[assignee_no_login] KeyError: 'field_name'

2025-03-17 12:29:37,186 - ERROR - Rule assignee_no_login
Traceback (most recent call last):
  File "/home/rm_bot/bugbot/bugbot/bzcleaner.py", line 856, in run
    self.send_email(date=date)
  File "/home/rm_bot/bugbot/bugbot/bzcleaner.py", line 772, in send_email
    data = self.get_email_data(date)
  File "/home/rm_bot/bugbot/bugbot/bzcleaner.py", line 690, in get_email_data
    bugs = self.get_bugs(date=date)
  File "/home/rm_bot/bugbot/bugbot/rules/assignee_no_login.py", line 64, in get_bugs
    bugs = super().get_bugs(*args, **kwargs)
  File "/home/rm_bot/bugbot/bugbot/bzcleaner.py", line 465, in get_bugs
    ).get_data().wait()
  File "/home/rm_bot/bugbot/venv/lib/python3.10/site-packages/libmozdata/bugzilla.py", line 180, in wait
    self.wait_bugs()
  File "/home/rm_bot/bugbot/venv/lib/python3.10/site-packages/libmozdata/bugzilla.py", line 191, in wait_bugs
    r.result()
  File "/usr/local/lib/python3.10/concurrent/futures/_base.py", line 458, in result
    return self.__get_result()
  File "/usr/local/lib/python3.10/concurrent/futures/_base.py", line 403, in __get_result
    raise self._exception
  File "/usr/local/lib/python3.10/concurrent/futures/thread.py", line 58, in run
    result = self.fn(*self.args, **self.kwargs)
  File "/home/rm_bot/bugbot/venv/lib/python3.10/site-packages/requests/sessions.py", line 589, in request
    resp = self.send(prep, **send_kwargs)
  File "/home/rm_bot/bugbot/venv/lib/python3.10/site-packages/requests/sessions.py", line 710, in send
    r = dispatch_hook("response", hooks, r, **kwargs)
  File "/home/rm_bot/bugbot/venv/lib/python3.10/site-packages/requests/hooks.py", line 30, in dispatch_hook
    _hook_data = hook(hook_data, **kwargs)
  File "/home/rm_bot/bugbot/venv/lib/python3.10/site-packages/libmozdata/bugzilla.py", line 565, in __bugs_cb
    self.bughandler.handle(bug)
  File "/home/rm_bot/bugbot/venv/lib/python3.10/site-packages/libmozdata/handler.py", line 15, in handle
    self.handler(*args)
  File "/home/rm_bot/bugbot/bugbot/bzcleaner.py", line 346, in bughandler
    if self.handle_bug(bug, data) is None:
  File "/home/rm_bot/bugbot/bugbot/rules/assignee_no_login.py", line 152, in handle_bug
    priority_change_date = self.get_priority_change_date(bug)
  File "/home/rm_bot/bugbot/bugbot/rules/assignee_no_login.py", line 140, in get_priority_change_date
    change["field_name"] == "priority"
KeyError: 'field_name'

Start in bugbot/rules/assignee_no_login.py at get_priority_change_date (line 140) and trace the change records passed from handle_bug. Reproduce the assignee_no_login run that reaches this traceback and verify it no longer raises KeyError for the reported input; confirm priority-change handling still completes.