name: git-mastery
user-invocable: false
description: |
Git workflow enforcement and best practices. Use when:
- Writing commit messages or reviewing commits
- Creating branches or choosing merge strategies
- Setting up CI/CD pipelines with git operations
- Resolving merge conflicts or rebasing
- Configuring repository settings or git hooks
- Optimizing large repository performance
Keywords: git, commit, branch, merge, rebase, PR, pull request, trunk-based,
conventional commits, atomic commits, git hooks, CODEOWNERS

Git Mastery

Enforce distributed-first, async-friendly git workflows with automated quality gates.

Commits: Atomic + Conventional

Every commit must be:
- Single logical change (use git add -p for selective staging)
- Complete (code + tests + docs together)
- Independently buildable and testable
- Describable without "and" in subject

Format: type(scope): subject (50 chars max)

feat(auth): add OAuth2 login flow
fix(api): handle null response in user endpoint
docs(readme): add deployment instructions
refactor(db): extract query builder

Types: feat, fix, docs, style, refactor, perf, test, build, ci, chore

BREAKING CHANGE: Add footer BREAKING CHANGE: description → triggers MAJOR version.

Branches: Short-Lived + Typed

Naming: type/issue-description (lowercase, hyphens, <60 chars)

feature/123-oauth-login
fix/456-null-pointer-api
hotfix/critical-auth-bypass

Rules:
- Max 3 days old (escalate if longer)
- Delete immediately after merge
- Rebase onto main daily: git pull --rebase origin main
- Never push directly to main

Merge Strategy (Algorithmic)

Main branch: fast-forward only (git config merge.ff only).

PR Workflow

1. CI passes before human review (lint, type-check, test, security)
2. CODEOWNERS auto-assigns reviewers
3. 1-2 approvals required
4. Squash fixup commits before merge
5. Branch auto-deleted on merge

Context-rich PRs: Include motivation, alternatives considered, areas of concern.

Performance (Large Repos)

Enable commit-graph:

git config core.commitGraph true
git config gc.writeCommitGraph true

Clone optimization:

git clone --filter=blob:none URL  # Partial clone
git sparse-checkout set src/      # Only needed paths

Large files (>10MB): Use Git LFS.

Anti-Patterns

• Mixed commits ("fix auth and update logging")
• Long-lived branches (>1 week without escalation)
• Manual merge strategy choice (use decision tree)
• Requiring sync coordination across timezones
• Large binary files in git history
• WIP/fix typo commits in main history

References

• conflict-resolution.md - Distributed async conflict patterns
• feature-flags.md - Flag-driven development for long features
• release-automation.md - Semantic versioning automation

Commit Conventions

See references/commit-conventions.md for detailed commit message standards including:
- Conventional commit format (type(scope): subject)
- Imperative mood rules
- Body and footer conventions
- Breaking change format