Stop using chess.engine.EventLoopPolicy

niklasf · Jul 27, 2023 · 7acc7cf · 7acc7cf
1 parent 8214d97
commit 7acc7cf
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Showing 5 changed files with 2 additions and 103 deletions.
diff --git a/chess/engine.py b/chess/engine.py
@@ -42,77 +42,8 @@
 MANAGED_OPTIONS = ["uci_chess960", "uci_variant", "multipv", "ponder"]
 
 
-class EventLoopPolicy(asyncio.AbstractEventLoopPolicy):
-    """
-    An event loop policy for thread-local event loops and child watchers.
-    Ensures each event loop is capable of spawning and watching subprocesses,
-    even when not running on the main thread.
-
-    Windows: Uses :class:`~asyncio.ProactorEventLoop`.
-
-    Unix: Uses :class:`~asyncio.SelectorEventLoop`. If available,
-    :class:`~asyncio.PidfdChildWatcher` is used to detect subprocess
-    termination (Python 3.9+ on Linux 5.3+). Otherwise, the default child
-    watcher is used on the main thread and relatively slow eager polling
-    is used on all other threads.
-    """
-    class _Local(threading.local):
-        loop: Optional[asyncio.AbstractEventLoop] = None
-        set_called = False
-        watcher: Optional[asyncio.AbstractChildWatcher] = None
-
-    def __init__(self) -> None:
-        self._local = self._Local()
-
-    def get_event_loop(self) -> asyncio.AbstractEventLoop:
-        if self._local.loop is None and not self._local.set_called and threading.current_thread() is threading.main_thread():
-            self.set_event_loop(self.new_event_loop())
-        if self._local.loop is None:
-            raise RuntimeError(f"no current event loop in thread {threading.current_thread().name!r}")
-        return self._local.loop
-
-    def set_event_loop(self, loop: Optional[asyncio.AbstractEventLoop]) -> None:
-        assert loop is None or isinstance(loop, asyncio.AbstractEventLoop)
-        self._local.set_called = True
-        self._local.loop = loop
-        if self._local.watcher is not None:
-            self._local.watcher.attach_loop(loop)
-
-    def new_event_loop(self) -> asyncio.AbstractEventLoop:
-        return asyncio.ProactorEventLoop() if sys.platform == "win32" else asyncio.SelectorEventLoop()  # type: ignore
-
-    def get_child_watcher(self) -> asyncio.AbstractChildWatcher:
-        if self._local.watcher is None:
-            self._local.watcher = self._init_watcher()
-            self._local.watcher.attach_loop(self._local.loop)
-        return self._local.watcher
-
-    def set_child_watcher(self, watcher: Optional[asyncio.AbstractChildWatcher]) -> None:
-        assert watcher is None or isinstance(watcher, asyncio.AbstractChildWatcher)
-        if self._local.watcher is not None:
-            self._local.watcher.close()
-        self._local.watcher = watcher
-
-    def _init_watcher(self) -> asyncio.AbstractChildWatcher:
-        if sys.platform == "win32":
-            raise NotImplementedError
-
-        try:
-            os.close(os.pidfd_open(os.getpid()))
-            watcher: asyncio.AbstractChildWatcher = asyncio.PidfdChildWatcher()
-            LOGGER.debug("Using PidfdChildWatcher")
-            return watcher
-        except (AttributeError, OSError):
-            # Before Python 3.9 or before Linux 5.3 or the syscall is not
-            # permitted.
-            pass
-
-        if threading.current_thread() is threading.main_thread():
-            LOGGER.debug("Using SafeChildWatcher")
-            return asyncio.SafeChildWatcher()
-        else:
-            LOGGER.debug("Using ThreadedChildWatcher")
-            return asyncio.ThreadedChildWatcher()
+# No longer needed, but alias kept around for compatibility.
+EventLoopPolicy = asyncio.DefaultEventLoopPolicy
 
 
 def run_in_background(coroutine: Callable[[concurrent.futures.Future[T]], Coroutine[Any, Any, None]], *, name: Optional[str] = None, debug: bool = False, _policy_lock: threading.Lock = threading.Lock()) -> T:
@@ -122,16 +53,9 @@ def run_in_background(coroutine: Callable[[concurrent.futures.Future[T]], Corout
     Blocks on *future* and returns the result as soon as it is resolved.
     The coroutine and all remaining tasks continue running in the background
     until complete.
-
-    Note: This installs a :class:`chess.engine.EventLoopPolicy` for the entire
-    process.
     """
     assert asyncio.iscoroutinefunction(coroutine)
 
