Exception on '.refresh' for certain objects - state.load_path Tuple is empty

[Gmoney]

On python 3.7 SQLAlchemy 1.3.13

I'm running into an issue when doing a session.refresh(orm_object) where for certain objects it throws an exception because in line 709 of orm/loading.py, the 'state.load_path' is an empty tuple.  Attached the relevant snippet of the stack dump below.

This was simple test with no actual changes:  

task = Task.query.filter(blah).one()

session.refresh(task)

Again it works for some, not for others.

Is there was something obvious that might cause this - perhaps I'm misunderstanding how refresh works?  We have numerous relationships on the model that often refer to the same table (multiple 'user_id' fk references).  This hasn't causes us any other issues, but it's worth noting.

I will try to pare down the model to isolate what the cause is, and follow up with a test case if I can.  But wanted to see if it was anything obvious before I dig too deep.

  File "/-/lib/python3.7/site-packages/sqlalchemy/orm/loading.py", line 709, in _populate_full

    elif load_path != state.load_path:

  File "-/lib/python3.7/site-packages/sqlalchemy/orm/path_registry.py", line 63, in __eq__

    return other is not None and self.path == other.path

AttributeError: 'tuple' object has no attribute 'path'

 

[Mike Bayer]

it looks like a bug unless you are manipulating the InstanceState.   I would upgrade to SQLAlchemy 1.3.23 first to make sure it hasn't been fixed.

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[Gmoney]

Looks like that did the trick!  Should have tried that first, but got lazy when conda was resisting my update attempts earlier.

Thank you

[Mike Bayer]

still kind of weird, I am not seeing any issue like this that was fixed, wouldn't mind seeing a reproducer case but no worries.

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