[Sqlalchemy-tickets] Issue #3285: an exception which occurs when forming row processors in loading.py leaves the cursor open (zzzeek/sqlalchemy)

[Mike B. <iss...@bi...>]

New issue 3285: an exception which occurs when forming row processors in loading.py leaves the cursor open
https://bitbucket.org/zzzeek/sqlalchemy/issue/3285/an-exception-which-occurs-when-forming-row

Mike Bayer:

e.g. such as this:


```
#!

test/orm/test_eager_relations.py::EagerTest::test_disable_dynamic FAILED

===================================================== FAILURES ======================================================
__________________________________________ EagerTest.test_disable_dynamic ___________________________________________
Traceback (most recent call last):
  File "/home/mbayer/dev/sqlalchemy/test/orm/test_eager_relations.py", line 433, in test_disable_dynamic
    sess.query(User).options(joinedload(User.addresses)).first()
  File "/home/mbayer/dev/sqlalchemy/test/../lib/sqlalchemy/orm/query.py", line 2447, in first
    ret = list(self[0:1])
  File "/home/mbayer/dev/sqlalchemy/test/../lib/sqlalchemy/orm/query.py", line 2283, in __getitem__
    return list(res)
  File "/home/mbayer/dev/sqlalchemy/test/../lib/sqlalchemy/orm/loading.py", line 50, in instances
    for query_entity in query._entities
  File "/home/mbayer/dev/sqlalchemy/test/../lib/sqlalchemy/orm/query.py", line 3280, in row_processor
    polymorphic_discriminator=self._polymorphic_discriminator
  File "/home/mbayer/dev/sqlalchemy/test/../lib/sqlalchemy/orm/loading.py", line 249, in instance_processor
    context, path, mapper, result, adapter, populators)
  File "/home/mbayer/dev/sqlalchemy/test/../lib/sqlalchemy/orm/interfaces.py", line 477, in create_row_processor
    mapper, result, adapter, populators)
  File "/home/mbayer/dev/sqlalchemy/test/../lib/sqlalchemy/orm/strategies.py", line 1442, in create_row_processor
    self
InvalidRequestError: 'User.addresses' does not support object population - eager loading cannot be applied.
```

in that test, if we just swallow the error, the cursor stays open, and pypy gets screwed up; even closing the connection it keeps the table locked.