"""fix accounts.owner_id to be nullable (circular FK with users)

Revision ID: 021
Revises: 020
Create Date: 2026-02-07

The original migration 020 enforced NOT NULL on owner_id, but this creates
a circular FK problem: Account needs owner_id (User) and User needs
account_id (Account). Making owner_id nullable resolves this — we create
the Account first, then the User, then set owner_id.
"""
from typing import Sequence, Union

from alembic import op
import sqlalchemy as sa


# revision identifiers, used by Alembic.
revision: str = '021'
down_revision: Union[str, None] = '020'
branch_labels: Union[str, Sequence[str], None] = None
depends_on: Union[str, Sequence[str], None] = None


def upgrade() -> None:
    op.alter_column('accounts', 'owner_id', nullable=True)


def downgrade() -> None:
    op.alter_column('accounts', 'owner_id', nullable=False)