fix(homekit): only hang up when the last HomeKit session ends

homekit.js

@@ -558,8 +558,14 @@ function _stopSession(sessionID, hangUp) {
   if (s.ffOut) killFfmpeg(s.ffOut);
   if (s.sdpPath) removeReturnAudioSdp(s.sdpPath);
 
+  // Only the last session ending means the user is finished. HomeKit runs up
+  // to cameraStreamCount sessions at once, and moving between the room view's
+  // camera tile and the full camera view starts a second one, so a STOP here
+  // routinely arrives while another session is still streaming. Hanging up on
+  // it kills a live call: seen on 2026-09-12, where session ac5c8c21 stopping
+  // ended the call under session d332e46a three seconds into the stream.
   const activeCall = getActiveCall();
-  if (hangUp && activeCall) {
+  if (hangUp && activeCall && activeSessions.size === 0) {
     scheduleHangUp(activeCall.callSid, sessionID);
   }
 }
@@ -920,8 +926,12 @@ module.exports = {
   shutdown,
   // Exported for tests/homekit-hangup-grace.test.cjs. Reaching the deferred
   // hangup through the streaming delegate would mean standing up a full SRTP
-  // session, which tests nothing about the timer.
+  // session, which tests nothing about the timer. _stopSession and the session
+  // map go with them: driving only scheduleHangUp tests when the timer fires
+  // but not whether it should have been set, which is where the live bug was.
   scheduleHangUp,
   cancelPendingHangUp,
   deferPendingHangUp,
+  _stopSession,
+  activeSessions,
 };

tests/homekit-hangup-grace.test.cjs

@@ -187,3 +187,73 @@ test('shutdown drops a pending hangup', async () => {
   await sleep(GRACE_MS * 2);
   assert.deepEqual(hangUps, [], 'a hangup must not fire against a process that is going away');
 });
+
+// ---------------------------------------------------------------------------
+// Through _stopSession, the path the live bug was actually on.
+//
+// 2026-09-12: calls died three seconds into the stream. HomeKit runs up to
+// cameraStreamCount sessions at once and starts a second one when you move
+// between the room view's camera tile and the full camera view. The STOP for
+// that second session scheduled a hangup while the first was still streaming.
+// Driving scheduleHangUp directly, as the cases above do, cannot see this: the
+// fault was in whether to schedule at all, not in the timer.
+// ---------------------------------------------------------------------------
+
+/** A session bare enough for _stopSession: no ffmpeg, no SDP to clean up. */
+function fakeSession(id) {
+  homekit.activeSessions.set(id, {});
+  return id;
+}
+
+test('a stop with another session still streaming does not end the call', async () => {
+  reset('CA-two-sessions');
+  fakeSession('session-a');
+  fakeSession('session-b');
+
+  homekit._stopSession('session-b', /* hangUp= */ true);
+
+  await sleep(GRACE_MS * 2);
+  assert.deepEqual(hangUps, [], 'the surviving session is still streaming; the call must live');
+  assert.equal(homekit.activeSessions.size, 1, 'only the stopped session should be gone');
+
+  homekit.activeSessions.clear();
+});
+
+test('the last session stopping does end the call', async () => {
+  reset('CA-last-session');
+  fakeSession('session-only');
+
+  homekit._stopSession('session-only', /* hangUp= */ true);
+
+  assert.deepEqual(
+    await waitForHangUp(),
+    ['CA-last-session'],
+    'with no sessions left the user is finished and the call must end'
+  );
+});
+
+test('stopping every session in turn ends the call exactly once', async () => {
+  reset('CA-drain');
+  fakeSession('session-a');
+  fakeSession('session-b');
+
+  homekit._stopSession('session-a', /* hangUp= */ true);
+  homekit._stopSession('session-b', /* hangUp= */ true);
+
+  await waitForHangUp();
+  await sleep(GRACE_MS);
+  assert.deepEqual(hangUps, ['CA-drain'], 'draining the sessions must not hang up twice');
+});
+
+test('a caller-initiated teardown never hangs up, whatever is streaming', async () => {
+  // endHapSession runs on the Twilio stop: the call is already gone.
+  reset('CA-caller-left');
+  fakeSession('session-a');
+  fakeSession('session-b');
+
+  homekit.endHapSession();
+
+  await sleep(GRACE_MS * 2);
+  assert.deepEqual(hangUps, [], 'the caller hung up; there is nothing left to hang up');
+  assert.equal(homekit.activeSessions.size, 0, 'endHapSession must drain every session');
+});