Flask-SQLAlchemy weakref KeyError

[thomaxxl]

Upgrading to Flask-SQLAlchemy>=3.0.0 gives this stacktrace:

  File "/home/lnx/Flask-App/venv/lib/python3.9/site-packages/sqlalchemy/orm/query.py", line 2772, in all
    return self._iter().all()
  File "/home/lnx/Flask-App/venv/lib/python3.9/site-packages/sqlalchemy/orm/query.py", line 2907, in _iter
    result = self.session.execute(
  File "/home/lnx/Flask-App/venv/lib/python3.9/site-packages/sqlalchemy/orm/session.py", line 1702, in execute
    bind = self.get_bind(**bind_arguments)
  File "/home/lnx/Flask-App/venv/lib/python3.9/site-packages/flask_sqlalchemy/session.py", line 61, in get_bind
    engines = self._db.engines
  File "/home/lnx/Flask-App/venv/lib/python3.9/site-packages/flask_sqlalchemy/extension.py", line 629, in engines
    return self._app_engines[app]
  File "/usr/lib/python3.9/weakref.py", line 405, in __getitem__
    return self.data[ref(key)]
KeyError: <weakref at 0x7f1a00f1a6d0; to 'Flask' at 0x7f1a00f16130>

Environment:

• Python version:
  3.8.10, 3.9.5
• Flask-SQLAlchemy version:

=3.0.0

• SQLAlchemy version:
  SQLAlchemy==1.4.42