Here's how I solved it that gives a little more control:

alembic/enum_migration.py

import logging
from typing import Optional

from alembic.autogenerate.api import AutogenContext
from alembic.autogenerate.compare import comparators
from alembic.operations.ops import AlterColumnOp
from sqlalchemy import Enum as SQLAEnum
from sqlalchemy.dialects.mysql import ENUM as MySQLEnum
from sqlalchemy.sql.schema import Column

logger: logging.Logger = logging.getLogger(__name__)


@comparators.dispatch_for("column")
def compare_column(
    autogen_context: AutogenContext,
    modify_ops: AlterColumnOp,
    schema: Optional[str],
    table_name: str,
    column_name: str,
    db_column: Column[MySQLEnum],
    model_column: Column[SQLAEnum],
) -> None:
    """Compare a column's model definition with its database state and modify the AlterColumnOp accordingly."""

    if isinstance(model_column.type, SQLAEnum) and isinstance(db_column.type, MySQLEnum):
        model_values: set[str] = set(model_column.type.enums)
        db_values: set[str] = set(db_column.type.enums)

        logger.debug(f"Comparing {table_name}.{column_name} db_values={db_values}, model_values={model_values}")

        if model_values ^ db_values:
            if new_values := model_values - db_values:
                logger.info(f"New values detected for Enum {table_name}.{column_name}: {', '.join(new_values)}")

            if removed_values := db_values - model_values:
                logger.info(f"Removed values detected for Enum {table_name}.{column_name}: {', '.join(removed_values)}")

            modify_ops.modify_type = model_column.type
            modify_ops.existing_type = SQLAEnum(*db_values, name=db_column.type.name or model_column.type.name)
            modify_ops.existing_nullable = db_column.nullable

and then in the alembic/env.py:

import enum_migration  # NOQA

Uh oh!

Uh oh!

implement type detection change for MySQL ENUM #779

Description

Metadata

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Issue actions