Hi folks,
While running my test suite, I hit an issue with the following stack trace:
ERROR at setup of test_track_before_delete
request = <SubRequest 'database_session' for <Function
'test_track_before_delete'>>, engine = Engine(sqlite:///test.db)
@pytest.fixture
def database_session(request, engine):
connection = engine.connect()
trans = connection.begin()
meta.Session = scoped_session(sessionmaker(autocommit=False,
autoflush=True, bind=connection))
register_session_listeners(meta.Session)
meta.Session.begin_nested()
> @event.listens_for(meta.Session, "after_transaction_end")
def restart_savepoint(session, transaction):
if transaction.nested and not transaction._parent.nested:
automated_tests/conftest.py:52:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
../../../.virtualenvs/ERP/lib/python2.7/site-packages/sqlalchemy/event/api.
py:94: in decorate
listen(target, identifier, fn, *args, **kw)
../../../.virtualenvs/ERP/lib/python2.7/site-packages/sqlalchemy/event/api.
py:63: in listen
_event_key(target, identifier, fn).listen(*args, **kw)
../../../.virtualenvs/ERP/lib/python2.7/site-packages/sqlalchemy/event/
registry.py:187: in listen
self.dispatch_target.dispatch._listen(self, *args, **kw)
../../../.virtualenvs/ERP/lib/python2.7/site-packages/sqlalchemy/event/base.
py:184: in _listen
event_key.base_listen(propagate=propagate, insert=insert, named=named)
../../../.virtualenvs/ERP/lib/python2.7/site-packages/sqlalchemy/event/
registry.py:226: in base_listen
for_modify(target.dispatch).append(self, propagate)
../../../.virtualenvs/ERP/lib/python2.7/site-packages/sqlalchemy/event/attr.
py:118: in append
registry._stored_in_collection(event_key, self)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
event_key = <sqlalchemy.event.registry._EventKey object at 0x111c6b3d0>,
owner = <sqlalchemy.event.attr._DispatchDescriptor object at 0x10eac8590>
def _stored_in_collection(event_key, owner):
key = event_key._key
dispatch_reg = _key_to_collection[key]
owner_ref = owner.ref
listen_ref = weakref.ref(event_key._listen_fn)
if owner_ref in dispatch_reg:
> assert dispatch_reg[owner_ref] == listen_ref
E assert <weakref at 0x111cc25d0; dead> == <weakref at 0x111cc2af8
; to 'function' at 0x111c7f668 (restart_savepoint)>
../../../.virtualenvs/ERP/lib/python2.7/site-packages/sqlalchemy/event/
registry.py:74: AssertionError
While running the @event.listens_for decorator in the setup of a test
fixture, SQLAlchemy throws an assertion because the ref it has in the
dispatch registry isn't identical to the ref to the listener function.
We're on SQLAlchemy 0.9.7, pytest 2.6.4. Note that the test suite is
setting up nested transactions on SQLite; we are using the recommended
workaround from SQLAlchemy documentation to take control of transactional
integration from pysqlite.
Since there's an assertion in the code in _stored_in_collection(), I assume
that there's some expectation that the refs might not match; am I doing
something wrong in my setup which this assertion is meant to catch? I've
only seen this error once (while tracking down a different nondeterministic
error in my own app's code), so I can't provide much more information than
this, but the portion of test fixture code seen above in the stack trace is
basically the entire reproduction case. This fixture runs before every
test in my suite, but I've only seen an error once across a large number of
runs, so the error is *very* intermittent. Because of that, I'm not
worried too much about the error itself, but I thought I should post it
here in case it's a symptom of something I should be worrying about.
Thanks,
Evan James
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