nickgallick Git Mastery
Commit Discipline
Atomic Commits
One logical change per commit. Not "Add validation, fix typo, update styles" — three separate commits.
Conventional Commit Format
<type>(<scope>): <description>
feat(arena): add weight class verification after challenge
fix(elo): prevent race condition in concurrent ELO updates
refactor(entries): extract submission validation to service layer
docs(api): add cursor pagination examples to API docs
test(judging): add consensus validation edge case tests
chore(deps): update @supabase/ssr to 0.5.2
Types: feat, fix, refactor, docs, test, chore, perf, ci, style
Rules
- Imperative mood: "Add validation" not "Added validation"
- Under 72 characters for subject line
- Body explains WHY, not WHAT (the diff shows WHAT)
- Never commit:
.env,node_modules,.DS_Store, build output, large binaries
PR Size
- Under 400 lines changed. If larger, split.
- One feature or fix per PR. Not "feature + refactor + dependency update."
PR Review Patterns (What Forge Checks)
- Read the diff, not just the files — context of changes matters
- Check what was REMOVED as carefully as what was added
- Read test changes first — they tell you what the PR is supposed to do
- Check for missing changes — migration without type update? Route without test?
- Check commit messages — do they tell a coherent story?
Git Archaeology for Debugging
# Who changed this line and why?
git blame path/to/file.ts
# Recent history of a specific file
git log --oneline -10 -- src/features/entries/service.ts
# Binary search for when a bug was introduced
git bisect start
git bisect bad # current commit is broken
git bisect good v1.2.0 # this tag was working
# Git checks out middle commit → you test → mark good/bad → repeat
# See all changes on a branch vs main
git diff main...feature/arena-judging
# Find deleted code
git log --diff-filter=D -- path/to/deleted-file.ts
Recovery Patterns
| Situation | Command |
|---|---|
| Undo last commit (keep changes) | git reset --soft HEAD~1 |
| Revert a merged PR | git revert -m 1 <merge-commit> |
| Recover deleted branch | git reflog → find commit → git checkout -b branch <hash> |
| Fix last commit message | git commit --amend |
| Unstage a file | git restore --staged path/to/file |
| Discard local changes | git restore path/to/file |
| Save WIP without committing | git stash → later: git stash pop |
Sources
- Conventional Commits specification
- Airbnb git conventions
- Pro Git book (Scott Chacon)
Changelog
- 2026-03-21: Initial skill — git mastery