PR Writing Skill

Guidelines for writing pull request descriptions that help reviewers understand and approve changes quickly.

PR Title Format

#<issue-number> <type>: <concise description>

Always prefix the PR title with the GitHub issue number to enable easy cross-referencing.

Types

Good Titles

#42 feat: Add user registration endpoint
#187 fix: Prevent duplicate form submissions
#23 refactor: Extract authentication logic into service
#91 docs: Add API documentation for user endpoints

Bad Titles

Update code                    # Too vague, no issue number
Fixed the bug                  # Which bug? No issue number
WIP                           # Not ready for review
feat: Add login               # Missing issue number prefix

PR Body Structure

## Summary
[1-3 sentences explaining WHAT changed and WHY]

Closes #<issue-number>

## Changes
- [Specific change 1]
- [Specific change 2]
- [Specific change 3]

## Testing
- [ ] Unit tests added/updated
- [ ] Integration tests pass
- [ ] Manual testing completed

## Screenshots (if UI changes)
[Before/after screenshots or GIFs]

## Notes for Reviewers
[Optional: Areas to focus on, known limitations, questions]

Writing the Summary

Focus on WHY, not just WHAT

Bad:

Added a new function called validateEmail and updated the user model.

Good:

Adds email validation to prevent invalid emails from being stored, which was causing delivery failures in the notification system.

Be Specific About Impact

Bad:

Fixed authentication bug.

Good:

Fixes session timeout not being respected when "Remember Me" is checked, which was causing users to be logged out after 30 minutes regardless of their preference.

Keep It Scannable

Reviewers often skim. Front-load the important information:

Bad:

After investigating the issue that was reported last week about the dashboard loading slowly, I discovered that we were making redundant API calls. This PR addresses that by implementing caching.

Good:

Reduces dashboard load time by 60% by caching API responses. The redundant calls were causing 3-second delays on each page load.

Describing Changes

Be Specific and Organized

Group related changes:

## Changes

### API
- Add `POST /api/users/register` endpoint
- Add request validation middleware
- Add rate limiting (10 requests/minute)

### Database
- Add `email_verified` column to users table
- Add index on `email` column

### Tests
- Add unit tests for registration validation
- Add integration tests for registration flow

Explain Non-Obvious Changes

## Changes
- Increase connection pool size from 10 to 25
  - Load testing showed connection exhaustion under peak traffic
- Add retry logic to external API calls
  - The payment provider has occasional 503s that resolve on retry

Linking to Issues

Always link the related issue:

Closes #123

Or for partial work:

Related to #123
Part of #123

Highlighting Review Focus

Help reviewers prioritize their attention:

## Notes for Reviewers

**Please focus on:**
- The caching invalidation logic in `src/cache/manager.ts` - I'm unsure if this handles all edge cases
- The error handling in the new endpoint

**You can skim:**
- The test files follow existing patterns
- The migration is straightforward

Screenshots and Visuals

For UI changes, always include:

## Screenshots

### Before
[screenshot]

### After
[screenshot]

For complex flows, use GIFs or numbered screenshots:

## User Flow

1. User clicks "Register"
   [screenshot 1]

2. Validation errors shown inline
   [screenshot 2]

3. Success state with redirect
   [screenshot 3]

Breaking Changes

Clearly call out breaking changes:

## ⚠️ Breaking Changes

- `getUserById()` now returns `null` instead of throwing when user not found
- The `/api/v1/users` endpoint is deprecated, use `/api/v2/users`

### Migration Guide
1. Update all `try/catch` blocks around `getUserById()` to null checks
2. Update API clients to use v2 endpoint

Draft PRs

Use draft PRs for:

• Work in progress needing early feedback
• Architectural decisions to discuss
• Proof of concepts

## 🚧 Draft PR

This is a draft to get early feedback on the approach.

**Questions:**
1. Should we use Redis or in-memory caching?
2. Is this the right place for this logic?

**Not yet complete:**
- [ ] Error handling
- [ ] Tests
- [ ] Documentation

Checklist Before Submitting

Before marking ready for review:

• Title follows #<issue> type: description format
• Summary explains what AND why
• Issue is linked with Closes #X
• Changes are listed specifically
• Tests are included and passing
• Screenshots added for UI changes
• Breaking changes are highlighted
• Self-reviewed the diff for obvious issues
• Branch is synced with main (no merge conflicts)

PR Size Guidelines

If a PR is large, explain why:

## Note on PR Size

This PR is larger than usual because it includes a database migration
that requires updating all affected queries atomically. Splitting would
leave the codebase in a broken state.