Identify synthesized events

Original patch by @skurfer in gorakhargosh#369.

changelog.rst

@@ -24,6 +24,7 @@ API changes
 - ``WindowsApiEmitter`` made easier to subclass.
 - Use separate ctypes DLL instances on Windows.
 - Added ``--debug-force-polling`` arguments to watchmedo.
+- Identify synthesized events with ``is_synthetic`` attribute.
 - Refactored tests to use pytest.
 - General code clean-up.
 

src/watchdog/events.py

@@ -114,6 +114,14 @@ class FileSystemEvent(object):
     is_directory = False
     """True if event was emitted for a directory; False otherwise."""
 
+    is_synthetic = False
+    """
+    True if event was synthesized; False otherwise.
+
+    These are events that weren't actually broadcast by the OS, but
+    are presumed to have happened based on other, actual events.
+    """
+
     def __init__(self, src_path):
         self._src_path = src_path
 
@@ -590,11 +598,15 @@ def generate_sub_moved_events(src_dir_path, dest_dir_path):
         for directory in directories:
             full_path = os.path.join(root, directory)
             renamed_path = full_path.replace(dest_dir_path, src_dir_path) if src_dir_path else None
-            yield DirMovedEvent(renamed_path, full_path)
+            event = DirMovedEvent(renamed_path, full_path)
+            event.is_synthetic = True
+            yield event
         for filename in filenames:
             full_path = os.path.join(root, filename)
             renamed_path = full_path.replace(dest_dir_path, src_dir_path) if src_dir_path else None
-            yield FileMovedEvent(renamed_path, full_path)
+            event = FileMovedEvent(renamed_path, full_path)
+            event.is_synthetic = True
+            yield event
 
 
 def generate_sub_created_events(src_dir_path):
@@ -610,6 +622,10 @@ def generate_sub_created_events(src_dir_path):
     """
     for root, directories, filenames in os.walk(src_dir_path):
         for directory in directories:
-            yield DirCreatedEvent(os.path.join(root, directory))
+            event = DirCreatedEvent(os.path.join(root, directory))
+            event.is_synthetic = True
+            yield event
         for filename in filenames:
-            yield FileCreatedEvent(os.path.join(root, filename))
+            event = FileCreatedEvent(os.path.join(root, filename))
+            event.is_synthetic = True
+            yield event

src/watchdog/observers/inotify.py

@@ -125,8 +125,8 @@ def on_thread_stop(self):
             self._inotify.close()
 
     def queue_events(self, timeout, full_events=False):
-        #If "full_events" is true, then the method will report unmatched move events as seperate events
-        #This behavior is by default only called by a InotifyFullEmitter
+        # If "full_events" is true, then the method will report unmatched move events as seperate events
+        # This behavior is by default only called by a InotifyFullEmitter
         with self._lock:
             event = self._inotify.read_event()
             if event is None:
@@ -146,7 +146,7 @@ def queue_events(self, timeout, full_events=False):
 
             src_path = self._decode_path(event.src_path)
             if event.is_moved_to:
-                if (full_events):
+                if full_events:
                     cls = DirMovedEvent if event.is_directory else FileMovedEvent
                     self.queue_event(cls(None, src_path))
                 else:

tests/test_events.py

@@ -41,32 +41,37 @@ def test_file_deleted_event():
     assert path_1 == event.src_path
     assert EVENT_TYPE_DELETED == event.event_type
     assert not event.is_directory
+    assert not event.is_synthetic
 
 
 def test_file_delete_event_is_directory():
     # Inherited properties.
-    event1 = FileDeletedEvent(path_1)
-    assert not event1.is_directory
+    event = FileDeletedEvent(path_1)
+    assert not event.is_directory
+    assert not event.is_synthetic
 
 
 def test_file_modified_event():
     event = FileModifiedEvent(path_1)
     assert path_1 == event.src_path
     assert EVENT_TYPE_MODIFIED == event.event_type
     assert not event.is_directory
+    assert not event.is_synthetic
 
 
 def test_file_modified_event_is_directory():
     # Inherited Properties
-    event1 = FileModifiedEvent(path_1)
-    assert not event1.is_directory
+    event = FileModifiedEvent(path_1)
+    assert not event.is_directory
+    assert not event.is_synthetic
 
 
 def test_file_created_event():
     event = FileCreatedEvent(path_1)
     assert path_1 == event.src_path
     assert EVENT_TYPE_CREATED == event.event_type
     assert not event.is_directory
+    assert not event.is_synthetic
 
 
 def test_file_moved_event():
@@ -75,27 +80,31 @@ def test_file_moved_event():
     assert path_2 == event.dest_path
     assert EVENT_TYPE_MOVED == event.event_type
     assert not event.is_directory
+    assert not event.is_synthetic
 
 
 def test_dir_deleted_event():
     event = DirDeletedEvent(path_1)
     assert path_1 == event.src_path
     assert EVENT_TYPE_DELETED == event.event_type
     assert event.is_directory
+    assert not event.is_synthetic
 
 
 def test_dir_modified_event():
     event = DirModifiedEvent(path_1)
     assert path_1 == event.src_path
     assert EVENT_TYPE_MODIFIED == event.event_type
     assert event.is_directory
+    assert not event.is_synthetic
 
 
 def test_dir_created_event():
     event = DirCreatedEvent(path_1)
     assert path_1 == event.src_path
     assert EVENT_TYPE_CREATED == event.event_type
     assert event.is_directory
+    assert not event.is_synthetic
 
 
 def test_file_system_event_handler_dispatch():
@@ -139,4 +148,5 @@ def on_created(self, event):
     handler = TestableEventHandler()
 
     for event in all_events:
+        assert not event.is_synthetic
         handler.dispatch(event)