mypy check_untyped_defs

mypy.ini

@@ -8,10 +8,15 @@ disallow_subclassing_any = True
 ;disallow_untyped_calls = True
 ;disallow_untyped_defs = True
 disallow_incomplete_defs = True
-;check_untyped_defs = True
+check_untyped_defs = True
 disallow_untyped_decorators = True
 no_implicit_optional = True
 warn_return_any = True
 no_implicit_reexport = True
 strict_equality = True
 warn_redundant_casts = True
+
+[mypy-watchdog.watchmedo]
+# unable to handle platform detection overrides
+# https://github.com/python/mypy/issues/8823
+warn_unused_ignores = False

src/watchdog/events.py

@@ -562,17 +562,17 @@ def generate_sub_moved_events(src_dir_path, dest_dir_path):
             renamed_path = (
                 full_path.replace(dest_dir_path, src_dir_path) if src_dir_path else None
             )
-            event = DirMovedEvent(renamed_path, full_path)
-            event.is_synthetic = True
-            yield event
+            dir_moved_event = DirMovedEvent(renamed_path, full_path)
+            dir_moved_event.is_synthetic = True
+            yield dir_moved_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
             )
-            event = FileMovedEvent(renamed_path, full_path)
-            event.is_synthetic = True
-            yield event
+            file_moved_event = FileMovedEvent(renamed_path, full_path)
+            file_moved_event.is_synthetic = True
+            yield file_moved_event
 
 
 def generate_sub_created_events(src_dir_path):
@@ -588,10 +588,10 @@ def generate_sub_created_events(src_dir_path):
     """
     for root, directories, filenames in os.walk(src_dir_path):
         for directory in directories:
-            event = DirCreatedEvent(os.path.join(root, directory))
-            event.is_synthetic = True
-            yield event
+            dir_created_event = DirCreatedEvent(os.path.join(root, directory))
+            dir_created_event.is_synthetic = True
+            yield dir_created_event
         for filename in filenames:
-            event = FileCreatedEvent(os.path.join(root, filename))
-            event.is_synthetic = True
-            yield event
+            file_created_event = FileCreatedEvent(os.path.join(root, filename))
+            file_created_event.is_synthetic = True
+            yield file_created_event

src/watchdog/observers/__init__.py

@@ -55,9 +55,9 @@
 from typing import Type
 
 from watchdog.utils import UnsupportedLibc
-from .api import BaseObserver
+from .api import BaseObserverSubclassCallable
 
-Observer: Type[BaseObserver]
+Observer: BaseObserverSubclassCallable
 
 
 if sys.platform.startswith("linux"):

src/watchdog/observers/api.py

@@ -16,6 +16,7 @@
 import queue
 import threading
 from pathlib import Path
+from typing import Protocol
 
 from watchdog.utils import BaseThread
 from watchdog.utils.bricks import SkipRepeatsQueue
@@ -377,3 +378,8 @@ def dispatch_events(self, event_queue):
                 if handler in self._handlers.get(watch, []):
                     handler.dispatch(event)
         event_queue.task_done()
+
+
+class BaseObserverSubclassCallable(Protocol):
+    def __call__(self, timeout: float = ...) -> BaseObserver:
+        ...

src/watchdog/observers/fsevents2.py

@@ -24,12 +24,14 @@
 import unicodedata
 import warnings
 from threading import Thread
+from typing import List, Optional, Type
 
 from watchdog.events import (
     FileDeletedEvent,
     FileModifiedEvent,
     FileCreatedEvent,
     FileMovedEvent,
+    FileSystemEvent,
     DirDeletedEvent,
     DirModifiedEvent,
     DirCreatedEvent,
@@ -86,7 +88,7 @@ class FSEventsQueue(Thread):
 
     def __init__(self, path):
         Thread.__init__(self)
-        self._queue = queue.Queue()
+        self._queue: queue.Queue[Optional[List[NativeEvent]]] = queue.Queue()
         self._run_loop = None
 
         if isinstance(path, bytes):
@@ -212,6 +214,7 @@ def queue_events(self, timeout):
         while i < len(events):
             event = events[i]
 
