Include "info" dict in create_table statement

[BayerSe]

Hi,

our Oracle db requires partitions for some of the tables, which we used to add using alembic with the following steps. These are based on the proposal of @zzzeek here (for nicer formatting see here).

It's been a long time since I needed a change in the schema, so I only now realized that there seems to have been a regression / change in behavior.

Main code:

from sqlalchemy import MetaData, Column, String
from sqlalchemy.ext.declarative import declarative_base

metadata = MetaData()
Base = declarative_base(metadata=metadata)


class Table(Base):
    __tablename__ = 'Table'
    name = Column(String(10), primary_key=True)
    __table_args__ = {'info': {'oracle_partition': "PARTITION BY ..."}}

This rewriter is added as process_revision_directives of context.configure in env.py with the goal of adding the info dict to the create_table statement:

writer = rewriter.Rewriter()

@writer.rewrites(ops.CreateTableOp)
def add_info_to_table(context, revision, op):
    op.kw["info"] = op.columns[0].table.info
    return ops.CreateTableOp(
            table_name=op.table_name,
            columns=op.columns,
            schema=op.schema,
            _namespace_metadata=op._namespace_metadata,
            _constraints_included=op._constraints_included,
            **op.kw,
        )

We add this to the migration scripts, which adds the partition command to the created statement:

import sqlalchemy as sa
from alembic import op
import textwrap

@sa.ext.compiler.compiles(sa.schema.CreateTable, "oracle")
def _add_suffixes(element, compiler, **kw):  # type: ignore
    text = compiler.visit_create_table(element, **kw)
    if "oracle_partition" in element.element.info:
        text += textwrap.dedent(element.element.info["oracle_partition"]).strip()
    return text

For alembic==1.6.5 and sqlalchemy==1.3.24 this result in the following auto-generated update command:

op.create_table(
    "Table",
    sa.Column("name", sa.String(length=10), nullable=False),
    sa.PrimaryKeyConstraint("name"),
    info={"oracle_partition": "PARTITION BY ..."},
)

However, for alembic==1.12.0 and sqlalchemy==2.0.22, the info is not added anymore, i.e. I just get

op.create_table(
    "Table",
    sa.Column("name", sa.String(length=10), nullable=False),
    sa.PrimaryKeyConstraint("name"),
)

I checked version alembic==1.7.0 as well, it broke between 1.6.5 and 1.7.0. In the changelog I found this comment, could that be related?

Thanks and regards
Sebastian

[zzzeek]

well at the very least there's a typing error with Rewriter being sent to process_revision_directives

[zzzeek]

IIUC the bug here is an autogenerate rendering issue. rendering "info" overall though doesnt seem like something we would have been doing in any case, it can have anything inside of it that we would not know how to render.

are you sure this used to render "info" at some point?

[zzzeek]

hmm looks like the code shoudl be doing it though. strange

[BayerSe]

Thanks for the quick response! Yes I'm sure it works for version 1.6.5, but not for 1.7.0.

[zzzeek]

oh yes I guess 1ce8166 would have reversed this then since it's popping it.

issue is in #1329

[BayerSe]

Thanks!