python · kumaraditya303 · Jun 21, 2024 · Jun 20, 2024 · Jun 20, 2024 · Jun 20, 2024
@@ -28,9 +28,9 @@
 
 __all__ = (
     'SelectorEventLoop',
-    'AbstractChildWatcher', 'SafeChildWatcher',
-    'FastChildWatcher', 'PidfdChildWatcher',
-    'MultiLoopChildWatcher', 'ThreadedChildWatcher',
+    'AbstractChildWatcher',
+    'PidfdChildWatcher',
+    'ThreadedChildWatcher',
     'DefaultEventLoopPolicy',
     'EventLoop',
 )
@@ -1062,325 +1062,6 @@ def _sig_chld(self):
             })
 
 
-class SafeChildWatcher(BaseChildWatcher):
-    """'Safe' child watcher implementation.
-
-    This implementation avoids disrupting other code spawning processes by
-    polling explicitly each process in the SIGCHLD handler instead of calling
-    os.waitpid(-1).
-
-    This is a safe solution but it has a significant overhead when handling a
-    big number of children (O(n) each time SIGCHLD is raised)
-    """
-
-    def __init__(self):
-        super().__init__()
-        warnings._deprecated("SafeChildWatcher",
-                             "{name!r} is deprecated as of Python 3.12 and will be "
-                             "removed in Python {remove}.",
-                              remove=(3, 14))
-
-    def close(self):
-        self._callbacks.clear()
-        super().close()
-
-    def __enter__(self):
-        return self
-
-    def __exit__(self, a, b, c):
-        pass
-
-    def add_child_handler(self, pid, callback, *args):
-        self._callbacks[pid] = (callback, args)
-
-        # Prevent a race condition in case the child is already terminated.
-        self._do_waitpid(pid)
-
-    def remove_child_handler(self, pid):
-        try:
-            del self._callbacks[pid]
-            return True
-        except KeyError:
-            return False
-
-    def _do_waitpid_all(self):
-
-        for pid in list(self._callbacks):
-            self._do_waitpid(pid)
-
-    def _do_waitpid(self, expected_pid):
-        assert expected_pid > 0
-
-        try:
-            pid, status = os.waitpid(expected_pid, os.WNOHANG)
-        except ChildProcessError:
-            # The child process is already reaped
-            # (may happen if waitpid() is called elsewhere).
-            pid = expected_pid
-            returncode = 255
-            logger.warning(
-                "Unknown child process pid %d, will report returncode 255",
-                pid)
-        else:
-            if pid == 0:
-                # The child process is still alive.
-                return
-
-            returncode = waitstatus_to_exitcode(status)
-            if self._loop.get_debug():
-                logger.debug('process %s exited with returncode %s',
-                             expected_pid, returncode)
-
-        try:
-            callback, args = self._callbacks.pop(pid)
-        except KeyError:  # pragma: no cover
-            # May happen if .remove_child_handler() is called
-            # after os.waitpid() returns.
-            if self._loop.get_debug():
-                logger.warning("Child watcher got an unexpected pid: %r",
-                               pid, exc_info=True)
-        else:
-            callback(pid, returncode, *args)
-
-
-class FastChildWatcher(BaseChildWatcher):
-    """'Fast' child watcher implementation.
-
-    This implementation reaps every terminated processes by calling
-    os.waitpid(-1) directly, possibly breaking other code spawning processes
-    and waiting for their termination.
-
-    There is no noticeable overhead when handling a big number of children
-    (O(1) each time a child terminates).
-    """
-    def __init__(self):
-        super().__init__()
-        self._lock = threading.Lock()
-        self._zombies = {}
-        self._forks = 0
-        warnings._deprecated("FastChildWatcher",
-                             "{name!r} is deprecated as of Python 3.12 and will be "
-                             "removed in Python {remove}.",
-                              remove=(3, 14))
-
-    def close(self):
-        self._callbacks.clear()
-        self._zombies.clear()
-        super().close()
-
-    def __enter__(self):
-        with self._lock:
-            self._forks += 1
-
-            return self
-
-    def __exit__(self, a, b, c):
-        with self._lock:
