Fix ConfigManagingActor crashing when any file was deleted

`event.path.samefile` raises error if:
 * `event.pathq` doesn't exists
 * path `p` doesn't exists
In this case it raised exception:
 * if any file in parent directory was deleted
 * any path in self._config_paths didn't exist

Signed-off-by: Elzbieta Kotulska <[email protected]>

Author: ela-kotulska-frequenz

src/frequenz/sdk/config/_config_managing.py

@@ -193,7 +193,16 @@ async def _run(self) -> None:
             # Since we are watching the whole parent directories, we need to make
             # sure we only react to events related to the configuration files we
             # are interested in.
-            if not any(event.path.samefile(p) for p in self._config_paths):
+            #
+            # pathlib.Path.samefile raises error if any path doesn't exist so we need to
+            # make sure `event.path` and `p` exists before calling it.
+            #
+            # On EventType.DELETE event the event.path won't exists and we have no way
+            # to check if this path is in self._config_paths so we need to skip this
+            # event.
+            if not event.path.exists() or not any(
+                event.path.samefile(p) for p in self._config_paths if p.exists()
+            ):
                 continue
 
             match event.type:
@@ -212,10 +221,10 @@ async def _run(self) -> None:
                     )
                     await self.send_config()
                 case EventType.DELETE:
-                    _logger.info(
-                        "%s: The configuration file %s was deleted, ignoring...",
-                        self,
-                        event.path,
+                    # Deletion should be handled in the if statement above by checking
+                    # if event.path exists.
+                    raise RuntimeError(
+                        "DELETE event should be handled in the if statement above"
                     )
                 case _:
                     assert_never(event.type)