Fix a TypeError when deleting the watched folder on Windows

src/watchdog/observers/winapi.py

@@ -295,7 +295,7 @@ def _is_observed_path_deleted(handle, path):
 def _generate_observed_path_deleted_event():
     # Create synthetic event for notify that observed directory is deleted
     path = ctypes.create_unicode_buffer('.')
-    event = FILE_NOTIFY_INFORMATION(0, FILE_ACTION_DELETED_SELF, len(path), path.value)
+    event = FILE_NOTIFY_INFORMATION(0, FILE_ACTION_DELETED_SELF, len(path), path.value.encode("utf-8"))
     event_size = ctypes.sizeof(event)
     buff = ctypes.create_string_buffer(BUFFER_SIZE)
     ctypes.memmove(buff, ctypes.addressof(event), event_size)

tests/test_observers_winapi.py

@@ -22,6 +22,7 @@
 if not platform.is_windows():  # noqa
     pytest.skip("Windows only.", allow_module_level=True)
 
+import os
 import os.path
 from time import sleep
 
@@ -36,11 +37,16 @@
 from .shell import (
     mkdir,
     mkdtemp,
-    mv
+    mv,
+    rm
 )
 
 
-temp_dir = mkdtemp()
+SLEEP_TIME = 2
+
+# Path with non-ASCII
+temp_dir = os.path.join(mkdtemp(), u"Strange \N{SNOWMAN}")
+os.makedirs(temp_dir)
 
 
 def p(*args):
@@ -65,8 +71,6 @@ def emitter(event_queue):
 
 
 def test___init__(event_queue, emitter):
-    SLEEP_TIME = 2
-
     emitter.start()
     sleep(SLEEP_TIME)
     mkdir(p('fromdir'))
@@ -98,3 +102,46 @@ def test___init__(event_queue, emitter):
             got.add(event)
 
     assert expected == got
+
+
+def test_root_deleted(event_queue, emitter):
+    r"""Test the event got when removing the watched folder.
+        The regression to prevent is:
+
+            Exception in thread Thread-1:
+            Traceback (most recent call last):
+            File "watchdog\observers\winapi.py", line 333, in read_directory_changes
+                ctypes.byref(nbytes), None, None)
+            File "watchdog\observers\winapi.py", line 105, in _errcheck_bool
+                raise ctypes.WinError()
+            PermissionError: [WinError 5] Access refused.
+
+            During handling of the above exception, another exception occurred:
+
+            Traceback (most recent call last):
+            File "C:\Python37-32\lib\threading.py", line 926, in _bootstrap_inner
+                self.run()
+            File "watchdog\observers\api.py", line 145, in run
+                self.queue_events(self.timeout)
+            File "watchdog\observers\read_directory_changes.py", line 76, in queue_events
+                winapi_events = self._read_events()
+            File "watchdog\observers\read_directory_changes.py", line 73, in _read_events
+                return read_events(self._handle, self.watch.path, self.watch.is_recursive)
+            File "watchdog\observers\winapi.py", line 387, in read_events
+                buf, nbytes = read_directory_changes(handle, path, recursive)
+            File "watchdog\observers\winapi.py", line 340, in read_directory_changes
+                return _generate_observed_path_deleted_event()
+            File "watchdog\observers\winapi.py", line 298, in _generate_observed_path_deleted_event
+                event = FILE_NOTIFY_INFORMATION(0, FILE_ACTION_DELETED_SELF, len(path), path.value)
+            TypeError: expected bytes, str found
+    """
+
+    emitter.start()
+    sleep(SLEEP_TIME)
+
+    # This should not fail
+    rm(p(), recursive=True)
+    sleep(SLEEP_TIME)
+
+    # The emitter is automatically stopped, with no error
+    assert not emitter.should_keep_running()