+            cls: Type[FileSystemEvent]
             # For some reason the create and remove flags are sometimes also
             # set for rename and modify type events, so let those take
             # precedence.

src/watchdog/observers/inotify.py

@@ -64,8 +64,10 @@
 
 """
 
+import logging
 import os
 import threading
+from typing import Type
 from .inotify_buffer import InotifyBuffer
 
 from watchdog.observers.api import (
@@ -86,11 +88,15 @@
     FileCreatedEvent,
     FileClosedEvent,
     FileOpenedEvent,
+    FileSystemEvent,
     generate_sub_moved_events,
     generate_sub_created_events,
 )
 
 
+logger = logging.getLogger(__name__)
+
+
 class InotifyEmitter(EventEmitter):
     """
     inotify(7)-based event emitter.
@@ -125,9 +131,14 @@ def queue_events(self, timeout, full_events=False):
         # If "full_events" is true, then the method will report unmatched move events as separate events
         # This behavior is by default only called by a InotifyFullEmitter
         with self._lock:
+            if self._inotify is None:
+                logger.error("InotifyEmitter.queue_events() called when the thread is inactive")
+                return
             event = self._inotify.read_event()
             if event is None:
                 return
+
+            cls: Type[FileSystemEvent]
             if isinstance(event, tuple):
                 move_from, move_to = event
                 src_path = self._decode_path(move_from.src_path)

src/watchdog/observers/inotify_buffer.py

@@ -13,9 +13,11 @@
 # limitations under the License.
 
 import logging
+from typing import List, TYPE_CHECKING, Tuple, Union
+
 from watchdog.utils import BaseThread
 from watchdog.utils.delayed_queue import DelayedQueue
-from watchdog.observers.inotify_c import Inotify
+from watchdog.observers.inotify_c import Inotify, InotifyEvent
 
 logger = logging.getLogger(__name__)
 
@@ -29,7 +31,7 @@ class InotifyBuffer(BaseThread):
 
     def __init__(self, path, recursive=False):
         super().__init__()
-        self._queue = DelayedQueue(self.delay)
+        self._queue = DelayedQueue[InotifyEvent](self.delay)
         self._inotify = Inotify(path, recursive)
         self.start()
 
@@ -50,7 +52,7 @@ def close(self):
 
     def _group_events(self, event_list):
         """Group any matching move events"""
-        grouped = []
+        grouped: List[Union[InotifyEvent, Tuple[InotifyEvent, InotifyEvent]]] = []
         for inotify_event in event_list:
             logger.debug("in-event %s", inotify_event)
 
@@ -65,6 +67,9 @@ def matching_from_event(event):
                 # Check if move_from is already in the buffer
                 for index, event in enumerate(grouped):
                     if matching_from_event(event):
+                        if TYPE_CHECKING:
+                            # this check is hidden from mypy inside matching_from_event()
+                            assert not isinstance(event, tuple)
                         grouped[index] = (event, inotify_event)
                         break
                 else:

src/watchdog/tricks/__init__.py

@@ -44,6 +44,7 @@
 import os
 import signal
 import subprocess
+import sys
 import threading
 import time
 
@@ -320,7 +321,7 @@ def _restart_process(self):
         self.restart_count += 1
 
 
-if hasattr(os, "getpgid") and hasattr(os, "killpg"):
+if not sys.platform.startswith("win"):
 
     def kill_process(pid, stop_signal):
         os.killpg(os.getpgid(pid), stop_signal)

src/watchdog/utils/delayed_queue.py

@@ -15,17 +15,21 @@
 import time
 import threading
 from collections import deque
+from typing import Callable, Deque, Generic, Optional, Tuple, TypeVar
 
 
-class DelayedQueue:
+T = TypeVar("T")
+
+
+class DelayedQueue(Generic[T]):
     def __init__(self, delay):
         self.delay_sec = delay
         self._lock = threading.Lock()
         self._not_empty = threading.Condition(self._lock)
-        self._queue = deque()
+        self._queue: Deque[Tuple[T, float, bool]] = deque()
         self._closed = False
 
