Patch from #788

src/watchdog/observers/fsevents.py

@@ -86,11 +86,8 @@ def __init__(self, event_queue, watch, timeout=DEFAULT_EMITTER_TIMEOUT, suppress
         self._lock = threading.RLock()
 
     def on_thread_stop(self):
-        if self.watch:
-            _fsevents.remove_watch(self.watch)
-            _fsevents.stop(self)
-            with self._lock:
-                self._watch = None
+        _fsevents.remove_watch(self.watch)
+        _fsevents.stop(self)
 
     def queue_event(self, event):
         # fsevents defaults to be recursive, so if the watch was meant to be non-recursive then we need to drop

src/watchdog_fsevents.c

@@ -784,17 +784,20 @@ static PyObject *
 watchdog_remove_watch(PyObject *self, PyObject *watch)
 {
     UNUSED(self);
-    PyObject *value = PyDict_GetItem(watch_to_stream, watch);
+    PyObject *streamref_capsule = PyDict_GetItem(watch_to_stream, watch);
+    if (!streamref_capsule) {
+        // A watch might have been removed explicitly before, in which case we can simply early out.
+        Py_RETURN_NONE;
+    }
     PyDict_DelItem(watch_to_stream, watch);
 
-    FSEventStreamRef stream_ref = PyCapsule_GetPointer(value, NULL);
+    FSEventStreamRef stream_ref = PyCapsule_GetPointer(streamref_capsule, NULL);
 
     FSEventStreamStop(stream_ref);
     FSEventStreamInvalidate(stream_ref);
     FSEventStreamRelease(stream_ref);
 
-    Py_INCREF(Py_None);
-    return Py_None;
+    Py_RETURN_NONE;
 }
 
 PyDoc_STRVAR(watchdog_stop__doc__,

tests/test_fsevents.py

@@ -227,9 +227,7 @@ def on_thread_stop(self):
     w = observer.schedule(FileSystemEventHandler(), a, recursive=False)
     rmdir(a)
     time.sleep(0.1)
-    with pytest.raises(KeyError):
-        # watch no longer exists!
-        observer.unschedule(w)
+    observer.unschedule(w)
 
 
 def test_converting_cfstring_to_pyunicode():