Session Handoff

# Session Handoff — [date] [time]

## Status
- **Branch**: feature/xyz
- **Commits this session**: 3
- **Uncommitted changes**: 2 files modified
- **Tests**: passing / failing / not run

## What's Done
- [completed task 1]
- [completed task 2]

## What's In Progress
- [current task with context on where you stopped]
- [file:line that needs attention next]

## What's Pending
- [next task that hasn't been started]
- [blocked items with reason]

## Key Decisions Made
- [decision 1 and why]
- [decision 2 and why]

## Learnings Captured
- [Category] Rule (from this session)

## Files Touched
- `path/to/file1.ts` — [what changed]
- `path/to/file2.ts` — [what changed]

## Gotchas for Next Session
- [thing that tripped you up]
- [non-obvious behavior discovered]

## Resume Command
> Continue working on [branch]. [1-2 sentence context]. Next step: [specific action].

User: "Generate a handoff for this session"

Claude: Generating session handoff...

# Session Handoff — 2026-03-08 14:30

## Status
- **Branch**: feat/webhook-retry
- **Commits this session**: 2
  - a3f5c21 feat(webhooks): add retry logic with exponential backoff
  - b7d4e92 test(webhooks): add retry test cases
- **Uncommitted changes**: 1 file modified (src/config/webhooks.ts)
- **Tests**: 23 passed, 0 failed

## What's Done
✓ Implemented webhook retry logic with exponential backoff
✓ Added test coverage for retry scenarios
✓ Configured retry delays: 1s, 2s, 4s, 8s, 16s
✓ Added webhook status tracking (pending, sent, failed)

## What's In Progress
- Webhook configuration in src/config/webhooks.ts:15
  → Need to add retry count validation (max 10)
  → Need to add timeout configuration

## What's Pending
- Add webhook dashboard UI to show retry status
- Add webhook logs table to database
- Update API documentation
- Deploy to staging for testing

## Key Decisions Made

1. **Exponential backoff with jitter**
   Why: Prevents thundering herd when many webhooks fail simultaneously.
   Implemented fixed delays + random jitter (0-500ms).

2. **Max 5 retries**
   Why: Balance between delivery reliability and resource usage.
   After 5 failures (total ~31 seconds), mark as permanently failed.

3. **Store full request/response**
   Why: Debugging failed webhooks requires seeing exact payload.
   Trade-off: More storage, but worth it for observability.

## Learnings Captured

- [Testing] Mock setTimeout in retry tests to avoid slow tests (applied immediately)
- [Architecture] Store webhook attempts in separate table, not as JSON in main table

## Files Touched

- `src/lib/webhooks.ts` — Added retry logic with exponential backoff
- `src/lib/webhooks.test.ts` — Added 8 test cases for retry scenarios
- `src/config/webhooks.ts` — Started configuration (in progress)
- `src/types/webhook.ts` — Added WebhookAttempt type

## Gotchas for Next Session

- Don't forget to add database migration for webhook_attempts table
- The retry logic uses `setTimeout`, won't work in serverless (need queue)
- Webhook signatures need to be recalculated on retry (not implemented yet)

## Resume Command

> Continue working on feat/webhook-retry branch. Webhook retry logic implemented and tested. 
> Next step: Complete webhook configuration validation in src/config/webhooks.ts:15 (retry count and timeout).

Handoff saved to .claude/handoff-2026-03-08.md

User: "Create handoff, I need to step away"

Claude: Creating handoff...

# Session Handoff — 2026-03-08 16:45

## Status
- **Branch**: bugfix/auth-race-condition
- **Commits this session**: 0 (investigation only)
- **Uncommitted changes**: None
- **Tests**: Not applicable (investigation phase)

## What's Done
✓ Reproduced the auth race condition locally
✓ Identified root cause: token refresh and API call race
✓ Reviewed 3 potential solutions

## What's In Progress

- Deciding between solution approaches:
  
  **Option A: Request queue**
  - Queue requests during token refresh
  - Pros: Simple, no breaking changes
  - Cons: Adds complexity to auth middleware
  
  **Option B: Token lock**
  - Acquire lock before refresh, block other requests
  - Pros: Cleaner, prevents race at source
  - Cons: Could block legitimate requests
  
  **Option C: Optimistic refresh**
  - Refresh token proactively before expiry
  - Pros: Prevents race entirely
  - Cons: More API calls, complex timing

## What's Pending
- Choose solution approach (need team input)
- Implement chosen solution
- Add regression test
- Test in staging environment

## Key Decisions Made

1. **Root cause confirmed**
   Race condition in src/middleware/auth.ts:78-92.
   Two simultaneous requests both detect expired token,
   both try to refresh, second refresh fails with 401.