-            self._forks -= 1
-
-            if self._forks or not self._zombies:
-                return
-
-            collateral_victims = str(self._zombies)
-            self._zombies.clear()
-
-        logger.warning(
-            "Caught subprocesses termination from unknown pids: %s",
-            collateral_victims)
-
-    def add_child_handler(self, pid, callback, *args):
-        assert self._forks, "Must use the context manager"
-
-        with self._lock:
-            try:
-                returncode = self._zombies.pop(pid)
-            except KeyError:
-                # The child is running.
-                self._callbacks[pid] = callback, args
-                return
-
-        # The child is dead already. We can fire the callback.
-        callback(pid, returncode, *args)
-
-    def remove_child_handler(self, pid):
-        try:
-            del self._callbacks[pid]
-            return True
-        except KeyError:
-            return False
-
-    def _do_waitpid_all(self):
-        # Because of signal coalescing, we must keep calling waitpid() as
-        # long as we're able to reap a child.
-        while True:
-            try:
-                pid, status = os.waitpid(-1, os.WNOHANG)
-            except ChildProcessError:
-                # No more child processes exist.
-                return
-            else:
-                if pid == 0:
-                    # A child process is still alive.
-                    return
-
-                returncode = waitstatus_to_exitcode(status)
-
-            with self._lock:
-                try:
-                    callback, args = self._callbacks.pop(pid)
-                except KeyError:
-                    # unknown child
-                    if self._forks:
-                        # It may not be registered yet.
-                        self._zombies[pid] = returncode
-                        if self._loop.get_debug():
-                            logger.debug('unknown process %s exited '
-                                         'with returncode %s',
-                                         pid, returncode)
-                        continue
-                    callback = None
-                else:
-                    if self._loop.get_debug():
-                        logger.debug('process %s exited with returncode %s',
-                                     pid, returncode)
-
-            if callback is None:
-                logger.warning(
-                    "Caught subprocess termination from unknown pid: "
-                    "%d -> %d", pid, returncode)
-            else:
-                callback(pid, returncode, *args)
-
-
-class MultiLoopChildWatcher(AbstractChildWatcher):
-    """A watcher that doesn't require running loop in the main thread.
-
-    This implementation registers a SIGCHLD signal handler on
-    instantiation (which may conflict with other code that
-    install own handler for this signal).
-
-    The solution is safe but it has a significant overhead when
-    handling a big number of processes (*O(n)* each time a
-    SIGCHLD is received).
-    """
-
-    # Implementation note:
-    # The class keeps compatibility with AbstractChildWatcher ABC
-    # To achieve this it has empty attach_loop() method
-    # and doesn't accept explicit loop argument
-    # for add_child_handler()/remove_child_handler()
-    # but retrieves the current loop by get_running_loop()
-
-    def __init__(self):
-        self._callbacks = {}
-        self._saved_sighandler = None
-        warnings._deprecated("MultiLoopChildWatcher",
-                             "{name!r} is deprecated as of Python 3.12 and will be "
-                             "removed in Python {remove}.",
-                              remove=(3, 14))
-
-    def is_active(self):
-        return self._saved_sighandler is not None
-
-    def close(self):
-        self._callbacks.clear()
-        if self._saved_sighandler is None:
-            return
-
-        handler = signal.getsignal(signal.SIGCHLD)
-        if handler != self._sig_chld:
-            logger.warning("SIGCHLD handler was changed by outside code")
-        else:
-            signal.signal(signal.SIGCHLD, self._saved_sighandler)
-        self._saved_sighandler = None
-
