Alembic detects existing changes if db username equals postgres schema name

[Alexey Vasilenko]

Describe the bug

Alembic detects existing changes if db username equals postgres schema name.
Problem occurs only if parameter include_name is passed in env.py.

Expected behavior
Alembic generates empty migration.

To Reproduce

Project structure

.
├── alembic.ini
└── src
    ├── migrations
    │   ├── env.py
    │   ├── script.py.mako
    │   └── versions
    │       └── 20240318_2128_722179d9516c_initial.py
    └── models.py

File: src/models.py

from sqlalchemy import MetaData, Column, BigInteger, String, Identity
from sqlalchemy.orm import DeclarativeBase

metadata = MetaData(schema='example')


class Base(DeclarativeBase):
    metadata = metadata


class Customer(Base):
    __tablename__ = 'customers'

    id = Column(BigInteger, Identity(always=True), primary_key=True)
    name = Column(String)
    email = Column(String)

File: src/migrations/env.py

from logging.config import fileConfig

from sqlalchemy import engine_from_config
from sqlalchemy import pool

from alembic import context

from models import Base

config = context.config


if config.config_file_name is not None:
    fileConfig(config.config_file_name)

target_metadata = Base.metadata


def include_name(name, type_, parent_names):
    if type_ == 'schema':
        return name == target_metadata.schema

    return True


def run_migrations_offline() -> None:
    url = config.get_main_option("sqlalchemy.url")
    context.configure(
        url=url,
        target_metadata=target_metadata,
        literal_binds=True,
        include_name=include_name,
        include_schemas=True,
        dialect_opts={"paramstyle": "named"},
    )

    with context.begin_transaction():
        context.run_migrations()


def run_migrations_online() -> None:
    connectable = engine_from_config(
        config.get_section(config.config_ini_section, {}),
        prefix="sqlalchemy.",
        poolclass=pool.NullPool,
    )

    with connectable.connect() as connection:
        context.configure(
            connection=connection,
            target_metadata=target_metadata,
            include_name=include_name,
            include_schemas=True,
        )

        with context.begin_transaction():
            context.run_migrations()


if context.is_offline_mode():
    run_migrations_offline()
else:
    run_migrations_online()

File: src/migrations/versions/20240318_2128_722179d9516c_initial.py

"""initial

Revision ID: 722179d9516c
Revises: 
Create Date: 2024-03-18 21:28:38.818940

"""
from typing import Sequence, Union

from alembic import op
import sqlalchemy as sa


# revision identifiers, used by Alembic.
revision: str = '722179d9516c'
down_revision: Union[str, None] = None
branch_labels: Union[str, Sequence[str], None] = None
depends_on: Union[str, Sequence[str], None] = None


def upgrade() -> None:
    op.execute('CREATE SCHEMA example')
    # ### commands auto generated by Alembic - please adjust! ###
    op.create_table('customers',
    sa.Column('id', sa.BigInteger(), sa.Identity(always=True), nullable=False),
    sa.Column('name', sa.String(), nullable=True),
    sa.Column('email', sa.String(), nullable=True),
    sa.PrimaryKeyConstraint('id'),
    schema='example'
    )
    # ### end Alembic commands ###


def downgrade() -> None:
    # ### commands auto generated by Alembic - please adjust! ###
    op.drop_table('customers', schema='example')
    # ### end Alembic commands ###
    op.execute('DROP SCHEMA example')

alembic.ini

[alembic]
script_location = src/migrations

file_template = %%(year)d%%(month).2d%%(day).2d_%%(hour).2d%%(minute).2d_%%(rev)s_%%(slug)s

prepend_sys_path = .

version_path_separator = os

sqlalchemy.url = postgresql://example:pass@localhost:5432/db

# Logging configuration
[loggers]
keys = root,sqlalchemy,alembic

[handlers]
keys = console

[formatters]
keys = generic

[logger_root]
level = WARN
handlers = console
qualname =

[logger_sqlalchemy]
level = WARN
handlers =
qualname = sqlalchemy.engine

[logger_alembic]
level = INFO
handlers =
qualname = alembic

[handler_console]
class = StreamHandler
args = (sys.stderr,)
level = NOTSET
formatter = generic

[formatter_generic]
format = %(levelname)-5.5s [%(name)s] %(message)s
datefmt = %H:%M:%S

sqlalchemy.url in alembic.ini: postgresql://example:pass@localhost:5432/db

alembic upgrade head
alembic revision --autogenerate -m "test"

Output:

INFO  [alembic.autogenerate.compare] Detected added table 'customers'

Autogenerated migration:

def upgrade() -> None:
    # ### commands auto generated by Alembic - please adjust! ###
    op.create_table('customers',
    sa.Column('id', sa.BigInteger(), sa.Identity(always=True), nullable=False),
    sa.Column('name', sa.String(), nullable=True),
    sa.Column('email', sa.String(), nullable=True),
    sa.PrimaryKeyConstraint('id'),
    schema='example'
    )
    # ### end Alembic commands ###


def downgrade() -> None:
    # ### commands auto generated by Alembic - please adjust! ###
    op.drop_table('customers', schema='example')
    # ### end Alembic commands ###

If I change the username in DSN (postgresql://user:pass@localhost:5432/db) to something that is not equal to the schema name, I get an empty migration.

def upgrade() -> None:
    # ### commands auto generated by Alembic - please adjust! ###
    pass
    # ### end Alembic commands ###


def downgrade() -> None:
    # ### commands auto generated by Alembic - please adjust! ###
    pass
    # ### end Alembic commands ###

Error
No errors.

Versions.

• OS: Ubuntu 22.04.4 LTS
• Python: Python 3.11.6
• Alembic: alembic 1.13.1
• SQLAlchemy: 2.0.28
• Database: PostgreSQL
• DBAPI: psycopg2-binary==2.9.9

Have a nice day!