fix: InvalidRequestError when calling create_session_maker (#701)

## Summary

- Fixes `sqlalchemy.exc.InvalidRequestError: No such event 'before_flush' for target 'async_sessionmaker(...)'` raised when calling `SQLAlchemyAsyncConfig.create_session_maker()`

## Root Cause

SQLAlchemy's `async_sessionmaker` does not support session-level events (`before_flush`, `after_commit`, `after_rollback`) only the sync `sessionmaker` does. The code was registering these events directly on the `async_sessionmaker` instance, which SQLAlchemy rejects.

## Fix

Instead of attaching events to the `async_sessionmaker`

1. Creates a sync `sessionmaker()`
2. Registers all session-level events (`before_flush`, `after_commit`, `after_rollback`) on it
3. Injects it into the `async_sessionmaker` via `session_maker.configure(sync_session_class=sync_maker)`

This ensures every `AsyncSession` created by the factory uses this sync sessionmaker internally, and all event listeners fire correctly on the underlying sync `Session`.

Author: Harshal6927

.pre-commit-config.yaml

@@ -22,7 +22,7 @@ repos:
       - id: unasyncd
         additional_dependencies: ["ruff"]
   - repo: https://github.com/charliermarsh/ruff-pre-commit
-    rev: "v0.15.7"
+    rev: "v0.15.9"
     hooks:
       # Run the linter.
       - id: ruff

advanced_alchemy/config/asyncio.py

@@ -4,6 +4,7 @@
 from typing import TYPE_CHECKING, Callable, