fix: avoid RuntimeError when a callback unregisters during firing

src/aiousbwatcher/impl.py

@@ -102,7 +102,7 @@ def _async_unregister_callback(self, callback: Callable[[], None]) -> None:
         self._callbacks.remove(callback)
 
     def _async_call_callbacks(self) -> None:
-        for callback in self._callbacks:
+        for callback in list(self._callbacks):
             try:
                 callback()
             except Exception as e:

tests/test_impl.py

@@ -80,6 +80,26 @@ def broken_callback() -> None:
         assert not called
 
 
+@pytest.mark.asyncio
+async def test_aiousbwatcher_callback_unregisters_during_fire() -> None:
+    watcher = AIOUSBWatcher()
+    fired: list[str] = []
+
+    def first() -> None:
+        fired.append("first")
+        unregister_first()
+
+    def second() -> None:
+        fired.append("second")
+
+    unregister_first = watcher.async_register_callback(first)
+    watcher.async_register_callback(second)
+
+    watcher._async_call_callbacks()
+
+    assert sorted(fired) == ["first", "second"]
+
+
 @pytest.mark.asyncio
 @pytest.mark.skipif(
     platform != "linux", reason="Inotify not available on this platform"