From a79a6aaa513f422ce33e777a03b0da3c1c57bd0a Mon Sep 17 00:00:00 2001
From: chanx <1243304602@qq.com>
Date: Thu, 13 Aug 2026 16:15:24 +0800
Subject: [PATCH] fix(web): abort the stream when its in-flight question is
 deleted (#18214)

---
 web/src/pages/next-chats/chat-stream/store.ts | 29 +++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/web/src/pages/next-chats/chat-stream/store.ts b/web/src/pages/next-chats/chat-stream/store.ts
index 0ecb403ed2..6420e6d07e 100644
--- a/web/src/pages/next-chats/chat-stream/store.ts
+++ b/web/src/pages/next-chats/chat-stream/store.ts
@@ -240,6 +240,12 @@ export const useChatStreamStore = create<ChatStreamState>()(
           (state) => {
             const previous = state.sessions[conversationId];
             if (!previous) return state;
+            // A session that is no longer streaming has no trailing placeholder
+            // to fill in. The reader's final flush runs before endStream, so
+            // this also guards the case where the in-flight question (and its
+            // placeholder) were just deleted: without it, the flush would slice
+            // off whatever message is now last.
+            if (!previous.isStreaming) return state;
             return {
               sessions: {
                 ...state.sessions,
@@ -304,6 +310,20 @@ export const useChatStreamStore = create<ChatStreamState>()(
 
       removeMessageById: (conversationId, messageId) => {
         if (!conversationId) return;
+
+        // Deleting the question that is currently being answered has to stop
+        // that answer too: the stream lives at module level, so it would
+        // otherwise keep producing tokens for a question that is gone. The
+        // question and its assistant placeholder are appended as a pair (and
+        // share an id), so the in-flight question sits second to last.
+        const session = get().sessions[conversationId];
+        const removingStreamedQuestion = Boolean(
+          session?.isStreaming && session.messages.at(-2)?.id === messageId,
+        );
+        if (removingStreamedQuestion) {
+          session?.abortController?.abort();
+        }
+
         set(
           (state) => {
             const previous = state.sessions[conversationId];
@@ -314,6 +334,15 @@ export const useChatStreamStore = create<ChatStreamState>()(
                 [conversationId]: {
                   ...previous,
                   messages: previous.messages.filter((x) => x.id !== messageId),
+                  // Close the session right here instead of waiting for the
+                  // reader's endStream, so the abort's trailing flush can't
+                  // write the deleted answer back into the list.
+                  isStreaming: removingStreamedQuestion
+                    ? false
+                    : previous.isStreaming,
+                  abortController: removingStreamedQuestion
+                    ? undefined
+                    : previous.abortController,
                 },
               },
             };