-    def put(self, element, delay=False):
+    def put(self, element: T, delay: bool = False) -> None:
         """Add element to queue."""
         self._lock.acquire()
         self._queue.append((element, time.time(), delay))
@@ -40,7 +44,7 @@ def close(self):
         self._not_empty.notify()
         self._not_empty.release()
 
-    def get(self):
+    def get(self) -> Optional[T]:
         """Remove and return an element from the queue, or this queue has been
         closed raise the Closed exception.
         """
@@ -69,7 +73,7 @@ def get(self):
                     self._queue.popleft()
                     return head
 
-    def remove(self, predicate):
+    def remove(self, predicate: Callable[[T], bool]) -> Optional[T]:
         """Remove and return the first items for which predicate is True,
         ignoring delay."""
         with self._lock:

src/watchdog/watchmedo.py

@@ -30,7 +30,9 @@
 from argparse import ArgumentParser, RawDescriptionHelpFormatter
 from io import StringIO
 from textwrap import dedent
+from typing import TYPE_CHECKING, Type
 
+from watchdog.observers.api import BaseObserverSubclassCallable
 from watchdog.utils import WatchdogShutdown, load_class
 from watchdog.version import VERSION_STRING
 
@@ -263,12 +265,13 @@ def tricks_from(args):
     """
     Command to execute tricks from a tricks configuration file.
     """
+    Observer: BaseObserverSubclassCallable
     if args.debug_force_polling:
         from watchdog.observers.polling import PollingObserver as Observer
     elif args.debug_force_kqueue:
         from watchdog.observers.kqueue import KqueueObserver as Observer
     elif args.debug_force_winapi:
-        from watchdog.observers.read_directory_changes import (
+        from watchdog.observers.read_directory_changes import (  # type:ignore[attr-defined,no-redef]
             WindowsApiObserver as Observer,
         )
     elif args.debug_force_inotify:
@@ -376,8 +379,8 @@ def tricks_generate_yaml(args):
     else:
         if not os.path.exists(args.append_to_file):
             content = header + content
-        with open(args.append_to_file, "ab") as output:
-            output.write(content)
+        with open(args.append_to_file, "a", encoding="utf-8") as file:
+            file.write(content)
 
 
 @command(
@@ -471,12 +474,14 @@ def log(args):
         ignore_patterns=ignore_patterns,
         ignore_directories=args.ignore_directories,
     )
+
+    Observer: BaseObserverSubclassCallable
     if args.debug_force_polling:
         from watchdog.observers.polling import PollingObserver as Observer
     elif args.debug_force_kqueue:
         from watchdog.observers.kqueue import KqueueObserver as Observer
     elif args.debug_force_winapi:
-        from watchdog.observers.read_directory_changes import (
+        from watchdog.observers.read_directory_changes import (  # type:ignore[attr-defined,no-redef]
             WindowsApiObserver as Observer,
         )
     elif args.debug_force_inotify:
@@ -587,6 +592,7 @@ def shell_command(args):
     if not args.command:
         args.command = None
 
+    Observer: BaseObserverSubclassCallable
     if args.debug_force_polling:
         from watchdog.observers.polling import PollingObserver as Observer
     else:
@@ -706,6 +712,7 @@ def auto_restart(args):
     Command to start a long-running subprocess and restart it on matched events.
     """
 
+    Observer: BaseObserverSubclassCallable
     if args.debug_force_polling:
         from watchdog.observers.polling import PollingObserver as Observer
     else:

tests/test_delayed_queue.py

@@ -20,7 +20,7 @@
 
 @pytest.mark.flaky(max_runs=5, min_passes=1)
 def test_delayed_get():
-    q = DelayedQueue(2)
+    q = DelayedQueue[str](2)
     q.put("", True)
     inserted = time()
     q.get()
@@ -31,7 +31,7 @@ def test_delayed_get():
 
 @pytest.mark.flaky(max_runs=5, min_passes=1)
 def test_nondelayed_get():
-    q = DelayedQueue(2)
+    q = DelayedQueue[str](2)
     q.put("", False)
     inserted = time()
     q.get()