Installing Git Hooks

Installing Git Hooks

Purpose

Enforce quality checks automatically:

• Pre-commit: format, lint, typecheck
• Pre-push: test

Hooks call justfile commands (DRY).

Quick Setup

cat > .git/hooks/pre-commit << 'EOF'
#!/bin/bash
set -e
echo "Running pre-commit checks..."
just format
just lint
just typecheck
echo "✅ Pre-commit checks passed"
EOF
chmod +x .git/hooks/pre-commit

cat > .git/hooks/pre-push << 'EOF'
#!/bin/bash
set -e
echo "Running pre-push checks..."
just test
echo "✅ Pre-push checks passed"
EOF
chmod +x .git/hooks/pre-push

Justfile Integration

# Install git hooks
hooks:
    @echo "Installing git hooks..."
    @cat > .git/hooks/pre-commit << 'EOF'\n#!/bin/bash\nset -e\necho "Running pre-commit checks..."\njust format\njust lint\njust typecheck\necho "✅ Pre-commit checks passed"\nEOF
    @chmod +x .git/hooks/pre-commit
    @cat > .git/hooks/pre-push << 'EOF'\n#!/bin/bash\nset -e\necho "Running pre-push checks..."\njust test\necho "✅ Pre-push checks passed"\nEOF
    @chmod +x .git/hooks/pre-push
    @echo "✅ Git hooks installed"

hooks-remove:
    rm -f .git/hooks/pre-commit .git/hooks/pre-push
    @echo "✅ Git hooks removed"

Pre-commit Framework

For teams or complex setups:

.pre-commit-config.yaml:

repos:
  - repo: local
    hooks:
      - id: format
        name: Format code
        entry: just format
        language: system
        pass_filenames: false

      - id: lint
        name: Lint code
        entry: just lint
        language: system
        pass_filenames: false

      - id: typecheck
        name: Type check
        entry: just typecheck
        language: system
        pass_filenames: false

      - id: test
        name: Run tests
        entry: just test
        language: system
        pass_filenames: false
        stages: [push]

Install:

pip install pre-commit
pre-commit install
pre-commit install --hook-type pre-push

Python with venv

#!/bin/bash
set -e
source .venv/bin/activate
just format
just lint
just typecheck

Polyglot Projects

#!/bin/bash
set -e

if git diff --cached --name-only | grep -q "^api/"; then
    cd api && just format && just lint && just typecheck
fi

if git diff --cached --name-only | grep -q "^web/"; then
    cd web && just format && just lint && just typecheck
fi

Best Practices

• Fast: Format/lint/typecheck in seconds
• Fail fast: Use set -e to exit on first error
• Match CI: Hooks should match CI checks
• Document: Include setup in README/onboarding

Skipping (Use Sparingly)

git commit --no-verify -m "message"  # Skip pre-commit
git push --no-verify                 # Skip pre-push

Troubleshooting

Hook not running:

ls -la .git/hooks/pre-commit
chmod +x .git/hooks/pre-commit
head -1 .git/hooks/pre-commit  # Verify shebang

Just not found:

#!/bin/bash
export PATH="$HOME/.cargo/bin:$PATH"
set -e
just format

Venv issues:

#!/bin/bash
set -e
source .venv/bin/activate
just format