fix: guard combined diff notes async state (#3558)

src/renderer/src/components/editor/CombinedDiffViewer.tsx

@@ -181,6 +181,7 @@ export default function CombinedDiffViewer({
   const [clearNotesDialogOpen, setClearNotesDialogOpen] = useState(false)
   const [isClearingNotes, setIsClearingNotes] = useState(false)
   const [notesCopied, setNotesCopied] = useState(false)
+  const mountedRef = useRef(true)
   // Why: clipboard IPC can resolve after the combined diff unmounts; skip
   // copied feedback instead of starting a reset timer on a stale viewer.
   const notesCopyMountedRef = useRef(false)
@@ -203,6 +204,13 @@ export default function CombinedDiffViewer({
     scrollContainerRef.current = node
     notesCopyMountedRef.current = node !== null
   }, [])
+
+  useEffect(() => {
+    mountedRef.current = true
+    return () => {
+      mountedRef.current = false
+    }
+  }, [])
   const loadSchedulerRef = useRef(
     createCombinedDiffLoadScheduler({
       loadSection: (index) => loadSectionRef.current(index)
@@ -906,13 +914,18 @@ export default function CombinedDiffViewer({
     setIsClearingNotes(true)
     try {
       const ok = await clearDiffComments(file.worktreeId)
+      if (!mountedRef.current) {
+        return
+      }
       if (ok) {
         setClearNotesDialogOpen(false)
       } else {
         toast.error('Failed to clear notes.')
       }
     } finally {
-      setIsClearingNotes(false)
+      if (mountedRef.current) {
+        setIsClearingNotes(false)
+      }
     }
   }, [clearDiffComments, diffCommentCount, file.worktreeId, isClearingNotes])