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Fix race condition blocking multi-turn chat conversations #13

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Fix race condition blocking multi-turn chat conversations #13

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Copilot AI commented Jan 29, 2026 •
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Problem

Dashboard chat accepted the first message but silently ignored follow-ups, breaking multi-turn conversations. Root cause: sendMessage checked React state to guard against duplicate sends, but state lagged storage updates by up to 400ms (the polling interval).

Changes

Query storage directly instead of stale React state:

// Before: Race condition when messages sent < 400ms after completion
const threadFromStorage = threads.find(t => t.id === targetThreadId);

// After: Always check source of truth
const threadFromStorage = await threadStore.getById(targetThreadId);

Removed threads dependency from useCallback since we no longer read from React state for the streaming check.

Technical Details

The flow that caused the bug:

  1. Message completes → executeChatResponse writes isStreaming: false to storage
  2. User sends follow-up before polling refreshes React state
  3. Check sees stale isStreaming: true → message silently dropped

Storage queries bypass the stale state issue entirely while maintaining the duplicate-send protection.

Original prompt

This section details on the original issue you should resolve

<issue_title>Bug: Dashboard chat only works for single turn (follow-ups don't trigger AI)</issue_title>
<issue_description>## Description
During livestream testing, discovered that the chat experience on the dashboard only works for the initial message. Follow-up messages don't trigger the AI to respond.

Steps to Reproduce

  1. Navigate to dashboard
  2. Send initial chat message
  3. AI responds successfully
  4. Send follow-up message
  5. AI does not respond

Expected Behavior

Chat should support multi-turn conversations where follow-up messages trigger AI responses.

Actual Behavior

Only the first message gets a response. Subsequent messages are ignored.

Impact

  • Users cannot have ongoing conversations
  • Limits chat usefulness to single Q&A exchanges</issue_description>

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Copilot AI changed the title [WIP] Fix dashboard chat to support multi-turn conversations Fix race condition blocking multi-turn chat conversations Jan 29, 2026
Copilot AI requested a review from chrisreddington January 29, 2026 13:35
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github-actions bot commented Jan 29, 2026 •
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Dependency Review

✅ No vulnerabilities or license issues or OpenSSF Scorecard issues found.

Scanned Files

None

Copilot AI and others added 3 commits January 29, 2026 14:49
@chrisreddington
Initial plan
aed44f5
@chrisreddington
Fix: Check actual storage state instead of stale React state
8630a4b 
The bug was in `sendMessage` function which checked React state to see if a thread was streaming, but React state could be stale after a message completed. This caused rapid follow-up messages to be blocked.

Fixed by:
- Query threadStore.getById() directly instead of using threads from React state
- Remove threads from useCallback dependency array (no longer needed)

Co-authored-by: chrisreddington <791642+chrisreddington@users.noreply.github.com>
@chrisreddington
Fix: Track expected message count to properly poll for multi-turn res…
7963368 
…ponses

The previous fix to check storage directly still had a race condition for
multi-turn conversations. The cleanup effect that removes threads from
the pending list was incorrectly triggered when a thread already had
assistant messages from previous turns.

Root cause: The old logic checked for ANY completed assistant message,
but for multi-turn chat, the thread already has completed responses
from earlier turns. When sending a follow-up, the cleanup effect would
immediately remove the thread from pending (since hasCompletedResponse
was true), stopping the polling before the new response arrived.

Fix: Track the expected message count when starting a job:
- Store Map<threadId, expectedMessageCount> instead of Set<threadId>
- Only remove from pending once thread.messages.length >= expected count
- This correctly handles multi-turn: after each message, we expect
  current count + 2 (user + assistant)

Verified with Playwright: Can now send multiple follow-up messages
and each receives a proper AI response.
@chrisreddington chrisreddington force-pushed the copilot/fix-dashboard-chat-multi-turn branch from ddfcc56 to 7963368 Compare January 29, 2026 14:49
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Bug: Dashboard chat only works for single turn (follow-ups don't trigger AI)

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@chrisreddington