fix(sessions): stop chat-title regeneration on every view remount (#3315)

tatoalo · web-flow · commit f3332405ec47 · 2026-07-12T19:33:29.000-07:00
diff --git a/packages/core/src/sessions/chatTitle.test.ts b/packages/core/src/sessions/chatTitle.test.ts
@@ -103,6 +103,83 @@ describe("decideTitleGeneration", () => {
     });
     expect(decision.shouldGenerateFromTaskDescription).toBe(true);
   });
+
+  it.each([
+    {
+      name: "skips a catch-up fire when the title is locked and a summary exists",
+      promptCount: 1 + REGENERATE_INTERVAL,
+      lastGeneratedAtCount: 0,
+      initialDescriptionHandled: false,
+      titleLocked: true,
+      hasSummary: true,
+      expected: false,
+    },
+    {
+      name: "runs a catch-up fire when no summary exists yet",
+      promptCount: 1 + REGENERATE_INTERVAL,
+      lastGeneratedAtCount: 0,
+      initialDescriptionHandled: false,
+      titleLocked: true,
+      hasSummary: false,
+      expected: true,
+    },
+    {
+      name: "runs a catch-up fire when the title is not locked",
+      promptCount: 1 + REGENERATE_INTERVAL,
+      lastGeneratedAtCount: 0,
+      initialDescriptionHandled: false,
+      titleLocked: false,
+      hasSummary: true,
+      expected: true,
+    },
+    {
+      name: "still refreshes the summary at the interval while locked",
+      promptCount: 1 + REGENERATE_INTERVAL,
+      lastGeneratedAtCount: 1,
+      initialDescriptionHandled: false,
+      titleLocked: true,
+      hasSummary: true,
+      expected: true,
+    },
+    {
+      name: "still generates on the first prompt while locked",
+      promptCount: 1,
+      lastGeneratedAtCount: 0,
+      initialDescriptionHandled: false,
+      titleLocked: true,
+      hasSummary: false,
+      expected: true,
+    },
+    {
+      name: "treats a description-handled interval fire as organic while locked",
+      promptCount: REGENERATE_INTERVAL,
+      lastGeneratedAtCount: 0,
+      initialDescriptionHandled: true,
+      titleLocked: true,
+      hasSummary: true,
+      expected: true,
+    },
+  ])(
+    "$name",
+    ({
+      promptCount,
+      lastGeneratedAtCount,
+      initialDescriptionHandled,
+      titleLocked,
+      hasSummary,
+      expected,
+    }) => {
+      const decision = decideTitleGeneration({
+        promptCount,
+        lastGeneratedAtCount,
+        initialDescriptionHandled,
+        task: { title: "Custom", description: "d" },
+        isTitleLocked: () => titleLocked,
+        hasSummary,
+      });
+      expect(decision.shouldGenerateFromPrompts).toBe(expected);
+    },
+  );
 });
 
 describe("selectPromptsForTitle", () => {
diff --git a/packages/core/src/sessions/chatTitle.ts b/packages/core/src/sessions/chatTitle.ts
@@ -37,16 +37,36 @@ export function decideTitleGeneration(input: {
   lastGeneratedAtCount: number;
   initialDescriptionHandled: boolean;
   task: Pick<Task, "title" | "description">;
+  isTitleLocked?: () => boolean;
+  hasSummary?: boolean;
 }): TitleGenerationDecision {
-  const { promptCount, lastGeneratedAtCount, initialDescriptionHandled, task } =
-    input;
+  const {
+    promptCount,
+    lastGeneratedAtCount,
+    initialDescriptionHandled,
+    task,
+    isTitleLocked,
+    hasSummary = false,
+  } = input;
+
+  // A first fire on an already-long conversation whose title the user renamed
+  // and whose summary is already stored would produce nothing usable. Organic
+  // triggers (first prompt, every REGENERATE_INTERVAL prompts) still run while
+  // renamed so the summary stays current.
+  const skipStaleFire =
+    promptCount > 1 &&
+    lastGeneratedAtCount === 0 &&
+    !initialDescriptionHandled &&
+    hasSummary &&
+    (isTitleLocked?.() ?? false);
 
   const shouldGenerateFromPrompts =
-    (promptCount === 1 &&
+    !skipStaleFire &&
+    ((promptCount === 1 &&
       lastGeneratedAtCount === 0 &&
       !initialDescriptionHandled) ||
-    (promptCount > 1 &&
-      promptCount - lastGeneratedAtCount >= REGENERATE_INTERVAL);
+      (promptCount > 1 &&
+        promptCount - lastGeneratedAtCount >= REGENERATE_INTERVAL));
 