-    def __enter__(self):
-        return self
-
-    def __exit__(self, exc_type, exc_val, exc_tb):
-        pass
-
-    def add_child_handler(self, pid, callback, *args):
-        loop = events.get_running_loop()
-        self._callbacks[pid] = (loop, callback, args)
-
-        # Prevent a race condition in case the child is already terminated.
-        self._do_waitpid(pid)
-
-    def remove_child_handler(self, pid):
-        try:
-            del self._callbacks[pid]
-            return True
-        except KeyError:
-            return False
-
-    def attach_loop(self, loop):
-        # Don't save the loop but initialize itself if called first time
-        # The reason to do it here is that attach_loop() is called from
-        # unix policy only for the main thread.
-        # Main thread is required for subscription on SIGCHLD signal
-        if self._saved_sighandler is not None:
-            return
-
-        self._saved_sighandler = signal.signal(signal.SIGCHLD, self._sig_chld)
-        if self._saved_sighandler is None:
-            logger.warning("Previous SIGCHLD handler was set by non-Python code, "
-                           "restore to default handler on watcher close.")
-            self._saved_sighandler = signal.SIG_DFL
-
-        # Set SA_RESTART to limit EINTR occurrences.
-        signal.siginterrupt(signal.SIGCHLD, False)
-
-    def _do_waitpid_all(self):
-        for pid in list(self._callbacks):
-            self._do_waitpid(pid)
-
-    def _do_waitpid(self, expected_pid):
-        assert expected_pid > 0
-
-        try:
-            pid, status = os.waitpid(expected_pid, os.WNOHANG)
-        except ChildProcessError:
-            # The child process is already reaped
-            # (may happen if waitpid() is called elsewhere).
-            pid = expected_pid
-            returncode = 255
-            logger.warning(
-                "Unknown child process pid %d, will report returncode 255",
-                pid)
-            debug_log = False
-        else:
-            if pid == 0:
-                # The child process is still alive.
-                return
-
-            returncode = waitstatus_to_exitcode(status)
-            debug_log = True
-        try:
-            loop, callback, args = self._callbacks.pop(pid)
-        except KeyError:  # pragma: no cover
-            # May happen if .remove_child_handler() is called
-            # after os.waitpid() returns.
-            logger.warning("Child watcher got an unexpected pid: %r",
-                           pid, exc_info=True)
-        else:
-            if loop.is_closed():
-                logger.warning("Loop %r that handles pid %r is closed", loop, pid)
-            else:
-                if debug_log and loop.get_debug():
-                    logger.debug('process %s exited with returncode %s',
-                                 expected_pid, returncode)
-                loop.call_soon_threadsafe(callback, pid, returncode, *args)
-
-    def _sig_chld(self, signum, frame):
-        try:
-            self._do_waitpid_all()
-        except (SystemExit, KeyboardInterrupt):
-            raise
-        except BaseException:
-            logger.warning('Unknown exception in SIGCHLD handler', exc_info=True)
-
-
 class ThreadedChildWatcher(AbstractChildWatcher):
     """Threaded child watcher implementation.
 

@@ -2214,7 +2214,7 @@ def setUp(self):
             super().setUp()
             with warnings.catch_warnings():
                 warnings.simplefilter('ignore', DeprecationWarning)
-                watcher = asyncio.SafeChildWatcher()
+                watcher = asyncio.ThreadedChildWatcher()
                 watcher.attach_loop(self.loop)
                 asyncio.set_child_watcher(watcher)
 
@@ -2833,13 +2833,6 @@ def setUp(self):
         self.loop = asyncio.new_event_loop()
         asyncio.set_event_loop(self.loop)
 
-        if sys.platform != 'win32':
-            with warnings.catch_warnings():
-                warnings.simplefilter('ignore', DeprecationWarning)
-                watcher = asyncio.SafeChildWatcher()
-                watcher.attach_loop(self.loop)
-                asyncio.set_child_watcher(watcher)
-
     def tearDown(self):
         try:
             if sys.platform != 'win32':