[windows] Remove the WATCHDOG_TRAVERSE_MOVED_DIR_DELAY hack (#986)

The `observers.read_directory_changes.WATCHDOG_TRAVERSE_MOVED_DIR_DELAY` hack was removed.
The constant will be kept to prevent breaking other softwares.

changelog.rst

@@ -13,6 +13,7 @@ Changelog
 - [events] Log ``FileOpenedEvent``, and ``FileClosedEvent``, events in ``LoggingEventHandler``
 - [tests] Improve ``FileSystemEvent`` coverage
 - [watchmedo] Log all events in ``LoggerTrick``
+- [windows] The ``observers.read_directory_changes.WATCHDOG_TRAVERSE_MOVED_DIR_DELAY`` hack was removed. The constant will be kept to prevent breaking other softwares.
 - Thanks to our beloved contributors: @BoboTiG
 
 3.0.0

src/watchdog/observers/read_directory_changes.py

@@ -20,7 +20,6 @@
 import platform
 import sys
 import threading
-import time
 
 from watchdog.events import (
     DirCreatedEvent,
@@ -40,7 +39,7 @@
 
 from watchdog.observers.winapi import close_directory_handle, get_directory_handle, read_events  # noqa: E402
 
-# HACK:
+# Obsolete constant, it's no more used since v4.0.0.
 WATCHDOG_TRAVERSE_MOVED_DIR_DELAY = 1  # seconds
 
 
@@ -62,8 +61,10 @@ def on_thread_start(self):
 
         def start(self):
             """PyPy needs some time before receiving events, see #792."""
+            from time import sleep
+
             super().start()
-            time.sleep(0.01)
+            sleep(0.01)
 
     def on_thread_stop(self):
         if self._handle:
@@ -85,23 +86,10 @@ def queue_events(self, timeout):
                     dest_path = src_path
                     src_path = last_renamed_src_path
                     if os.path.isdir(dest_path):
-                        event = DirMovedEvent(src_path, dest_path)
+                        self.queue_event(DirMovedEvent(src_path, dest_path))
                         if self.watch.is_recursive:
-                            # HACK: We introduce a forced delay before
-                            # traversing the moved directory. This will read
-                            # only file movement that finishes within this
-                            # delay time.
-                            time.sleep(WATCHDOG_TRAVERSE_MOVED_DIR_DELAY)
-                            # The following block of code may not
-                            # obtain moved events for the entire tree if
-                            # the I/O is not completed within the above
-                            # delay time. So, it's not guaranteed to work.
-                            # TODO: Come up with a better solution, possibly
-                            # a way to wait for I/O to complete before
-                            # queuing events.
                             for sub_moved_event in generate_sub_moved_events(src_path, dest_path):
                                 self.queue_event(sub_moved_event)
-                        self.queue_event(event)
                     else:
                         self.queue_event(FileMovedEvent(src_path, dest_path))
                 elif winapi_event.is_modified:
@@ -112,12 +100,7 @@ def queue_events(self, timeout):
                     cls = DirCreatedEvent if isdir else FileCreatedEvent
                     self.queue_event(cls(src_path))
                     if isdir and self.watch.is_recursive:
-                        # If a directory is moved from outside the watched folder to inside it
-                        # we only get a created directory event out of it, not any events for its children
-                        # so use the same hack as for file moves to get the child events
-                        time.sleep(WATCHDOG_TRAVERSE_MOVED_DIR_DELAY)
-                        sub_events = generate_sub_created_events(src_path)
-                        for sub_created_event in sub_events:
+                        for sub_created_event in generate_sub_created_events(src_path):
                             self.queue_event(sub_created_event)
                 elif winapi_event.is_removed:
                     self.queue_event(FileDeletedEvent(src_path))

tests/test_emitter.py

@@ -51,10 +51,7 @@
 
 def rerun_filter(exc, *args):
     time.sleep(5)
-    if issubclass(exc[0], Empty) and platform.is_windows():
-        return True
-
-    return False
+    return bool(issubclass(exc[0], Empty) and platform.is_windows())
 
 
 @pytest.mark.flaky(max_runs=5, min_passes=1, rerun_filter=rerun_filter)
@@ -449,7 +446,7 @@ def test_recursive_off(
         expect_event(DirModifiedEvent(p()))
 