-    with _policy_lock:
-        if not isinstance(asyncio.get_event_loop_policy(), EventLoopPolicy):
-            asyncio.set_event_loop_policy(EventLoopPolicy())
-
     future: concurrent.futures.Future[T] = concurrent.futures.Future()
 
     def background() -> None:

diff --git a/docs/engine.rst b/docs/engine.rst
@@ -58,7 +58,6 @@ Example: Let Stockfish play against itself, 100 milliseconds per move.
 
         await engine.quit()
 
-    asyncio.set_event_loop_policy(chess.engine.EventLoopPolicy())
     asyncio.run(main())
 
 .. autoclass:: chess.engine.Protocol
@@ -126,7 +125,6 @@ Example:
 
         await engine.quit()
 
-    asyncio.set_event_loop_policy(chess.engine.EventLoopPolicy())
     asyncio.run(main())
 
 .. autoclass:: chess.engine.Protocol
@@ -189,7 +187,6 @@ Example: Stream information from the engine and stop on an arbitrary condition.
 
         await engine.quit()
 
-    asyncio.set_event_loop_policy(chess.engine.EventLoopPolicy())
     asyncio.run(main())
 
 .. autoclass:: chess.engine.Protocol
@@ -243,7 +240,6 @@ Options
 
         # [...]
 
-    asyncio.set_event_loop_policy(chess.engine.EventLoopPolicy())
     asyncio.run(main())
 
 .. autoclass:: chess.engine.Protocol
@@ -315,5 +311,3 @@ Reference
 
 .. autoclass:: chess.engine.SimpleAnalysisResult
     :members:
-
-.. autofunction:: chess.engine.EventLoopPolicy
diff --git a/examples/bratko_kopec/bratko_kopec.py b/examples/bratko_kopec/bratko_kopec.py
@@ -152,5 +152,4 @@ async def main() -> None:
 
 
 if __name__ == "__main__":
-    asyncio.set_event_loop_policy(chess.engine.EventLoopPolicy())
     asyncio.run(main())
diff --git a/fuzz/engine.py b/fuzz/engine.py
@@ -7,7 +7,6 @@
 
 
 logging.getLogger("chess.engine").setLevel(logging.CRITICAL)
-asyncio.set_event_loop_policy(chess.engine.EventLoopPolicy())
 
 
 @PythonFuzz

diff --git a/test.py b/test.py
@@ -3114,7 +3114,6 @@ async def main():
             await protocol.ping()
             mock.assert_done()
 
-        asyncio.set_event_loop_policy(chess.engine.EventLoopPolicy())
         asyncio.run(main())
 
     def test_uci_debug(self):
@@ -3130,7 +3129,6 @@ async def main():
             protocol.debug(False)
             mock.assert_done()
 
-        asyncio.set_event_loop_policy(chess.engine.EventLoopPolicy())
         asyncio.run(main())
 
     def test_uci_go(self):
@@ -3173,7 +3171,6 @@ async def main():
             self.assertEqual(result.ponder, None)
             mock.assert_done()
 
-        asyncio.set_event_loop_policy(chess.engine.EventLoopPolicy())
         asyncio.run(main())
 
     def test_iota_log(self):
@@ -3196,7 +3193,6 @@ async def main():
                 await protocol.play(board, chess.engine.Limit(time=5.0))
             mock.assert_done()
 
