[Sqlalchemy-tickets] Issue #3823: Column default raises AttributeError when it takes a callable without __module__ attribute (zzzeek/sqlalchemy)

[Hong M. <iss...@bi...>]

New issue 3823: Column default raises AttributeError when it takes a callable without __module__ attribute
https://bitbucket.org/zzzeek/sqlalchemy/issues/3823/column-default-raises-attributeerror-when

Hong Minhee:

Since SQLAlchemy 1.1, `Column` raises `AttributeError` when its `default` option takes a callable having no `__module__` attribute.  The following example code had worked until SQLAlchemy 1.1:

```python
created_at = Column(
    DateTime(timezone=True),
    default=functools.partial(datetime.datetime.now, datetime.timezone.utc)
)
```

The following traceback is from SQLAlchemy 1.1.0 (and I checked the same error on 1.1.1 as well):

```pytb
Traceback (most recent call last):
  File "/.../ads/ad.py", line 112, in <module>
    class AdRevision(Base):
  File "/.../ads/ad.py", line 120, in AdRevision
    default=functools.partial(datetime.datetime.now, datetime.timezone.utc)
  File "/.../.env/lib/python3.5/site-packages/sqlalchemy/sql/schema.py", line 1210, in __init__
    args.append(ColumnDefault(self.default))
  File "/.../.env/lib/python3.5/site-packages/sqlalchemy/sql/schema.py", line 2016, in __init__
    arg = self._maybe_wrap_callable(arg)
  File "/.../.env/lib/python3.5/site-packages/sqlalchemy/sql/schema.py", line 2043, in _maybe_wrap_callable
    return util.wrap_callable(lambda ctx: fn(), fn)
  File "/.../.env/lib/python3.5/site-packages/sqlalchemy/util/langhelpers.py", line 1401, in wrap_callable
    _f.__module__ = fn.__module__
AttributeError: 'functools.partial' object has no attribute '__module__'
```