fix(01-review): sweep #1 stopRecording nulls mediaStream first to prevent rotation race

src/offscreen/recorder.ts

@@ -359,16 +359,40 @@ function onUserStoppedSharing(): void {
 }
 
 function stopRecording(): void {
-  // Отменяем будущую ротацию, чтобы rotateSegment не дёрнул stop() на
-  // уже остановленном рекордере.
+  // Sweep #1 fix: race between rotateSegment / onSegmentStopped and a
+  // STOP_RECORDING that does NOT null the mediaStream. The previous
+  // implementation cleared the rotation timer and called .stop(), which
+  // triggers onSegmentStopped async; onSegmentStopped then unconditionally
+  // calls startNewSegment() whenever `mediaStream !== null`. Result: after
+  // a manual STOP_RECORDING, a new segment would spawn anyway and the
+  // recorder kept rolling silently. The fix mirrors onUserStoppedSharing:
+  // null the mediaStream FIRST so onSegmentStopped's gate sees the stopped
+  // state, then stop the recorder and release the tracks. This also fixes
+  // the secondary issue of leaked MediaStreamTracks (the picker indicator
+  // would have stayed up until the operator manually clicked "Stop
+  // sharing" in Chrome's UI).
   if (rotationTimerId !== null) {
     clearTimeout(rotationTimerId);
     rotationTimerId = null;
   }
+  // Capture stream before nulling so we can release its tracks.
+  const streamToStop = mediaStream;
+  mediaStream = null;
   if (videoRecorder !== null && videoRecorder.state !== 'inactive') {
-    videoRecorder.stop();
+    try {
+      videoRecorder.stop();
+    } catch (err) {
+      logger.warn('stop() during stopRecording failed:', err);
+    }
     logger.log('Recording stopped manually');
   }
+  if (streamToStop !== null) {
+    streamToStop.getTracks().forEach((t) => t.stop());
+  }
+  // Note: we do NOT call resetBuffer() here — the operator may want to
+  // STOP and then SAVE the buffered footage. resetBuffer happens on
+  // onUserStoppedSharing (operator dismissed Chrome's sharing indicator)
+  // and at the start of the next startRecording().
 }
 
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