   const shouldGenerateFromTaskDescription =
     promptCount === 0 &&
diff --git a/packages/ui/src/features/sessions/hooks/useChatTitleGenerator.test.ts b/packages/ui/src/features/sessions/hooks/useChatTitleGenerator.test.ts
@@ -13,6 +13,9 @@ const mockSetQueriesData = vi.hoisted(() => vi.fn());
 const mockSetQueryData = vi.hoisted(() => vi.fn());
 const mockUpdateSessionTaskTitle = vi.hoisted(() => vi.fn());
 const mockPrompts = vi.hoisted(() => ({ value: [] as string[] }));
+const mockSessionSummary = vi.hoisted(() => ({
+  value: undefined as string | undefined,
+}));
 const mockSessionStoreSetters = vi.hoisted(() => ({ updateSession: vi.fn() }));
 const mockTitleAttachmentPaths = vi.hoisted(() => ({ value: [] as string[] }));
 const mockTitleAttachmentClear = vi.hoisted(() => vi.fn());
@@ -77,7 +80,14 @@ vi.mock("@posthog/ui/shell/titleAttachmentStore", () => ({
 vi.mock("@posthog/ui/features/sessions/sessionStore", () => {
   const state = {
     taskIdIndex: { "task-1": "run-1" },
-    sessions: { "run-1": { events: mockPrompts.value } },
+    get sessions() {
+      return {
+        "run-1": {
+          events: mockPrompts.value,
+          conversationSummary: mockSessionSummary.value,
+        },
+      };
+    },
   };
   const fn = Object.assign(
     (selector: (s: typeof state) => unknown) => selector(state),
@@ -89,6 +99,7 @@ vi.mock("@posthog/ui/features/sessions/sessionStore", () => {
   };
 });
 
+import { useTitleGenerationStore } from "@posthog/ui/features/sessions/titleGenerationStore";
 import { useChatTitleGenerator } from "./useChatTitleGenerator";
 
 const TASK_ID = "task-1";
@@ -113,11 +124,18 @@ function cacheTask(task: Task): void {
   mockGetQueriesData.mockReturnValue([[["tasks", "list"], [task]]]);
 }
 
+interface TitleAndSummaryResult {
+  title: string;
+  summary: string;
+}
+
 describe("useChatTitleGenerator", () => {
   beforeEach(() => {
     vi.clearAllMocks();
+    useTitleGenerationStore.setState({ byTaskId: {} });
     mockIsAuthenticated.value = true;
     mockPrompts.value = [];
+    mockSessionSummary.value = undefined;
     mockTitleAttachmentPaths.value = [];
     mockEnrichDescription.mockImplementation((desc: string) =>
       Promise.resolve(desc),
@@ -382,4 +400,89 @@ describe("useChatTitleGenerator", () => {
 
     expect(mockGenerateTitle).not.toHaveBeenCalled();
   });
+
+  it("does not regenerate when the chat view remounts after a generation", async () => {
+    mockGenerateTitle.mockResolvedValue({
+      title: "Fix login bug",
+      summary: "User is fixing a login issue",
+    });
+    mockPrompts.value = ["Fix the login bug"];
+
+    const first = renderHook(() =>
+      useChatTitleGenerator(createTask({ title: "Raw prompt title" })),
+    );
+    await waitFor(() => {
+      expect(mockGenerateTitle).toHaveBeenCalledTimes(1);
+    });
+    first.unmount();
+
+    renderHook(() =>
+      useChatTitleGenerator(createTask({ title: "Fix login bug" })),
+    );
+
+    await new Promise((resolve) => setTimeout(resolve, 0));
+    expect(mockGenerateTitle).toHaveBeenCalledTimes(1);
+  });
+
+  it("shares one in-flight guard across simultaneously mounted views", async () => {
+    let resolveGeneration!: (value: TitleAndSummaryResult) => void;
+    mockGenerateTitle.mockReturnValue(
+      new Promise((resolve) => {
+        resolveGeneration = resolve;
+      }),
+    );
+    mockPrompts.value = ["Fix the login bug"];
+
+    renderHook(() =>
+      useChatTitleGenerator(createTask({ title: "Raw prompt title" })),
+    );
+    renderHook(() =>
+      useChatTitleGenerator(createTask({ title: "Raw prompt title" })),
+    );
+
+    await waitFor(() => {
+      expect(mockGenerateTitle).toHaveBeenCalledTimes(1);
+    });
+
+    resolveGeneration({ title: "Fix login bug", summary: "" });
+    await new Promise((resolve) => setTimeout(resolve, 0));
+    expect(mockGenerateTitle).toHaveBeenCalledTimes(1);
+  });
+
+  it("skips catch-up generation when the title is locked and a summary exists", async () => {
+    const lockedTask = createTask({
+      title: "Custom auth title",
+      description: "fix auth",
+      title_manually_set: true,
+    });
+    cacheTask(lockedTask);
+    mockSessionSummary.value = "User wants to fix auth";
+    mockPrompts.value = Array.from({ length: 8 }, (_, i) => `prompt ${i}`);
+
+    renderHook(() => useChatTitleGenerator(lockedTask));
+
+    await new Promise((resolve) => setTimeout(resolve, 0));
+    expect(mockGenerateTitle).not.toHaveBeenCalled();
+  });
+
+  it("runs catch-up generation for a locked title when no summary exists yet", async () => {
+    const lockedTask = createTask({
+      title: "Custom auth title",
+      description: "fix auth",
+      title_manually_set: true,
+    });
+    cacheTask(lockedTask);
+    mockGenerateTitle.mockResolvedValue({
+      title: "Auto title",
+      summary: "User wants to fix auth",
+    });
+    mockPrompts.value = Array.from({ length: 8 }, (_, i) => `prompt ${i}`);
+
+    renderHook(() => useChatTitleGenerator(lockedTask));
+
+    await waitFor(() => {
+      expect(mockGenerateTitle).toHaveBeenCalledTimes(1);
+    });
+    expect(mockUpdateTask).not.toHaveBeenCalled();
+  });
 });
diff --git a/packages/ui/src/features/sessions/hooks/useChatTitleGenerator.ts b/packages/ui/src/features/sessions/hooks/useChatTitleGenerator.ts
@@ -18,11 +18,15 @@ import {
   sessionStoreSetters,
   useSessionStore,
 } from "@posthog/ui/features/sessions/sessionStore";
+import {
+  type TitleGenerationEntry,
+  titleGenerationStoreApi,
+} from "@posthog/ui/features/sessions/titleGenerationStore";
 import { taskKeys } from "@posthog/ui/features/tasks/taskKeys";
 import { logger } from "@posthog/ui/shell/logger";
 import { titleAttachmentStoreApi } from "@posthog/ui/shell/titleAttachmentStore";
 import { type QueryClient, useQueryClient } from "@tanstack/react-query";
-import { useEffect, useRef } from "react";
+import { useEffect } from "react";
 
