Alembic migration for cross-schema FK

[aholovenko]

Hi everyone!
I have the main schema that I would like to create a migration for and a schema that is cross-referenced by one of the models in the main schema. How can I create it without the full model of an external table, but using a simple stub?
I keep getting an error:

sqlalchemy.exc.NoReferencedTableError: Foreign key associated with column 'my_table.subscription_id' could not find table 'project' with which to generate a foreign key to target column 'id'

Some parts of my code:

from sqlalchemy import Column, Integer, MetaData, Table
from sqlalchemy.orm import DeclarativeBase

metadata = MetaData()

class Base(DeclarativeBase):
    """Base class for all ORM models."""

    metadata = metadata

_external_project_table = Table(
    'project',
    metadata,
    Column('id', Integer, primary_key=True),
    schema='external_schema',
)


class MyTable(Base):
    __tablename__ = 'my_table'
    ....
    subscription_id: Mapped[int] = mapped_column(
        Integer,
        ForeignKey(
            'external_schema.project.id',
            use_alter=True,
        ),
        nullable=False,
        index=True,
    )

    __table_args__ = (
        {'schema': 'main_schema'},
    )
    ...

# include_object/ include_name and configuration part of env.py

def include_object(object, name, type_, reflected, compare_to):
    if type_ == 'table':
        schema = getattr(object, 'schema', None)
        if schema == 'main_schema':
            return True
        if schema == 'external_schema' and name == 'project':
            return True
        return False
    return True

def include_name(name, type_, parent_names):
    if type_ == "schema":
        return name in ['main_schema', 'external_schema']
    return True
...

    with connectable.connect() as connection:
        context.configure(
            connection=connection,
            target_metadata=target_metadata,
            version_table_schema=target_schema,
            include_schemas=True,
            include_name=include_name,
            include_object=include_object,
        )

I am working with alembic==1.18.1 and python 3.11

I would appreciate any help, thank you :)

[CaselIT]

Hi,

I believe this is a bug of the 1.18 series, that was fixed in version 1.18.3 by #1787

Can you try version 1.18.3?

[aholovenko]

Thanks a lot, the error doesn't raise now

[CaselIT]

ok, great, thanks for confirming!