From 533b90a3a4ebc39dadd70b90819ee76d1b142f76 Mon Sep 17 00:00:00 2001
From: Kyle Carberry <kyle@coder.com>
Date: Sat, 28 Feb 2026 21:38:16 -0500
Subject: [PATCH] fix: resolve chat title update race conditions and improve
 resilience (#22450)
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## Problem

Chat titles sometimes don't update in the UI. The generated AI title
gets stuck as the fallback (first 6 words of the message) even though
the backend successfully generates a proper title.

## Root Causes

### 1. Cancelable context used during cleanup DB read (P0)
In `processChat`, the deferred cleanup re-reads the chat from the DB to
pick up the AI-generated title for the `status_change` pubsub event. But
it used the cancelable `ctx` instead of `cleanupCtx`:

```go
// Before — ctx may already be canceled here
if freshChat, readErr := p.db.GetChatByID(ctx, chat.ID); readErr == nil {
```

When the context is canceled, the DB read fails silently and the
`status_change` event carries the stale fallback title.

### 2. Title goroutine not tracked by inflight WaitGroup (P2)
The `maybeGenerateChatTitle` goroutine was fire-and-forget — not tracked
by `p.inflight`. During graceful shutdown, the server could exit before
the goroutine completes its DB write or pubsub publish.

### 3. No recovery when watchChats() WebSocket misses events
The frontend relies entirely on the `watchChats()` SSE connection for
title updates. If the connection drops or misses events, titles never
recover — the only fix was a full page reload.

## Fixes

1. **Use `cleanupCtx`** for the `GetChatByID` call and logger in the
deferred cleanup block.
2. **Track the title goroutine** with `p.inflight.Add(1)` / `defer
p.inflight.Done()` so shutdown waits for it.
3. **Invalidate chats query** on WebSocket open/close/error events so
missed updates are recovered via refetch. Also enable
`refetchOnWindowFocus` for the chats query.

Co-authored-by: Coder <coder@users.noreply.github.com>
---
 coderd/chatd/chatd.go                    | 10 +++++++---
 site/src/api/queries/chats.ts            |  1 +
 site/src/pages/AgentsPage/AgentsPage.tsx |  9 +++++++++
 3 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/coderd/chatd/chatd.go b/coderd/chatd/chatd.go
index 3476e68bb5..06fa5b7f8d 100644
--- a/coderd/chatd/chatd.go
+++ b/coderd/chatd/chatd.go
@@ -1741,10 +1741,10 @@ func (p *Server) processChat(ctx context.Context, chat database.Chat) {
 		// changes made during processing (e.g. AI-generated titles
 		// from maybeGenerateChatTitle). The local `chat` variable
 		// is a value copy and won't reflect updates made in runChat.
-		if freshChat, readErr := p.db.GetChatByID(ctx, chat.ID); readErr == nil {
+		if freshChat, readErr := p.db.GetChatByID(cleanupCtx, chat.ID); readErr == nil {
 			chat = freshChat
 		} else {
-			logger.Warn(ctx, "failed to re-read chat for status event",
+			logger.Warn(cleanupCtx, "failed to re-read chat for status event",
 				slog.F("chat_id", chat.ID), slog.Error(readErr))
 		}
 		chat.Status = status
@@ -1816,7 +1816,11 @@ func (p *Server) runChat(
 	// Fire title generation asynchronously so it doesn't block the
 	// chat response. It uses a detached context so it can finish
 	// even after the chat processing context is canceled.
-	go p.maybeGenerateChatTitle(context.WithoutCancel(ctx), chat, messages, model, logger)
+	p.inflight.Add(1)
+	go func() {
+		defer p.inflight.Done()
+		p.maybeGenerateChatTitle(context.WithoutCancel(ctx), chat, messages, model, logger)
+	}()
 
 	prompt, err := chatprompt.ConvertMessages(messages)
 	if err != nil {
diff --git a/site/src/api/queries/chats.ts b/site/src/api/queries/chats.ts
index 1065204723..43f6ade2db 100644
--- a/site/src/api/queries/chats.ts
+++ b/site/src/api/queries/chats.ts
@@ -8,6 +8,7 @@ export const chatKey = (chatId: string) => ["chats", chatId] as const;
 export const chats = () => ({
 	queryKey: chatsKey,
 	queryFn: () => API.getChats(),
+	refetchOnWindowFocus: true as const,
 });
 
 export const chat = (chatId: string) => ({
diff --git a/site/src/pages/AgentsPage/AgentsPage.tsx b/site/src/pages/AgentsPage/AgentsPage.tsx
index 4d27543e59..efe3fcd764 100644
--- a/site/src/pages/AgentsPage/AgentsPage.tsx
+++ b/site/src/pages/AgentsPage/AgentsPage.tsx
@@ -267,6 +267,15 @@ const AgentsPage: FC = () => {
 
 	useEffect(() => {
 		const ws = watchChats();
+		ws.addEventListener("open", () => {
+			void queryClient.invalidateQueries({ queryKey: chatsKey });
+		});
+		ws.addEventListener("close", () => {
+			void queryClient.invalidateQueries({ queryKey: chatsKey });
+		});
+		ws.addEventListener("error", () => {
+			void queryClient.invalidateQueries({ queryKey: chatsKey });
+		});
 		ws.addEventListener("message", (event) => {
 			const sse = event.parsedMessage;
 			if (sse?.type !== "data" || !sse.data) {