fix(react): guard processor cast and detach on cleanup

Two correctness fixes from PR review:

- Guard the `KrispNoiseFilterProcessor` cast in the returned `processor`
  value with a `name === 'livekit-noise-filter'` check. The
  unconditional cast assumed nothing else could attach a
  `TrackProcessor` to the track; if anything did, the hook handed
  consumers a value typed as a Krisp processor that wasn't one.

- Add a separate cleanup effect that detaches the processor we own
  when the underlying track changes or the hook unmounts. Tracks the
  attached processor + its track via refs so cleanup can verify
  identity (`track.getProcessor() === processor`) before calling
  `stopProcessor()` — avoids accidentally detaching a Krisp processor
  that some other module owns. Refs are populated only after
  `setProcessor` lands, so a cancelled mid-attach leaves them clear.
  Closes the gap where the track outlives the hook (caller-owned
  `trackRef` unmount or in-place swap to a different live track),
  while leaving the existing toggle-reuse path on `shouldEnable`
  unchanged.

Author: Topherhindman

.changeset/krisp-processor-per-track.md

@@ -2,4 +2,4 @@
 '@livekit/components-react': patch
 ---
 
-Fix `useKrispNoiseFilter` throwing `InvalidAccessError` on the second session when `Room.disconnect()` + reconnect republishes the microphone. The hook now treats `LocalAudioTrack.getProcessor()` as the source of truth and creates a fresh `KrispNoiseFilterProcessor` per track, avoiding reuse of a processor whose internal audio graph is bound to a now-closed `AudioContext`.
+Fix `useKrispNoiseFilter` throwing `InvalidAccessError` on the second session when `Room.disconnect()` + reconnect republishes the microphone. The hook now treats `LocalAudioTrack.getProcessor()` as the source of truth and creates a fresh `KrispNoiseFilterProcessor` per track, avoiding reuse of a processor whose internal audio graph is bound to a now-closed `AudioContext`. Also tightens the cancellation race when `setProcessor` resolves after the effect was cancelled, guards the returned `processor` against non-Krisp `TrackProcessor`s set by other modules, and detaches the processor on track change / unmount so a caller-owned `trackRef` is left in the state it started in.

packages/react/src/hooks/cloud/krisp/useKrispNoiseFilter.ts

@@ -48,6 +48,9 @@ export function useKrispNoiseFilter(options: useKrispNoiseFilterOptions = {}) {
     micPublication = options.trackRef.publication;
   }
 
+  const managedProcessorRef = React.useRef<KrispNoiseFilterProcessor | undefined>(undefined);
+  const managedProcessorTrackRef = React.useRef<LocalAudioTrack | undefined>(undefined);
+
   const setNoiseFilterEnabled = React.useCallback(async (enable: boolean) => {
     if (enable) {
       const { isKrispNoiseFilterSupported } = await import('@livekit/krisp-noise-filter');
@@ -105,12 +108,22 @@ export function useKrispNoiseFilter(options: useKrispNoiseFilterOptions = {}) {
         // component unmounted with the track still alive via a caller-owned
         // trackRef). Undo the attach so the track is left as we found it.
         if (cancelled) {
-          await track.stopProcessor();
+          if (track.getProcessor() === processor) {
+            await track.stopProcessor();
+          }
           return;
         }
+        managedProcessorRef.current = processor;
+        managedProcessorTrackRef.current = track;
         await processor.setEnabled(true);
         if (cancelled) {
-          await track.stopProcessor();
+          if (track.getProcessor() === processor) {
+            await track.stopProcessor();
+          }
+          if (managedProcessorRef.current === processor) {
+            managedProcessorRef.current = undefined;
+            managedProcessorTrackRef.current = undefined;
+          }
           return;
         }
         setIsNoiseFilterEnabled(true);
@@ -126,9 +139,29 @@ export function useKrispNoiseFilter(options: useKrispNoiseFilterOptions = {}) {
     };
   }, [shouldEnable, micPublication?.track, options.filterOptions]);
 
-  const processor =
+  React.useEffect(
+    () => () => {
+      const track = managedProcessorTrackRef.current;
+      const processor = managedProcessorRef.current;
+      if (!track || !processor) return;
+      if (track.getProcessor() === processor) {
+        track.stopProcessor().catch((e) => {
+          log.warn('Krisp hook: error detaching processor on cleanup', e);
+        });
+      }
+      managedProcessorRef.current = undefined;
+      managedProcessorTrackRef.current = undefined;
+    },
+    [micPublication?.track],
+  );
+
+  const trackProcessor =
     micPublication?.track instanceof LocalAudioTrack
-      ? (micPublication.track.getProcessor() as KrispNoiseFilterProcessor | undefined)
+      ? micPublication.track.getProcessor()
+      : undefined;
+  const processor =
+    trackProcessor?.name === 'livekit-noise-filter'
+      ? (trackProcessor as KrispNoiseFilterProcessor)
       : undefined;
 
   return {