Robustify pyside

src/qasync/__init__.py

@@ -354,7 +354,9 @@
     The set_running_loop parameter is there for backwards compatibility and does nothing.
     """
 
-    def __init__(self, app=None, set_running_loop=False, already_running=False):
+    def __init__(
+        self, app=None, set_running_loop=False, already_running=False, qtparent=None
+    ):
         self.__app = app or QApplication.instance()
         assert self.__app is not None, "No QApplication has been instantiated"
         self.__is_running = False
@@ -364,8 +366,10 @@
         self._read_notifiers = {}
         self._write_notifiers = {}
         self._timer = _SimpleTimer()
+        self.qtparent = qtparent or self.__app
 
         self.__call_soon_signaller = signaller = _make_signaller(QtCore, object, tuple)
+
         self.__call_soon_signal = signaller.signal
         self.__call_soon_signal.connect(
             lambda callback, args: self.call_soon(callback, *args)
@@ -374,6 +378,18 @@
         assert self.__app is not None
         super().__init__()
 
+        # Parent helper objects, such as timers, to this Qt parent for safe
+        # lifetime management.
+        if (
+            self.qtparent is not None
+            and self.qtparent.thread() is not QtCore.QThread.currentThread()
+        ):
+            raise RuntimeError(
+                "qt_parent must belong to the same QThread as the event loop"
+            )
+        self._timer.setParent(self.qtparent)
+        signaller.setParent(self.qtparent)
+
         # We have to set __is_running to True after calling
         # super().__init__() because of a bug in BaseEventLoop.
         if already_running:
@@ -385,8 +401,11 @@
             self.__app.aboutToQuit.connect(self._after_run_forever)
 
             # for asyncio to recognize the already running loop
             asyncio.events._set_running_loop(self)
 
+    def get_qtparent(self):
+        return self.qtparent
+
     def run_forever(self):
         """Run eventloop forever."""
 
@@ -463,26 +482,53 @@
         if self.is_closed():
             return
 
+        # the following code places try/catch around possibly failing
+        # operations for safety and to guard against implementation
+        # difference in the QT bindings.
+
         self.__log_debug("Closing event loop...")
+        # Catch exceptions for safety between bindings.
+        try:
+            poller = self.get_proactor_event_poller()
+        except AttributeError:
+            pass
+        else:
+            poller.stop()
+
         if self.__default_executor is not None:
             self.__default_executor.shutdown()
 
-        if self.__call_soon_signal:
+        # Disconnect thread-safe signaller and schedule deletion of helper QObjects
+        try:
             self.__call_soon_signal.disconnect()
+        except Exception:  # pragma: no cover
+            pass
+        try:
+            # may raise if already deleted
+            self.__call_soon_signaller.deleteLater()
+        except Exception:  # pragma: no cover
+            pass
 
-        super().close()
-
+        # Stop timers first to avoid late invocations during teardown
         self._timer.stop()
-        self.__app = None
+        try:
+            self._timer.deleteLater()
+        except Exception:  # pragma: no cover
+            pass
 
+        # Disable and disconnect any remaining notifiers before closing
         for notifier in itertools.chain(
             self._read_notifiers.values(), self._write_notifiers.values()
         ):
-            notifier.setEnabled(False)
-            notifier.activated["int"].disconnect()
+            self._delete_notifier(notifier)
 
-        self._read_notifiers = None
-        self._write_notifiers = None
+        self._read_notifiers.clear()
+        self._write_notifiers.clear()
+
+        super().close()
+
+        # Finally, clear app reference
+        self.__app = None
 
     def call_later(self, delay, callback, *args, context=None):
         """Register callback to be invoked after a certain delay."""
@@ -531,15 +577,16 @@
             pass
         else:
             # this is necessary to avoid race condition-like issues
-            existing.setEnabled(False)
-            existing.activated["int"].disconnect()
+            self._delete_notifier(existing)
             # will get overwritten by the assignment below anyways
 
