Traceback when stopping tool execution

[PiispaH]

Starting and manually stopping tool execution with the script:

produces the following traceback:

AttributeError: 'NoneType' object has no attribute 'returncode'
Traceback (most recent call last):
  File "C:\spine-toolbox\spinetoolbox\ui_main.py", line 2182, in _stop_execution
    self._project.stop()
  File "C:\spine-toolbox\spinetoolbox\project.py", line 1211, in stop
    worker.stop_engine()
  File "C:\spine-toolbox\spinetoolbox\spine_engine_worker.py", line 167, in stop_engine
    self._engine_mngr.stop_engine()
  File "C:\spine-toolbox\spinetoolbox\spine_engine_manager.py", line 158, in stop_engine
    self._engine.stop()
  File "C:\toolbox\src\spine-engine\spine_engine\spine_engine.py", line 350, in stop
    self._stop_item(item)
  File "C:\toolbox\src\spine-engine\spine_engine\spine_engine.py", line 355, in _stop_item
    item.stop_execution()
  File "C:\toolbox\src\spine-items\spine_items\tool\executable_item.py", line 148, in stop_execution
    self._tool_instance.terminate_instance()
  File "C:\toolbox\src\spine-items\spine_items\tool\tool_instance.py", line 70, in terminate_instance
    self.exec_mngr.stop_execution()
  File "C:\toolbox\src\spine-engine\spine_engine\execution_managers\persistent_execution_manager.py", line 848, in stop_execution
    self._persistent_manager.interrupt_persistent()
  File "C:\toolbox\src\spine-engine\spine_engine\execution_managers\persistent_execution_manager.py", line 415, in interrupt_persistent
    self._wait()
  File "C:\toolbox\src\spine-engine\spine_engine\execution_managers\persistent_execution_manager.py", line 287, in _wait
    success = self._persistent.returncode == 0
AttributeError: 'NoneType' object has no attribute 'returncode'