exception in worker when running integration tests

[wilko77]

The tests itself pass, but in the logs of the worker, we can find this:

encoding_worker_1   | During handling of the above exception, another exception occurred:
encoding_worker_1   | 
encoding_worker_1   | Traceback (most recent call last):
encoding_worker_1   |   File "/usr/lib/python3.8/site-packages/celery/app/trace.py", line 385, in trace_task
encoding_worker_1   |     R = retval = fun(*args, **kwargs)
encoding_worker_1   |   File "/usr/lib/python3.8/site-packages/celery/app/trace.py", line 650, in __protected_call__
encoding_worker_1   |     return self.run(*args, **kwargs)
encoding_worker_1   |   File "/var/www/clkhash_worker.py", line 119, in hash
encoding_worker_1   |     db_session.query(Clk).filter(
encoding_worker_1   |   File "/usr/lib/python3.8/site-packages/sqlalchemy/orm/query.py", line 4031, in update
encoding_worker_1   |     update_op.exec_()
encoding_worker_1   |   File "/usr/lib/python3.8/site-packages/sqlalchemy/orm/persistence.py", line 1696, in exec_
encoding_worker_1   |     self._do_pre_synchronize()
encoding_worker_1   |   File "/usr/lib/python3.8/site-packages/sqlalchemy/orm/persistence.py", line 1782, in _do_pre_synchronize
encoding_worker_1   |     self.matched_objects = [
encoding_worker_1   |   File "/usr/lib/python3.8/site-packages/sqlalchemy/orm/persistence.py", line 1789, in <listcomp>
encoding_worker_1   |     if issubclass(cls, target_cls) and eval_condition(obj)
encoding_worker_1   |   File "/usr/lib/python3.8/site-packages/sqlalchemy/orm/evaluator.py", line 126, in evaluate
encoding_worker_1   |     value = sub_evaluate(obj)
encoding_worker_1   |   File "/usr/lib/python3.8/site-packages/sqlalchemy/orm/evaluator.py", line 126, in evaluate
encoding_worker_1   |     value = sub_evaluate(obj)
encoding_worker_1   |   File "/usr/lib/python3.8/site-packages/sqlalchemy/orm/evaluator.py", line 158, in evaluate
encoding_worker_1   |     left_val = eval_left(obj)
encoding_worker_1   |   File "/usr/lib/python3.8/site-packages/sqlalchemy/orm/evaluator.py", line 105, in <lambda>
encoding_worker_1   |     return lambda obj: get_corresponding_attr(obj)
encoding_worker_1   |   File "/usr/lib/python3.8/site-packages/sqlalchemy/orm/attributes.py", line 287, in __get__
encoding_worker_1   |     return self.impl.get(instance_state(instance), dict_)
encoding_worker_1   |   File "/usr/lib/python3.8/site-packages/sqlalchemy/orm/attributes.py", line 718, in get
encoding_worker_1   |     value = state._load_expired(state, passive)
encoding_worker_1   |   File "/usr/lib/python3.8/site-packages/sqlalchemy/orm/state.py", line 652, in _load_expired
encoding_worker_1   |     self.manager.deferred_scalar_loader(self, toload)
encoding_worker_1   |   File "/usr/lib/python3.8/site-packages/sqlalchemy/orm/loading.py", line 1008, in load_scalar_attributes
encoding_worker_1   |     result = load_on_ident(
encoding_worker_1   |   File "/usr/lib/python3.8/site-packages/sqlalchemy/orm/loading.py", line 201, in load_on_ident
encoding_worker_1   |     return load_on_pk_identity(
encoding_worker_1   |   File "/usr/lib/python3.8/site-packages/sqlalchemy/orm/loading.py", line 287, in load_on_pk_identity
encoding_worker_1   |     return q.one()
encoding_worker_1   |   File "/usr/lib/python3.8/site-packages/sqlalchemy/orm/query.py", line 3458, in one
encoding_worker_1   |     ret = self.one_or_none()
encoding_worker_1   |   File "/usr/lib/python3.8/site-packages/sqlalchemy/orm/query.py", line 3427, in one_or_none
encoding_worker_1   |     ret = list(self)
encoding_worker_1   |   File "/usr/lib/python3.8/site-packages/sqlalchemy/orm/query.py", line 3503, in __iter__
encoding_worker_1   |     return self._execute_and_instances(context)
encoding_worker_1   |   File "/usr/lib/python3.8/site-packages/sqlalchemy/orm/query.py", line 3524, in _execute_and_instances
encoding_worker_1   |     conn = self._get_bind_args(
encoding_worker_1   |   File "/usr/lib/python3.8/site-packages/sqlalchemy/orm/query.py", line 3539, in _get_bind_args
encoding_worker_1   |     return fn(
encoding_worker_1   |   File "/usr/lib/python3.8/site-packages/sqlalchemy/orm/query.py", line 3518, in _connection_from_session
encoding_worker_1   |     conn = self.session.connection(**kw)
encoding_worker_1   |   File "/usr/lib/python3.8/site-packages/sqlalchemy/orm/session.py", line 1138, in connection
encoding_worker_1   |     return self._connection_for_bind(
encoding_worker_1   |   File "/usr/lib/python3.8/site-packages/sqlalchemy/orm/session.py", line 1146, in _connection_for_bind
encoding_worker_1   |     return self.transaction._connection_for_bind(
encoding_worker_1   |   File "/usr/lib/python3.8/site-packages/sqlalchemy/orm/session.py", line 409, in _connection_for_bind
encoding_worker_1   |     self._assert_active()
encoding_worker_1   |   File "/usr/lib/python3.8/site-packages/sqlalchemy/orm/session.py", line 289, in _assert_active
encoding_worker_1   |     raise sa_exc.InvalidRequestError(
encoding_worker_1   | sqlalchemy.exc.InvalidRequestError: This Session's transaction has been rolled back due to a previous exception during flush. To begin a new transaction with this Session, first issue Session.rollback(). Original exception was: UPDATE statement on table 'clks' expected to update 1000 row(s); 0 were matched. (Background on this error at: http://sqlalche.me/e/13/7s2a)

[wilko77]

hm... I tried again (rebuild, rerun), this time no exception. Weird...