-        notifier = QtCore.QSocketNotifier(_fileno(fd), QtCore.QSocketNotifier.Type.Read)
+        notifier = QtCore.QSocketNotifier(
+            _fileno(fd), QtCore.QSocketNotifier.Type.Read, self.__app
+        )
         notifier.setEnabled(True)
         self.__log_debug("Adding reader callback for file descriptor %s", fd)
         notifier.activated["int"].connect(
-            lambda: self.__on_notifier_ready(
+            lambda *_: self.__on_notifier_ready(
                 self._read_notifiers, notifier, fd, callback, args
             )  # noqa: C812
         )
@@ -556,8 +603,7 @@
         except KeyError:
             return False
         else:
-            notifier.setEnabled(False)
-            notifier.activated["int"].disconnect()
+            self._delete_notifier(notifier)
             return True
 
     def _add_writer(self, fd, callback, *args):
@@ -569,18 +615,18 @@
             pass
         else:
             # this is necessary to avoid race condition-like issues
-            existing.setEnabled(False)
-            existing.activated["int"].disconnect()
+            self._delete_notifier(existing)
             # will get overwritten by the assignment below anyways
 
         notifier = QtCore.QSocketNotifier(
             _fileno(fd),
             QtCore.QSocketNotifier.Type.Write,
+            self.__app,
         )
         notifier.setEnabled(True)
         self.__log_debug("Adding writer callback for file descriptor %s", fd)
         notifier.activated["int"].connect(
-            lambda: self.__on_notifier_ready(
+            lambda *_: self.__on_notifier_ready(
                 self._write_notifiers, notifier, fd, callback, args
             )  # noqa: C812
         )
@@ -597,8 +643,7 @@
         except KeyError:
             return False
         else:
-            notifier.setEnabled(False)
-            notifier.activated["int"].disconnect()
+            self._delete_notifier(notifier)
             return True
 
     def __notifier_cb_wrapper(self, notifiers, notifier, fd, callback, args):
@@ -616,15 +661,14 @@
                 notifier.setEnabled(True)
 
     def __on_notifier_ready(self, notifiers, notifier, fd, callback, args):
-        if fd not in notifiers:
+        if fd not in notifiers:  # pragma: no cover
             self._logger.warning(
                 "Socket notifier for fd %s is ready, even though it should "
                 "be disabled, not calling %s and disabling",
                 fd,
                 callback,
             )
-            notifier.setEnabled(False)
-            notifier.activated["int"].disconnect()
+            self._delete_notifier(notifier)
             return
 
         # It can be necessary to disable QSocketNotifier when e.g. checking
@@ -636,6 +680,18 @@
             self.__notifier_cb_wrapper, notifiers, notifier, fd, callback, args
         )
 
+    @staticmethod
+    def _delete_notifier(notifier):
+        notifier.setEnabled(False)
+        try:
+            notifier.activated["int"].disconnect()
+        except Exception:  # pragma: no cover
+            pass
+        try:
+            notifier.deleteLater()
+        except Exception:  # pragma: no cover
+            pass
+
     # Methods for interacting with threads.
 
     def call_soon_threadsafe(self, callback, *args, context=None):

src/qasync/_unix.py

@@ -10,13 +10,17 @@
 
 import asyncio
 import collections
+import itertools
 import selectors
 
 from . import QtCore, _fileno, with_logger
 
 EVENT_READ = 1 << 0
 EVENT_WRITE = 1 << 1
 
+# Qt5/Qt6 compatibility
+NotifierEnum = getattr(QtCore.QSocketNotifier, "Type", QtCore.QSocketNotifier)
+
 
 class _SelectorMapping(collections.abc.Mapping):
     """Mapping of file objects to selector keys."""
@@ -40,14 +44,15 @@
 
