app/src/hooks/useNotes.test.ts

@@ -163,4 +163,47 @@ describe("useNotes", () => {
     // listNotes should be called again after the save
     expect(listNotes).toHaveBeenCalledTimes(callCountBefore + 1);
   });
+
+  it("does not overwrite the new project's notes when a stale save resolves", async () => {
+    const { result, rerender } = renderHook(
+      ({ projectId }: { projectId: string }) => useNotes(projectId),
+      { initialProps: { projectId: "p1" } },
+    );
+    await waitFor(() => expect(result.current.loading).toBe(false));
+    expect(result.current.notes[0].id).toBe("n1");
+
+    // Start a save for p1 that hangs
+    let resolveSave: ((note: Note) => void) | undefined;
+    saveNote.mockImplementationOnce(
+      () =>
+        new Promise((resolve) => {
+          resolveSave = resolve;
+        }),
+    );
+
+    let savePromise: Promise<boolean> | undefined;
+    await act(async () => {
+      savePromise = result.current.saveNote(note({ id: "n1" }));
+    });
+
+    // Switch to p2 while the save is in flight
+    listNotes.mockResolvedValueOnce([note({ id: "n2", title: "Project 2 Note" })]);
+    rerender({ projectId: "p2" });
+    await waitFor(() => expect(result.current.loading).toBe(false));
+
+    // Now p2's note should be displayed
+    expect(result.current.notes).toHaveLength(1);
+    expect(result.current.notes[0].id).toBe("n2");
+
+    // Resolve the stale p1 save
+    listNotes.mockResolvedValueOnce([note({ id: "n1", body: "edited" })]);
+    await act(async () => {
+      resolveSave?.(note({ id: "n1", body: "edited" }));
+      await savePromise;
+    });
+
+    // p2's note should still be displayed, not p1's
+    expect(result.current.notes).toHaveLength(1);
+    expect(result.current.notes[0].id).toBe("n2");
+  });
 });

app/src/hooks/useNotes.ts

@@ -34,6 +34,8 @@ export function useNotes(projectId: string) {
   const [saveState, setSaveState] = useState<SaveState>({ status: "idle", error: null });
   const pushToast = useAppState((s) => s.pushToast);
   const resetTimer = useRef<ReturnType<typeof setTimeout> | null>(null);
+  const currentProjectId = useRef(projectId);
+  currentProjectId.current = projectId;
 
   useEffect(() => {
     if (!projectId) {
@@ -94,7 +96,12 @@ export function useNotes(projectId: string) {
         // what a reload would show.
         try {
           const reloaded = await commands.listNotes(projectId);
-          setNotes(reloaded);
+          // Guard against a stale callback: if the project changed while the save was in
+          // flight, don't overwrite the new project's list with the old one. The save itself
+          // still succeeded, so succeeded() still fires; only the list replacement is skipped.
+          if (currentProjectId.current === projectId) {
+            setNotes(reloaded);
+          }
         } catch {
           // Keep the save reported as successful (it was) and leave the existing list alone
           // rather than clearing it if the re-read fails.
@@ -126,7 +133,12 @@ export function useNotes(projectId: string) {
     async (noteId: string) => {
       try {
         await commands.deleteNote(projectId, noteId);
-        setNotes((current) => current.filter((n) => n.id !== noteId));
+        // Guard against a stale callback: if the project changed while the delete was in
+        // flight, don't modify the list. Note ids are UUIDs so a stale filter cannot match
+        // another project's note, but applying the same guard for consistency.
+        if (currentProjectId.current === projectId) {
+          setNotes((current) => current.filter((n) => n.id !== noteId));
+        }
         return true;
       } catch (e) {
         pushToast({ kind: "error", message: "Could not delete note", detail: String(e) });