fix: add create_engine() method to SQLAlchemy configs.

This PR fixes a break in backward compatibility where the `create_engine()`
method was removed from the SQLAlchemy config types in a minor version
increment.

litestar/contrib/sqlalchemy/plugins/init/config/asyncio.py

@@ -2,10 +2,15 @@
 
 from advanced_alchemy.config.asyncio import AlembicAsyncConfig, AsyncSessionConfig
 from advanced_alchemy.extensions.litestar.plugins.init.config.asyncio import (
-    SQLAlchemyAsyncConfig,
+    SQLAlchemyAsyncConfig as _SQLAlchemyAsyncConfig,
+)
+from advanced_alchemy.extensions.litestar.plugins.init.config.asyncio import (
     autocommit_before_send_handler,
     default_before_send_handler,
 )
+from sqlalchemy.ext.asyncio import AsyncEngine
+
+from litestar.contrib.sqlalchemy.plugins.init.config.compat import _CreateEngineMixin
 
 __all__ = (
     "SQLAlchemyAsyncConfig",
@@ -14,3 +19,7 @@
     "default_before_send_handler",
     "autocommit_before_send_handler",
 )
+
+
+class SQLAlchemyAsyncConfig(_SQLAlchemyAsyncConfig, _CreateEngineMixin[AsyncEngine]):
+    ...

litestar/contrib/sqlalchemy/plugins/init/config/compat.py

@@ -0,0 +1,23 @@
+from __future__ import annotations
+
+from typing import TYPE_CHECKING, Generic, Protocol, TypeVar
+
+from litestar.utils.deprecation import deprecated
+
+if TYPE_CHECKING:
+    from sqlalchemy import Engine
+    from sqlalchemy.ext.asyncio import AsyncEngine
+
+
+EngineT_co = TypeVar("EngineT_co", bound="Engine | AsyncEngine", covariant=True)
+
+
+class HasGetEngine(Protocol[EngineT_co]):
+    def get_engine(self) -> EngineT_co:
+        ...
+
+
+class _CreateEngineMixin(Generic[EngineT_co]):
+    @deprecated(version="2.1.1", removal_in="3.0.0", alternative="get_engine()")
+    def create_engine(self: HasGetEngine[EngineT_co]) -> EngineT_co:
+        return self.get_engine()

litestar/contrib/sqlalchemy/plugins/init/config/sync.py

@@ -2,10 +2,15 @@
 
 from advanced_alchemy.config.sync import AlembicSyncConfig, SyncSessionConfig
 from advanced_alchemy.extensions.litestar.plugins.init.config.sync import (
-    SQLAlchemySyncConfig,
+    SQLAlchemySyncConfig as _SQLAlchemySyncConfig,
+)
+from advanced_alchemy.extensions.litestar.plugins.init.config.sync import (
     autocommit_before_send_handler,
     default_before_send_handler,
 )
+from sqlalchemy import Engine
+
+from litestar.contrib.sqlalchemy.plugins.init.config.compat import _CreateEngineMixin
 
 __all__ = (
     "SQLAlchemySyncConfig",
@@ -14,3 +19,7 @@
     "default_before_send_handler",
     "autocommit_before_send_handler",
 )
+
+
+class SQLAlchemySyncConfig(_SQLAlchemySyncConfig, _CreateEngineMixin[Engine]):
+    ...

tests/unit/test_contrib/test_sqlalchemy/test_init_plugin/test_config/test_asyncio.py

@@ -0,0 +1,20 @@
+from __future__ import annotations
+
+import pytest
+from sqlalchemy.ext.asyncio import AsyncEngine, create_async_engine
+
+from litestar.contrib.sqlalchemy.plugins.init.config.asyncio import SQLAlchemyAsyncConfig
+
+
+def test_create_engine_with_engine_instance() -> None:
+    engine = create_async_engine("sqlite+aiosqlite:///:memory:")
+    config = SQLAlchemyAsyncConfig(engine_instance=engine)
+    with pytest.deprecated_call():
+        assert engine is config.create_engine()
+
+
+def test_create_engine_with_connection_string() -> None:
+    config = SQLAlchemyAsyncConfig(connection_string="sqlite+aiosqlite:///:memory:")
+    with pytest.deprecated_call():
+        engine = config.create_engine()
+    assert isinstance(engine, AsyncEngine)

tests/unit/test_contrib/test_sqlalchemy/test_init_plugin/test_config/test_sync.py

@@ -0,0 +1,20 @@
+from __future__ import annotations
+
+import pytest
+from sqlalchemy import Engine, create_engine
+
+from litestar.contrib.sqlalchemy.plugins.init.config.sync import SQLAlchemySyncConfig
+
+
+def test_create_engine_with_engine_instance() -> None:
+    engine = create_engine("sqlite:///:memory:")
+    config = SQLAlchemySyncConfig(engine_instance=engine)
+    with pytest.deprecated_call():
+        assert engine is config.create_engine()
+
+
+def test_create_engine_with_connection_string() -> None:
+    config = SQLAlchemySyncConfig(connection_string="sqlite:///:memory:")
+    with pytest.deprecated_call():
+        engine = config.create_engine()
+    assert isinstance(engine, Engine)