Fix infinite loop in actor decorator for finished actors

Previously, the actor decorator was causing an infinite loop
for actors that had finished normally (without exceptions)
even when the restart_limit attribute was set to zero.
This was particularly problematic in test cases where the
restart_limit attribute was intended to limit the number of
times an actor can be restarted.

To address this issue, the patch modified the code to consider
the restart_limit attribute in cases where exceptions different
than CancelledError are raised or when an actor finishes normally.
This ensures that the actor decorator does not cause an infinite
loop for finished actors, and the restart_limit attribute works
as expected.

Signed-off-by: Daniel Zullo <[email protected]>

Author: daniel-zullo-frequenz

src/frequenz/sdk/actor/_decorator.py

@@ -201,23 +201,23 @@ async def _start_actor(self) -> None:
             """
             logger.debug("Starting actor: %s", cls.__name__)
             number_of_restarts = 0
-            while True:
+            while (
+                self.restart_limit is None or number_of_restarts <= self.restart_limit
+            ):
+                if number_of_restarts > 0:
+                    logger.info("Restarting actor: %s", cls.__name__)
+
                 try:
                     await super().run()
                 except asyncio.CancelledError:
                     logger.debug("Cancelling actor: %s", cls.__name__)
                     raise
                 except Exception:  # pylint: disable=broad-except
                     logger.exception("Actor (%s) crashed", cls.__name__)
-                    if (
-                        self.restart_limit is None
-                        or number_of_restarts < self.restart_limit
-                    ):
-                        number_of_restarts += 1
-                        logger.info("Restarting actor: %s", cls.__name__)
-                    else:
-                        logger.info("Shutting down actor: %s", cls.__name__)
-                        break
+                finally:
+                    number_of_restarts += 1
+
+            logger.info("Shutting down actor: %s", cls.__name__)
 
         async def _stop(self) -> None:
             """Stop an running actor."""