Can you not use an inherited __table__ wrapped with declared_attr from a base class in 2.x?

[trogers-medasync]

I'm upgrading our models from 1.4 to 2.0 and it mostly has gone smoothly. However we have several models that represent views in our db mapped using a hybrid declarative style. These view models inherit a __table__ attribute from a base class that has a __table__ declared as a declared_attr function. After upgrading to 2.0, an error is thrown saying the models don't have a __tablename__ or __table__ defined. Is this not supported anymore? I dug through the source for the declarative process and it seems it explicitly skips inheriting a __table__ and only looks for it in the class's __dict__.

For extra context, the base class's __table__ declared_attr function constructs and returns table object from a sqlalchemy query using sqlalchemy-utils's create_view() function. The query is provided by the individual subclass like so:

reg = registry()

class ViewBase(DeclarativeBase):
    registry = reg

    @classmethod
    def _get_query(cls):
        raise NotImplementedError("")

    @declared_attr
    def __table__(cls) :
        return create_view(cls.__name__, cls.get_query(), cls.registry.metadata)

class ViewInDb(ViewBase):
    @classmethod
    def _get_query(cls):
        return select(TableInDb.col_a, TableInDb.col_b).where(TableInDb.col_a == "foo")

This code was working in 1.4 but after upgrading to 2.0 gives me the above mentioned error complaining that ViewInDb doesn't have a __tablename__ nor a __table__ defined. I wasn't sure if this was a bug or not since I don't see anything in the change log talking about this change, and the docs don't make it clear whether you can or cannot do this.

[zzzeek]

After upgrading to 2.0, an error is thrown saying the models don't have a tablename or table defined. Is this not supported anymore?

this is supported. The behavior is a bug #11509 which will be fixed by tonight. Place __table__ on a subclass of ViewBase declared with __abstract__ = True for now.

[zzzeek]

abstract seems not not work either. you might be able to get away with __table_cls__()

[trogers-medasync]

Thanks for the quick response! I tried the __table_cls__() way but that gave me the same error as above. I ended up working around it using __init_subclass__() on the base class to set cls.__table__ before calling the DeclarativeBase's __init_subclass__().

You said it will be fixed by tonight. Does that mean it will be fixed with a new version in pypi tonight or just fixed in the codebase tonight but deployed to pypi at a later time? If the latter, do you have any idea when that deploy will happen?

[zzzeek]

it means there's a fix in review that will be in the next release, we're due for next release so should be this week.

you can assign __table__ directly on each subclass to work around:

from __future__ import annotations

from sqlalchemy import Column, select
from sqlalchemy import Integer
from sqlalchemy import Table
from sqlalchemy.orm import DeclarativeBase
from sqlalchemy.orm import declared_attr


class BaseWithTable(DeclarativeBase):

    def _make_a_table(cls):
        return Table(
            cls.__name__,
            cls.registry.metadata,
            Column("id", Integer, primary_key=True),
        )


class HasTable(BaseWithTable):
    __table__ = declared_attr(BaseWithTable._make_a_table)


class AlsoHasATable(BaseWithTable):
    __table__ = declared_attr(BaseWithTable._make_a_table)


print(select(HasTable))