.gitignore Best Practices

This rule applies to files matching the patterns above.

# .gitignore Best Practices

## Rule
Every repository MUST have a .gitignore file configured BEFORE the first commit. Never track secrets, build outputs, or environment-specific files.

## Universal Ignores (Every Project)
```gitignore
# Environment & Secrets (CRITICAL)
.env
.env.*
!.env.example
*.pem
*.key
*.cert
credentials.*
secrets.*
**/service-account*.json

# OS Files
.DS_Store
Thumbs.db
Desktop.ini
*.swp
*.swo
*~

# IDE / Editor
.idea/
.vscode/
*.sublime-*
*.code-workspace

# Dependencies
node_modules/
vendor/
.venv/
__pycache__/
*.pyc

# Build Output
dist/
build/
out/
.next/
coverage/
*.min.js
*.min.css

# Logs
*.log
npm-debug.log*
yarn-error.log*

# Package Manager Locks (keep ONE, ignore others)
# If using npm: keep package-lock.json, ignore yarn.lock
# If using yarn: keep yarn.lock, ignore package-lock.json
```

## Language-Specific Additions

### Node.js / JavaScript
```gitignore
node_modules/
.npm
.eslintcache
.parcel-cache/
```

### Python
```gitignore
__pycache__/
*.py[cod]
*.egg-info/
.venv/
.mypy_cache/
.pytest_cache/
```

### Go
```gitignore
/bin/
/vendor/
*.exe
*.test
```

### Rust
```gitignore
/target/
Cargo.lock  # Only for libraries, keep for binaries
```

## Rules
1. **Create .gitignore BEFORE first commit** — always
2. **Never track .env files** with real credentials
3. **Provide .env.example** with placeholder values
4. **Use global gitignore** for OS/IDE files: `git config --global core.excludesfile ~/.gitignore_global`
5. **Check before committing**: `git status` to verify nothing unexpected is staged
6. **Use gitignore.io** to generate stack-specific templates

## If You Already Committed Something
```bash
# Remove file from tracking (keep local copy)
git rm --cached .env
echo ".env" >> .gitignore
git commit -m "chore: remove .env from tracking"

# Remove from entire history (if secrets were committed)
git filter-repo --invert-paths --path .env
```