
[ ] Documentation updated
[ ] Ticket/issue linked
[ ] Screenshots for UI changes

PR Size Guidelines

| Size | Lines Changed | Review Time | Recommendation | |------|---------------|-------------|----------------| | Small | 1-100 | 15 min | Ideal | | Medium | 100-400 | 30-60 min | Acceptable | | Large | 400+ | 1+ hour | Split if possible |

PR Description Template

## Summary
Brief description of changes

## Changes
- Added X
- Modified Y
- Removed Z

## Testing
- [ ] Unit tests added
- [ ] Manual testing done

## Screenshots (if applicable)
[Before/After images]

## Related Issues
Closes #123

Release Management

Semantic Versioning

MAJOR.MINOR.PATCH
  │     │     │
  │     │     └── Bug fixes (backward compatible)
  │     └── New features (backward compatible)
  └── Breaking changes

Release Process

# Create release branch
git checkout -b release/v1.2.0 develop

# Bump version, update changelog
# ... make changes ...

# Merge to main and tag
git checkout main
git merge release/v1.2.0
git tag -a v1.2.0 -m "Release v1.2.0"
git push origin main --tags

# Merge back to develop
git checkout develop
git merge release/v1.2.0

Changelog Format

# Changelog

## [1.2.0] - 2024-01-15
### Added
- OAuth2 authentication support

### Changed
- Improved error messages

### Fixed
- Memory leak in cache handler

### Deprecated
- Old authentication method (use OAuth2)

### Removed
- Legacy API v1 endpoints

Git Hooks

Common Hooks

| Hook | Timing | Use Case | |------|--------|----------| | pre-commit | Before commit | Linting, formatting | | commit-msg | After message | Validate message format | | pre-push | Before push | Run tests | | post-merge | After merge | Install dependencies |

Example pre-commit

#!/bin/sh
# .git/hooks/pre-commit

# Run linter
npm run lint
if [ $? -ne 0 ]; then
  echo "Linting failed. Please fix errors."
  exit 1
fi

# Run tests
npm test
if [ $? -ne 0 ]; then
  echo "Tests failed. Please fix before committing."
  exit 1
fi

Using Husky (Node.js)

// package.json
{
  "husky": {
    "hooks": {
      "pre-commit": "lint-staged",
      "commit-msg": "commitlint -E HUSKY_GIT_PARAMS"
    }
  }
}

Troubleshooting

Common Issues

| Problem | Solution | |---------|----------| | Accidental commit to main | git reset HEAD~1 (before push) | | Wrong branch | git stash, switch, git stash pop | | Need to undo merge | git revert -m 1 <merge-commit> | | Lost commits | git reflog to find, git cherry-pick | | Large file committed | git filter-branch or BFG Repo-Cleaner |

Recovery Commands

# Undo last commit (keep changes)
git reset --soft HEAD~1

# Undo last commit (discard changes)
git reset --hard HEAD~1

# Recover deleted branch
git reflog
git checkout -b recovered-branch <sha>

# Undo a pushed commit (safe)
git revert <sha>

Anti-Patterns to Avoid

Force pushing to shared branches - Breaks others' history
Giant commits - Hard to review, hard to bisect
Vague commit messages - "fix" tells nothing
Long-lived branches - Merge conflict hell
Committing generated files - Bloats repo, causes conflicts
Committing secrets - Security risk (even after removal)
Rebasing public history - Breaks collaborators
Ignoring CI failures - Broken windows effect

Quick Reference

BRANCHES:
  main       → Production (protected)
  develop    → Integration (Git Flow)
  feature/*  → New work
  fix/*      → Bug fixes
  hotfix/*   → Production emergencies

COMMITS:
  feat(scope): add feature
  fix(scope): fix bug
  docs(scope): update docs
  refactor(scope): restructure code

DAILY FLOW:
  git checkout -b feature/ticket-desc
  git add -p && git commit
  git rebase origin/main
  git push -u origin feature/ticket-desc

VERSIONING:
  MAJOR.MINOR.PATCH
  Breaking.Feature.Bugfix