Git Version Control: Branches, Merge Conflicts & Workflow Best Practices

This comprehensive Git tutorial covers everything from basic commands to advanced workflow strategies.

Git Fundamentals

Basic Git Commands

# Initialize a repository
git init

# Clone an existing repository
git clone <repository-url>

# Check status
git status

# Add files to staging area
git add <filename>
git add .

# Commit changes
git commit -m "Descriptive commit message"

# Push changes to remote
git push origin main

# Pull changes from remote
git pull origin main

Understanding Git States

• Working Directory: Your local files
• Staging Area: Files ready to commit
• Local Repository: Your committed changes
• Remote Repository: Shared repository (GitHub/GitLab)

Branching Strategy

Creating and Managing Branches

# Create new branch
git branch feature-new-feature

# Switch to branch
git checkout feature-new-feature

# Create and switch branch in one command
git checkout -b feature-new-feature

# List all branches
git branch -a

# Delete branch (local)
git branch -d feature-new-feature

# Delete branch (remote)
git push origin --delete feature-new-feature

Merging Branches

# Switch to target branch
git checkout main

# Merge feature branch
git merge feature-new-feature

# Merge with commit message
git merge feature-new-feature --no-ff -m "Merge feature: Add new functionality"

# Abort merge
git merge --abort

Handling Merge Conflicts

Understanding Merge Conflicts

Merge conflicts occur when Git cannot automatically resolve differences between branches.

Resolving Conflicts

# Start merge
git merge feature-branch

# Git shows conflicts
# <<<<<<< HEAD
# Your changes
# =======
# Their changes
# >>>>>>> feature-branch

# Edit files to resolve conflicts
# Remove conflict markers and keep desired content

# Mark as resolved
git add <resolved-file>

# Continue merge
git commit

Conflict Resolution Tools

# Use merge tool
git mergetool

# Check for conflicts
git diff --name-only --diff-filter=U

# Show conflict details
git diff

Professional Git Workflows

Git Flow Workflow

# Initialize Git Flow
git flow init

# Start feature
git flow feature start new-feature

# Finish feature
git flow feature finish new-feature

# Start release
git flow release start v1.0.0

# Finish release
git flow release finish v1.0.0

# Start hotfix
git flow hotfix start critical-bug-fix

# Finish hotfix
git flow hotfix finish critical-bug-fix

GitHub Flow (Simplified)

# 1. Create branch
git checkout -b feature/user-authentication

# 2. Make changes and commit
git add .
git commit -m "Add user authentication"

# 3. Push branch
git push origin feature/user-authentication

# 4. Create Pull Request on GitHub

# 5. Review and merge via GitHub interface

# 6. Update local main
git checkout main
git pull origin main

Advanced Git Commands

Rebase vs Merge

# Rebase feature branch onto main
git checkout feature-branch
git rebase main

# Interactive rebase
git rebase -i HEAD~3

# Rebase with conflicts
git rebase --continue
git rebase --abort

Cherry-pick

# Copy specific commit to current branch
git cherry-pick <commit-hash>

# Cherry-pick without committing
git cherry-pick --no-commit <commit-hash>

Stashing Changes

# Stash current changes
git stash

# Stash with message
git stash save "Work in progress on feature X"

# List stashes
git stash list

# Apply stash
git stash apply

# Apply and remove stash
git stash pop

# Drop specific stash
git stash drop stash@{1}

Best Practices

Commit Guidelines

1. Atomic commits: One logical change per commit
2. Descriptive messages: Use present tense, be specific
3. Conventional commits: Use standard format (feat:, fix:, docs:, etc.)

# Good commit messages
git commit -m "feat: Add user authentication system"
git commit -m "fix: Resolve memory leak in data processing"
git commit -m "docs: Update API documentation"

Branch Naming Conventions

# Feature branches
feature/user-login
feature/payment-integration

# Bugfix branches
bugfix/memory-leak
bugfix/validation-error

# Hotfix branches
hotfix/critical-security-patch
hotfix/database-connection

# Release branches
release/v1.2.0

Repository Organization

# Use .gitignore
echo "node_modules/" > .gitignore
echo "*.log" >> .gitignore
echo ".env" >> .gitignore

# Keep repository clean
git clean -fd

# Use tags for releases
git tag -a v1.0.0 -m "Release version 1.0.0"
git push origin v1.0.0

Troubleshooting Common Issues

Undo Changes

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

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

# Undo specific commit
git revert <commit-hash>

# Reset to remote state
git reset --hard origin/main

Recover Lost Commits

# Find lost commits
git reflog

# Restore lost commit
git checkout <commit-hash>
git checkout -b recovery-branch

Large File Handling

# Check repository size
git count-objects -vH

# Find large files
git rev-list --objects --all | git cat-file --batch-check='%(objecttype) %(objectname) %(objectsize) %(rest)' | sed -n 's/^blob //p' | sort -n

# Use Git LFS for large files
git lfs track "*.zip"
git add .gitattributes
git add large-file.zip
git commit -m "Add large file with LFS"

Integration with Development Tools

Git Hooks

# Install pre-commit hook
cp .git/hooks/pre-commit.sample .git/hooks/pre-commit

# Example pre-commit hook
#!/bin/sh
# Run tests before commit
npm test
# Check code style
npm run lint

IDE Integration

• VS Code: Built-in Git integration
• IntelliJ IDEA: Advanced Git support
• Sublime Text: Git packages available

Security Considerations

1. Never commit sensitive data: passwords, API keys, tokens
2. Use environment variables: For configuration
3. Signed commits: Verify author identity
4. Access control: Manage repository permissions

# Configure Git user
git config --global user.name "Your Name"
git config --global user.email "your.email@example.com"

# Sign commits with GPG
git config --global commit.gpgsign true
git config --global gpg.program gpg