"""Reconcile the database with what the models have always claimed (#3275).

Milestone 328 discovered ~130 places where the ORM models and the deployed
schema disagreed. Almost all of them were the MODEL being wrong — missing
`server_default`s, indexes and CHECK constraints that only ever existed in a
migration — and those are fixed in the model files with no DDL at all, because
the database already had them.

This migration carries the remainder: the one case where the MODEL was right
and the database was missing something.

`tag.fandom_id` is declared `index=True` on the model, but no migration ever
created that index. Every autogenerate run since would have proposed adding
it; nobody ran one, so the model and the database simply drifted apart and
stayed that way.

Deliberately NOT in this migration: making `image_record.sha256` unique. The
model says `unique=True` and `0001` created a plain, non-unique index, so
duplicates are possible today and the ORM believes they are not. Adding the
constraint is a real change that FAILS if duplicates already exist, and if
they do exist the right response is a dedupe decision rather than a constraint
— so it needs an answer about live data before it is written, not after.
Tracked in #3275.

Revision ID: 0088
Revises: 0087
Create Date: 2026-08-30

"""
from typing import Sequence, Union

from alembic import op

revision: str = "0088"
down_revision: Union[str, None] = "0087"
branch_labels: Union[str, Sequence[str], None] = None
depends_on: Union[str, Sequence[str], None] = None


def upgrade() -> None:
    # IF NOT EXISTS because the index is what the model already asks for: any
    # database built from metadata rather than from this chain will have it,
    # and this migration must be a no-op there rather than an error.
    op.execute("CREATE INDEX IF NOT EXISTS ix_tag_fandom_id ON tag (fandom_id)")


def downgrade() -> None:
    op.execute("DROP INDEX IF EXISTS ix_tag_fandom_id")