Avoid unnecessary Task in debouncer (#89370)

homeassistant/helpers/debounce.py

@@ -94,11 +94,6 @@ class Debouncer(Generic[_R_co]):
         """Handle a finished timer."""
         assert self._job is not None
 
-        self._timer_task = None
-
-        if not self._execute_at_end_of_timer:
-            return
-
         self._execute_at_end_of_timer = False
 
         # Locked means a call is in progress. Any call is good, so abort.
@@ -108,7 +103,7 @@ class Debouncer(Generic[_R_co]):
         async with self._execute_lock:
             # Abort if timer got set while we're waiting for the lock.
             if self._timer_task:
-                return  # type: ignore[unreachable]
+                return
 
             try:
                 task = self.hass.async_run_hass_job(self._job)
@@ -117,6 +112,7 @@ class Debouncer(Generic[_R_co]):
             except Exception:  # pylint: disable=broad-except
                 self.logger.exception("Unexpected exception from %s", self.function)
 
+            # Schedule a new timer to prevent new runs during cooldown
             self._schedule_timer()
 
     @callback
@@ -129,12 +125,16 @@ class Debouncer(Generic[_R_co]):
         self._execute_at_end_of_timer = False
 
     @callback
-    def _schedule_timer(self) -> None:
-        """Schedule a timer."""
-        self._timer_task = self.hass.loop.call_later(
-            self.cooldown,
-            lambda: self.hass.async_create_task(
+    def _on_debounce(self) -> None:
+        """Create job task, but only if pending."""
+        self._timer_task = None
+        if self._execute_at_end_of_timer:
+            self.hass.async_create_task(
                 self._handle_timer_finish(),
                 f"debouncer {self._job} finish cooldown={self.cooldown}, immediate={self.immediate}",
-            ),
-        )
+            )
+
+    @callback
+    def _schedule_timer(self) -> None:
+        """Schedule a timer."""
+        self._timer_task = self.hass.loop.call_later(self.cooldown, self._on_debounce)