Improve ability to debug one time listeners blocking the event loop (#110064)

homeassistant/core.py

@@ -22,6 +22,7 @@ from dataclasses import dataclass
 import datetime
 import enum
 import functools
+import inspect
 import logging
 import os
 import pathlib
@@ -1158,7 +1159,7 @@ class _OneTimeListener:
     remove: CALLBACK_TYPE | None = None
 
     @callback
-    def async_call(self, event: Event) -> None:
+    def __call__(self, event: Event) -> None:
         """Remove listener from event bus and then fire listener."""
         if not self.remove:
             # If the listener was already removed, we don't need to do anything
@@ -1167,6 +1168,13 @@ class _OneTimeListener:
         self.remove = None
         self.hass.async_run_job(self.listener, event)
 
+    def __repr__(self) -> str:
+        """Return the representation of the listener and source module."""
+        module = inspect.getmodule(self.listener)
+        if module:
+            return f"<_OneTimeListener {module.__name__}:{self.listener}>"
+        return f"<_OneTimeListener {self.listener}>"
+
 
 class EventBus:
     """Allow the firing of and listening for events."""
@@ -1364,7 +1372,7 @@ class EventBus:
             event_type,
             (
                 HassJob(
-                    one_time_listener.async_call,
+                    one_time_listener,
                     f"onetime listen {event_type} {listener}",
                     job_type=HassJobType.Callback,
                 ),

tests/test_core.py

@@ -2818,3 +2818,16 @@ def test_deprecated_constants(
 ) -> None:
     """Test deprecated constants."""
     import_and_test_deprecated_constant_enum(caplog, ha, enum, "SOURCE_", "2025.1")
+
+
+def test_one_time_listener_repr(hass: HomeAssistant) -> None:
+    """Test one time listener repr."""
+
+    def _listener(event: ha.Event):
+        """Test listener."""
+
+    one_time_listener = ha._OneTimeListener(hass, _listener)
+    repr_str = repr(one_time_listener)
+    assert "OneTimeListener" in repr_str
+    assert "test_core" in repr_str
+    assert "_listener" in repr_str