Use explicit exceptions when cancelling listeners

Author: puddly

tests/api/test_listeners.py

@@ -6,6 +6,7 @@
 import zigpy_znp.types as t
 import zigpy_znp.commands as c
 from zigpy_znp.api import OneShotResponseListener, CallbackResponseListener
+from zigpy_znp.exceptions import ShuttingDown
 
 
 async def test_resolve(event_loop, mocker):
@@ -34,24 +35,24 @@ async def test_resolve(event_loop, mocker):
     assert (await future) == match
 
     # Cancelling a callback will have no effect
-    assert not callback_listener.cancel()
+    callback_listener.set_exception(RuntimeError())
 
     # Cancelling a one-shot listener does not throw any errors
-    assert one_shot_listener.cancel()
-    assert one_shot_listener.cancel()
-    assert one_shot_listener.cancel()
+    one_shot_listener.set_exception(RuntimeError())
+    one_shot_listener.set_exception(RuntimeError())
+    one_shot_listener.set_exception(RuntimeError())
 
 
 async def test_cancel(event_loop):
     # Cancelling a one-shot listener prevents it from being fired
     future = event_loop.create_future()
     one_shot_listener = OneShotResponseListener([c.SYS.Ping.Rsp(partial=True)], future)
-    one_shot_listener.cancel()
+    one_shot_listener.set_exception(RuntimeError())
 
     match = c.SYS.Ping.Rsp(Capabilities=t.MTCapabilities.SYS)
     assert not one_shot_listener.resolve(match)
 
-    with pytest.raises(asyncio.CancelledError):
+    with pytest.raises(RuntimeError):
         await future
 
 
@@ -95,7 +96,7 @@ async def test_api_cancel_listeners(connected_znp, mocker):
     assert not future.done()
     znp.close()
 
-    with pytest.raises(asyncio.CancelledError):
+    with pytest.raises(ShuttingDown):
         await future
 
     # add_done_callback won't be executed immediately

zigpy_znp/api.py

@@ -32,7 +32,11 @@
     CallbackResponseListener,
 )
 from zigpy_znp.frames import GeneralFrame
-from zigpy_znp.exceptions import CommandNotRecognized, InvalidCommandResponse
+from zigpy_znp.exceptions import (
+    ShuttingDown,
+    CommandNotRecognized,
+    InvalidCommandResponse,
+)
 from zigpy_znp.types.nvids import ExNvIds, OsalNvIds
 
 if typing.TYPE_CHECKING:
@@ -774,7 +778,7 @@ def close(self) -> None:
 
         for _header, listeners in self._listeners.items():
             for listener in listeners:
-                listener.cancel()
+                listener.set_exception(ShuttingDown())
 
         self._listeners.clear()
         self.version = None

zigpy_znp/exceptions.py

@@ -1,4 +1,4 @@
-from zigpy.exceptions import DeliveryError
+from zigpy.exceptions import DeliveryError, ControllerException
 
 
 class InvalidFrame(ValueError):
@@ -17,3 +17,7 @@ class InvalidCommandResponse(DeliveryError):
     def __init__(self, message, response):
         super().__init__(message)
         self.response = response
+
+
+class ShuttingDown(ControllerException):
+    pass

zigpy_znp/utils.py

@@ -86,7 +86,7 @@ def _resolve(self, response: t.CommandBase) -> bool:
 
         raise NotImplementedError()  # pragma: no cover
 
-    def cancel(self):
+    def set_exception(self, exc: BaseException) -> None:
         """
         Implement by subclasses to cancel the listener.
 
@@ -118,11 +118,9 @@ def _resolve(self, response: t.CommandBase) -> bool:
         self.future.set_result(response)
         return True
 
-    def cancel(self):
+    def set_exception(self, exc: BaseException) -> None:
         if not self.future.done():
-            self.future.cancel()
-
-        return True
+            self.future.set_exception(exc)
 
 
 @dataclasses.dataclass(frozen=True)
@@ -149,9 +147,9 @@ def _resolve(self, response: t.CommandBase) -> bool:
         # Callbacks are always resolved
         return True
 
-    def cancel(self):
+    def set_exception(self, exc: BaseException) -> None:
         # You can't cancel a callback
-        return False
+        pass
 
 
 class CatchAllResponse: