Comment is added to Component.start when handling DatabaseIsCorrupted

src/tribler/core/components/component.py

@@ -54,6 +54,15 @@ async def start(self):
             if isinstance(e, DatabaseIsCorrupted):
                 # When the database corruption is detected, we should stop the process immediately.
                 # Tribler GUI will restart the process and the database will be recreated.
+
+                # Usually we wrap an exception into ComponentStartupException, and allow
+                # CoreExceptionHandler.unhandled_error_observer to handle it after all components are started,
+                # but in this case we don't do it. The reason is that handling ComponentStartupException
+                # starts the shutting down of Tribler, and due to some obscure reasons it is not possible to
+                # raise any exception, even SystemExit, from CoreExceptionHandler.unhandled_error_observer when
+                # Tribler is shutting down. It looks like in this case unhandled_error_observer is called from
+                # Task.__del__ method and all exceptions that are raised from __del__ are ignored.
+                # See https://bugs.python.org/issue25489 for similar case.
                 process_manager = get_global_process_manager()
                 process_manager.sys_exit(EXITCODE_DATABASE_IS_CORRUPTED, e)
                 return  # Added for clarity; actually, the code raised SystemExit on the previous line