 
-@pytest.mark.skipif(platform.is_windows(), reason="Windows create another set of events for this test")
+@pytest.mark.flaky(max_runs=5, min_passes=1, rerun_filter=rerun_filter)
 def test_renaming_top_level_directory(
     p: P,
     event_queue: TestEventQueue,
@@ -460,17 +457,18 @@ def test_renaming_top_level_directory(
 
     mkdir(p("a"))
     expect_event(DirCreatedEvent(p("a")))
-    expect_event(DirModifiedEvent(p()))
+    if not platform.is_windows():
+        expect_event(DirModifiedEvent(p()))
 
     mkdir(p("a", "b"))
     expect_event(DirCreatedEvent(p("a", "b")))
     expect_event(DirModifiedEvent(p("a")))
 
     mv(p("a"), p("a2"))
     expect_event(DirMovedEvent(p("a"), p("a2")))
-    expect_event(DirModifiedEvent(p()))
-    expect_event(DirModifiedEvent(p()))
-
+    if not platform.is_windows():
+        expect_event(DirModifiedEvent(p()))
+        expect_event(DirModifiedEvent(p()))
     expect_event(DirMovedEvent(p("a", "b"), p("a2", "b"), is_synthetic=True))
 
     if platform.is_bsd():
@@ -486,19 +484,8 @@ def test_renaming_top_level_directory(
             break
 
     assert all(
-        [
-            isinstance(
-                e,
-                (
-                    FileCreatedEvent,
-                    FileMovedEvent,
-                    FileOpenedEvent,
-                    DirModifiedEvent,
-                    FileClosedEvent,
-                ),
-            )
-            for e in events
-        ]
+        isinstance(e, (FileCreatedEvent, FileMovedEvent, FileOpenedEvent, DirModifiedEvent, FileClosedEvent))
+        for e in events
     )
 
     for event in events:
@@ -511,64 +498,6 @@ def test_renaming_top_level_directory(
             assert event.src_path == p("a2", "b")
 
 
-@pytest.mark.flaky(max_runs=5, min_passes=1, rerun_filter=rerun_filter)
-@pytest.mark.skipif(
-    not platform.is_windows(),
-    reason="Non-Windows create another set of events for this test",
-)
-def test_renaming_top_level_directory_on_windows(
-    p: P,
-    event_queue: TestEventQueue,
-    start_watching: StartWatching,
-) -> None:
-    start_watching()
-
-    mkdir(p("a"))
-    event = event_queue.get(timeout=5)[0]
-    assert isinstance(event, DirCreatedEvent)
-    assert event.src_path == p("a")
-
-    mkdir(p("a", "b"))
-    event = event_queue.get(timeout=5)[0]
-    assert isinstance(event, DirCreatedEvent)
-    assert event.src_path == p("a", "b")
-
-    event = event_queue.get(timeout=5)[0]
-    assert isinstance(event, DirCreatedEvent)
-    assert event.src_path == p("a", "b")
-
-    event = event_queue.get(timeout=5)[0]
-    assert isinstance(event, DirModifiedEvent)
-    assert event.src_path == p("a")
-
-    mv(p("a"), p("a2"))
-    event = event_queue.get(timeout=5)[0]
-    assert isinstance(event, DirMovedEvent)
-    assert event.src_path == p("a", "b")
-
-    open(p("a2", "b", "c"), "a").close()
-
-    events = []
-    while True:
-        events.append(event_queue.get(timeout=5)[0])
-        if event_queue.empty():
-            break
-
-    assert all(isinstance(e, (FileCreatedEvent, FileMovedEvent, DirMovedEvent, DirModifiedEvent)) for e in events)
-
-    for event in events:
-        if isinstance(event, FileCreatedEvent):
-            assert event.src_path == p("a2", "b", "c")
-        elif isinstance(event, FileMovedEvent):
-            assert event.dest_path == p("a2", "b", "c")
-            assert event.src_path == p("a", "b", "c")
-        elif isinstance(event, DirMovedEvent):
-            assert event.dest_path == p("a2")
-            assert event.src_path == p("a")
-        elif isinstance(event, DirModifiedEvent):
-            assert event.src_path == p("a2", "b")
-
-
 @pytest.mark.skipif(platform.is_windows(), reason="Windows create another set of events for this test")
 def test_move_nested_subdirectories(
     p: P,