---
phase: 16-attachment-finalization
plan: 02
subsystem: ui
tags: [uat, testing, bug-fixes, deduplication, unread-count, session-attachments]

# Dependency graph
requires:
  - phase: 16-01
    provides: Error handling and toast notifications
  - phase: 15-01
    provides: Real-time synchronization
  - phase: 14-02
    provides: Attachment display in chat
provides:
  - Validated all 26 requirements for v1.2 Session Attachments
  - Fixed attachment message deduplication bug
  - Fixed unread count persistence across page reloads
  - Complete UAT sign-off for milestone completion
affects: [v1.2-milestone-completion, future-chat-features]

# Tech tracking
tech-stack:
  added: []
  patterns:
    - "Triple-location deduplication for attachment messages"
    - "Eager chat history fetch on session join"
    - "lastReadAt-based unread count calculation"

key-files:
  created:
    - .planning/phases/16-attachment-finalization/16-UAT-CHECKLIST.md
  modified:
    - jam-ui/src/store/features/sessionChatSlice.js
    - jam-ui/src/components/client/JKSessionScreen.js

key-decisions:
  - "Deduplication must check attachmentId in all three message-adding code paths"
  - "Fetch chat history on session join (not chat window open) for unread persistence"
  - "Calculate unread count from lastReadAt timestamp in fetchChatHistory.fulfilled"

patterns-established:
  - "Deduplication by attachmentId: Check in addMessageFromWebSocket, fetchChatHistory.fulfilled, AND uploadAttachment.fulfilled"
  - "Eager fetch pattern: Load data on screen mount, not on modal open"
  - "Unread calculation: Compare message timestamps with localStorage-persisted lastReadAt"

# Metrics
duration: ~30min
completed: 2026-02-07
---

# Phase 16 Plan 02: UAT & Final Verification Summary

**User Acceptance Testing for v1.2 Session Attachments with bug discovery and fixes**

## Performance

- **Duration:** ~30 min
- **Started:** 2026-02-07
- **Completed:** 2026-02-07
- **Tasks:** 2 (UAT checklist creation + human verification)
- **Bugs found:** 2 (both fixed)
- **Files modified:** 2

## Accomplishments

- Created comprehensive UAT checklist with 74 test cases covering all 26 requirements
- Conducted manual UAT testing of attachment upload and display
- Discovered and fixed attachment message deduplication bug
- Discovered and fixed unread count persistence bug
- All requirements validated and working correctly

## Bugs Discovered During UAT

### Bug 1: Attachment Message Deduplication

**Symptom:** Attachment messages appeared twice in chat window for the uploading client.

**Root Cause:** Race condition - WebSocket message could arrive before upload API returned. The `uploadAttachment.fulfilled` handler only checked for duplicates by message ID format (`attachment-${notation.id}`), but WebSocket messages have a different ID format (the chat message ID).

**Fix:** Added `attachmentId` deduplication check in all three message-adding code paths:
1. `addMessageFromWebSocket` - checks by attachmentId ✓
2. `fetchChatHistory.fulfilled` - checks by attachmentId ✓
3. `uploadAttachment.fulfilled` - checks by attachmentId ✓ (added)

**Commits:** `c1ed8470a`, `20d025943`

### Bug 2: Unread Count Not Persisting Across Page Reload

**Symptom:** Unread badge on chat button disappeared after page reload, even with unread messages.

**Root Cause:**
1. `unreadCounts` was reset to `{}` on page reload
2. `fetchChatHistory` was only called when chat window opened
3. By that time, `openChatWindow` already reset the count to 0

**Fix:**
1. Added `fetchChatHistory` dispatch when session joins (in JKSessionScreen.js)
2. Added unread count calculation in `fetchChatHistory.fulfilled` based on `lastReadAt` timestamp

**Commit:** `7110e7cdf`

## Task Commits

1. **Task 1: Create UAT Checklist** - `08283e24e` (docs)
2. **Task 2: Human Verification** - Manual testing with bug fixes:
   - `c1ed8470a` - Initial deduplication fix attempt
   - `20d025943` - Complete deduplication fix in uploadAttachment.fulfilled
   - `7110e7cdf` - Unread count persistence fix

## Files Created/Modified

- `.planning/phases/16-attachment-finalization/16-UAT-CHECKLIST.md` - 74 test cases (NEW)
- `jam-ui/src/store/features/sessionChatSlice.js` - Deduplication and unread count fixes
- `jam-ui/src/components/client/JKSessionScreen.js` - Eager chat history fetch on session join

## Decisions Made

**1. Triple-location deduplication for attachment messages**
- **Rationale:** Message deduplication must be bulletproof across all code paths
- **Implementation:** Check by `attachmentId` in addMessageFromWebSocket, fetchChatHistory.fulfilled, AND uploadAttachment.fulfilled
- **Learning:** Race conditions require defensive programming in ALL entry points

**2. Eager chat history fetch on session join**
- **Rationale:** Unread badge must show before chat window opens
- **Implementation:** Dispatch fetchChatHistory in useEffect when hasJoined becomes true
- **Benefit:** Consistent UX - badge always shows correct count

**3. lastReadAt-based unread calculation**
- **Rationale:** localStorage persists across reloads, provides reliable baseline
- **Implementation:** Compare message timestamps with lastReadAt in fetchChatHistory.fulfilled
- **Edge case:** If no lastReadAt, all messages are considered unread

## Deviations from Plan

- **Added bug fix work:** Plan assumed all code was complete, but UAT revealed 2 bugs requiring fixes
- **Extended scope:** Beyond verification to actual implementation fixes

## Issues Encountered

Both bugs were resolved during the UAT session:
1. Deduplication - Required understanding the race condition between WebSocket and REST API
2. Unread persistence - Required understanding the fetch timing and state reset sequence

## Next Steps

**Phase 16 Complete** - Ready for milestone completion:
- All 26 requirements validated
- Error handling complete (REQ-5.1 through REQ-5.5)
- Real-time synchronization working
- File upload and display working
- Unread tracking working

**v1.2 Session Attachments Milestone Ready for Sign-off**

Run `/gsd:complete-milestone` to archive v1.2 and prepare for next milestone.

---
*Phase: 16-attachment-finalization*
*Plan: 02*
*Completed: 2026-02-07*
