ignore callback removal is process already closed

aiidateam · Feb 1, 2021 · 4d5f1a5 · 4d5f1a5
1 parent bfa4011
commit 4d5f1a5
Showing 1 changed file with 3 additions and 0 deletions.
diff --git a/plumpy/base/state_machine.py b/plumpy/base/state_machine.py
@@ -286,6 +286,9 @@ def add_state_event_callback(self, hook: Hashable, callback: EVENT_CALLBACK_TYPE
         self._event_callbacks.setdefault(hook, []).append(callback)
 
     def remove_state_event_callback(self, hook: Hashable, callback: EVENT_CALLBACK_TYPE) -> None:
+        if getattr(self, '_closed', False):
+            # if the process is closed, then all callbacks have already been removed
+            return None
         try:
             self._event_callbacks[hook].remove(callback)
         except (KeyError, ValueError):