support sqlite date casts in batch mode under sqlite.cast_for_batch_migrate, or at least a hook

I am trying to migrate a column from type Date to type Datetime. Here the migration script:

from alembic import op
import sqlalchemy as sa

def upgrade():
with op.batch_alter_table('col_1', schema=None) as batch_op:
batch_op.alter_column('date',
existing_type=sa.DATE,
type_=sa.DateTime,
existing_nullable=False)

I would expect the new column to contain text of the ISO8601 format ( I am operating on an SQLite database).

Running the upgrade command the migration does not throw any exception. Here the stdout:
INFO [alembic.runtime.migration] Context impl SQLiteImpl.
INFO [alembic.runtime.migration] Will assume non-transactional DDL.
INFO [alembic.runtime.migration] Running upgrade -> 0a2d90c1423d, empty message

The modified column after contains only the year instead, i.e. 4 characters.

I am running:

• OS: Ubuntu 20.04.4 LTS
• Python: 3.9.12
• Alembic: 1.7.7
• SQLAlchemy: 1.4.36

Start by reproducing the Date-to-DateTime migration with SQLite and inspect the batch_alter_table path around sqlite.cast_for_batch_migrate. Determine whether the conversion can preserve ISO8601 date text or needs an exposed hook, then add coverage for the migration behavior and document what is supported.