 const log = logger.scope("chat-title-generator");
 
@@ -44,9 +48,6 @@ export function useChatTitleGenerator(task: Task): void {
   );
   const queryClient = useQueryClient();
   const client = useOptionalAuthenticatedClient();
-  const lastGeneratedAtCount = useRef(0);
-  const initialDescriptionHandled = useRef(false);
-  const isGenerating = useRef(false);
   const isAuthenticated = useAuthStateValue(
     (state) => state.status === "authenticated" && !!state.cloudRegion,
   );
@@ -61,30 +62,37 @@ export function useChatTitleGenerator(task: Task): void {
 
   useEffect(() => {
     if (!isAuthenticated) return;
-    if (isGenerating.current) return;
+
+    const bookkeeping = titleGenerationStoreApi.get(taskId);
+    if (bookkeeping.inFlight) return;
+
+    const state = useSessionStore.getState();
+    const taskRunId = state.taskIdIndex[taskId];
+    const session = taskRunId ? state.sessions[taskRunId] : undefined;
+    const isTitleLocked = () =>
+      isAutoTitleLocked(getCachedTask(queryClient, taskId) ?? task);
 
     const { shouldGenerateFromPrompts, shouldGenerateFromTaskDescription } =
       decideTitleGeneration({
         promptCount,
-        lastGeneratedAtCount: lastGeneratedAtCount.current,
-        initialDescriptionHandled: initialDescriptionHandled.current,
+        lastGeneratedAtCount: bookkeeping.lastGeneratedAtCount,
+        initialDescriptionHandled: bookkeeping.initialDescriptionHandled,
         task,
+        isTitleLocked,
+        hasSummary: !!session?.conversationSummary,
       });
 
     if (!shouldGenerateFromPrompts && !shouldGenerateFromTaskDescription) {
       return;
     }
 
-    isGenerating.current = true;
+    titleGenerationStoreApi.update(taskId, { inFlight: true });
 
-    const state = useSessionStore.getState();
-    const taskRunId = state.taskIdIndex[taskId];
-    const session = taskRunId ? state.sessions[taskRunId] : undefined;
     let rawContent = task.description;
 
     if (shouldGenerateFromPrompts) {
       if (!session?.events) {
-        isGenerating.current = false;
+        titleGenerationStoreApi.update(taskId, { inFlight: false });
         return;
       }
 
@@ -109,11 +117,8 @@ export function useChatTitleGenerator(task: Task): void {
           // up and try again with the file contents.
           titleAttachmentStoreApi.clear(taskId);
           const { title, summary } = result;
-          const titleLocked = isAutoTitleLocked(
-            getCachedTask(queryClient, taskId) ?? task,
-          );
 
-          if (title && titleLocked) {
+          if (title && isTitleLocked()) {
             log.debug("Skipping auto-title, user renamed task", { taskId });
           } else if (title) {
             if (client) {
@@ -157,13 +162,14 @@ export function useChatTitleGenerator(task: Task): void {
       } catch (error) {
         log.error("Failed to update task title", { taskId, error });
       } finally {
+        const patch: Partial<TitleGenerationEntry> = { inFlight: false };
         if (shouldGenerateFromPrompts) {
-          lastGeneratedAtCount.current = promptCount;
+          patch.lastGeneratedAtCount = promptCount;
         }
         if (shouldGenerateFromTaskDescription) {
-          initialDescriptionHandled.current = true;
+          patch.initialDescriptionHandled = true;
         }
-        isGenerating.current = false;
+        titleGenerationStoreApi.update(taskId, patch);
       }
     };
 
diff --git a/packages/ui/src/features/sessions/titleGenerationStore.ts b/packages/ui/src/features/sessions/titleGenerationStore.ts