-        asyncio.set_event_loop_policy(chess.engine.EventLoopPolicy())
         asyncio.run(main())
 
     def test_uci_analyse_mode(self):
@@ -3243,7 +3239,6 @@ async def main():
             self.assertEqual(best.ponder, chess.Move.from_uci("e7e5"))
             mock.assert_done()
 
-        asyncio.set_event_loop_policy(chess.engine.EventLoopPolicy())
         asyncio.run(main())
 
     def test_uci_play_after_analyse(self):
@@ -3271,7 +3266,6 @@ async def main():
 
             mock.assert_done()
 
-        asyncio.set_event_loop_policy(chess.engine.EventLoopPolicy())
         asyncio.run(main())
 
     def test_uci_ponderhit(self):
@@ -3387,7 +3381,6 @@ async def main():
 
             mock.assert_done()
 
-        asyncio.set_event_loop_policy(chess.engine.EventLoopPolicy())
         asyncio.run(main())
 
     def test_uci_info(self):
@@ -3474,7 +3467,6 @@ async def main():
             await protocol.send_game_result(checkmate_board)
             mock.assert_done()
 
-        asyncio.set_event_loop_policy(chess.engine.EventLoopPolicy())
         asyncio.run(main())
 
     def test_hiarcs_bestmove(self):
@@ -3499,7 +3491,6 @@ async def main():
             self.assertEqual(result.info["string"], "keep double  space")
             mock.assert_done()
 
-        asyncio.set_event_loop_policy(chess.engine.EventLoopPolicy())
         asyncio.run(main())
 
     def test_xboard_options(self):
@@ -3562,7 +3553,6 @@ async def main():
             await protocol.configure({"buttonvar": None})
             mock.assert_done()
 
-        asyncio.set_event_loop_policy(chess.engine.EventLoopPolicy())
         asyncio.run(main())
 
     def test_xboard_replay(self):
@@ -3624,7 +3614,6 @@ async def main():
             self.assertEqual(result.move, board.parse_san("d4"))
             mock.assert_done()
 
-        asyncio.set_event_loop_policy(chess.engine.EventLoopPolicy())
         asyncio.run(main())
 
     def test_xboard_opponent(self):
@@ -3682,7 +3671,6 @@ async def main():
                 result = await protocol.play(board, limit, game="bad game", opponent=bad_opponent)
             mock.assert_done()
 
-        asyncio.set_event_loop_policy(chess.engine.EventLoopPolicy())
         asyncio.run(main())
 
     def test_xboard_result(self):
@@ -3772,7 +3760,6 @@ async def main():
             await protocol.send_game_result(material_board)
             mock.assert_done()
 
-        asyncio.set_event_loop_policy(chess.engine.EventLoopPolicy())
         asyncio.run(main())
 
     def test_xboard_analyse(self):
@@ -3810,7 +3797,6 @@ async def main():
             self.assertEqual(info["pv"], [chess.Move.from_uci(move) for move in ["f7f6", "e2e4", "e7e6"]])
             mock.assert_done()
 
-        asyncio.set_event_loop_policy(chess.engine.EventLoopPolicy())
         asyncio.run(main())
 
     def test_xboard_level(self):
@@ -3855,7 +3841,6 @@ async def main():
             self.assertEqual(result.move, chess.Move.from_uci("d2d4"))
             mock.assert_done()
 
-        asyncio.set_event_loop_policy(chess.engine.EventLoopPolicy())
         asyncio.run(main())
 
     def test_xboard_error(self):
@@ -3874,7 +3859,6 @@ async def main():
 
             mock.assert_done()
 
-        asyncio.set_event_loop_policy(chess.engine.EventLoopPolicy())
         asyncio.run(main())
 
     @catchAndSkip(FileNotFoundError, "need /bin/bash")
@@ -3886,7 +3870,6 @@ async def main():
             self.assertNotEqual(results[0], None)
             self.assertNotEqual(results[1], None)
 
-        asyncio.set_event_loop_policy(chess.engine.EventLoopPolicy())
         asyncio.run(main())
 
     @catchAndSkip(FileNotFoundError, "need /bin/bash")