 @with_logger
 class _Selector(selectors.BaseSelector):
-    def __init__(self, parent):
+    def __init__(self, parent, qtparent=None):
         # this maps file descriptors to keys
         self._fd_to_key = {}
         # read-only mapping returned by get_map()
         self.__map = _SelectorMapping(self)
         self.__read_notifiers = {}
         self.__write_notifiers = {}
         self.__parent = parent
+        self.__qtparent = qtparent
 
     def select(self, *args, **kwargs):
         """Implement abstract method even though we don't need it."""
@@ -83,16 +88,22 @@
         if key.fd in self._fd_to_key:
             raise KeyError("{!r} (FD {}) is already registered".format(fileobj, key.fd))
 
         self._fd_to_key[key.fd] = key
 
         if events & EVENT_READ:
-            notifier = QtCore.QSocketNotifier(key.fd, QtCore.QSocketNotifier.Read)
+            notifier = QtCore.QSocketNotifier(
+                key.fd, NotifierEnum.Read, self.__qtparent
+            )
+            notifier.setEnabled(True)
             notifier.activated["int"].connect(self.__on_read_activated)
             self.__read_notifiers[key.fd] = notifier
         if events & EVENT_WRITE:
-            notifier = QtCore.QSocketNotifier(key.fd, QtCore.QSocketNotifier.Write)
+            notifier = QtCore.QSocketNotifier(
+                key.fd, NotifierEnum.Write, self.__qtparent
+            )
+            notifier.setEnabled(True)
             notifier.activated["int"].connect(self.__on_write_activated)
             self.__write_notifiers[key.fd] = notifier
 
         return key
 
@@ -109,16 +120,16 @@
             self.__parent._process_event(key, EVENT_WRITE & key.events)
 
     def unregister(self, fileobj):
         def drop_notifier(notifiers):
             try:
                 notifier = notifiers.pop(key.fd)
-            except KeyError:
+            except KeyError:  # pragma: no cover
                 pass
             else:
-                notifier.activated["int"].disconnect()
+                self._delete_notifier(notifier)
 
         try:
             key = self._fd_to_key.pop(self._fileobj_lookup(fileobj))
         except KeyError:
             raise KeyError("{!r} is not registered".format(fileobj)) from None
 
@@ -144,6 +155,10 @@
     def close(self):
         self._logger.debug("Closing")
         self._fd_to_key.clear()
+        for notifier in itertools.chain(
+            self.__read_notifiers.values(), self.__write_notifiers.values()
+        ):
+            self._delete_notifier(notifier)
         self.__read_notifiers.clear()
         self.__write_notifiers.clear()
 
@@ -163,16 +178,36 @@
         """
         try:
             return self._fd_to_key[fd]
         except KeyError:
             return None
 
+    @staticmethod
+    def _delete_notifier(notifier):
+        notifier.setEnabled(False)
+        try:
+            notifier.activated["int"].disconnect()
+        except Exception:  # pragma: no cover
+            pass
+        try:
+            notifier.deleteLater()
+        except Exception:  # pragma: no cover
+            pass
+
 
 class _SelectorEventLoop(asyncio.SelectorEventLoop):
     def __init__(self):
         self._signal_safe_callbacks = []
 
-        selector = _Selector(self)
-        asyncio.SelectorEventLoop.__init__(self, selector)
+        try:
+            qtparent = self.get_qtparent()
+        except AttributeError:  # pragma: no cover
+            qtparent = None
+        self._qtselector = _Selector(self, qtparent=qtparent)
+        asyncio.SelectorEventLoop.__init__(self, self._qtselector)
+
+    def close(self):
+        self._qtselector.close()
+        super().close()
 
     def _before_run_forever(self):
         pass

src/qasync/_windows.py

@@ -38,6 +38,9 @@ def __init__(self):
         self.__event_signal.connect(self._process_events)
         self.__event_poller = _EventPoller(self.__event_signal)
 
+    def get_proactor_event_poller(self):
+        return self.__event_poller
+
     def _process_events(self, events):
         """Process events from proactor."""
         for f, callback, transferred, key, ov in events:
@@ -210,6 +213,7 @@ class _EventPoller:
 
     def __init__(self, sig_events):
         self.sig_events = sig_events
+        self.__worker = None
 
     def start(self, proactor):
         self._logger.debug("Starting (proactor: %s)...", proactor)
@@ -218,4 +222,6 @@ def start(self, proactor):
 
     def stop(self):
         self._logger.debug("Stopping worker thread...")
-        self.__worker.stop()
+        if self.__worker is not None:
+            self.__worker.stop()
+            self.__worker = None