2. **Reproduction case**
   Created test in tests/auth/race-condition.test.ts that
   reliably reproduces the issue (previously intermittent).

## Learnings Captured

- [Testing] Use Promise.all() to trigger race conditions reliably in tests
- [Architecture] Token refresh should be a singleton operation, not per-request

## Files Touched

- `src/middleware/auth.ts` — Investigated token refresh logic (read-only)
- `tests/auth/race-condition.test.ts` — Created reproduction test case
- `docs/bugs/auth-race.md` — Documented investigation findings

## Gotchas for Next Session

- The race condition ONLY happens when token expires during a request
- Must test with very short token expiry (1 second) to reproduce
- Production logs show this happens ~5 times per day
- Affects all API endpoints, not just auth endpoints

## Resume Command

> Continue investigating auth race condition on bugfix/auth-race-condition branch.
> Root cause identified (concurrent token refresh). Three solution options documented.
> Next step: Choose solution approach (recommend Option A: request queue for simplicity).

Handoff saved to .claude/handoff-2026-03-08-2.md

User: "Handoff this session"

Claude: Generating handoff...

# Session Handoff — 2026-03-08 18:00

## Status
- **Branch**: feat/user-preferences
- **Commits this session**: 1
  - a3f5c21 feat(api): add user preferences endpoint (WIP)
- **Uncommitted changes**: 3 files modified
- **Tests**: ⚠️ 12 passed, 3 failing

## What's Done
✓ Created API endpoint: PATCH /api/users/:id/preferences
✓ Added database schema for user_preferences table
✓ Ran migration successfully

## What's In Progress

⚠️ **Incomplete work** — do not merge yet

- src/api/users/preferences.ts:45 — Validation logic incomplete
  → Email validation works
  → Theme validation added
  → TODO: Add notification preferences validation
  → TODO: Add timezone validation

- tests/api/preferences.test.ts — 3 tests failing
  → Test: "should reject invalid timezone" — timezone validation not implemented
  → Test: "should update notification settings" — field not in schema
  → Test: "should prevent XSS in bio field" — sanitization not added

## What's Pending

- Fix 3 failing tests (validation and sanitization)
- Add rate limiting to preferences endpoint
- Update API documentation
- Test with real data

## Key Decisions Made

1. **Store preferences as JSONB**
   Why: Flexible schema, can add new preferences without migrations.
   Trade-off: Less type safety, need runtime validation.

2. **Separate endpoint from user update**
   Why: Preferences change frequently, user profile rarely.
   Allows different rate limits and caching strategies.

## Learnings Captured

None this session (incomplete work).

## Files Touched

- `src/api/users/preferences.ts` — Created endpoint (incomplete validation)
- `src/types/preferences.ts` — Added types for preferences
- `tests/api/preferences.test.ts` — Added tests (3 failing)
- `migrations/007_user_preferences.sql` — Created and ran migration

## Gotchas for Next Session

⚠️ **Do not merge or deploy** — validation incomplete, tests failing

- Timezone validation needs third-party library (recommend: `@vvo/tzdb`)
- Notification preferences field not in database schema (need migration)
- Bio field needs XSS sanitization (recommend: `xss` package)
- Rate limiting not implemented (users could spam preferences updates)

## Resume Command

> Continue on feat/user-preferences branch. API endpoint created but validation incomplete.
> Next step: Fix 3 failing tests by completing validation logic in src/api/users/preferences.ts:45.
> Start with timezone validation using @vvo/tzdb library.

⚠️ Work in incomplete state. Prioritize finishing before starting new tasks.

Handoff saved to .claude/handoff-2026-03-08-3.md

## Session End

Before closing:
1. Run /wrap-up to check state
2. Generate /handoff document
3. Save to .claude/handoffs/[date].md

# Session Handoff — $DATE

## Branch: $BRANCH

## [Your custom sections here]

## Resume
> $RESUME_COMMAND

> Continue on feat/oauth branch. Google OAuth implemented, GitHub pending.
> Next step: Implement GitHub provider in src/auth/providers/github.ts.

> Keep working on auth stuff.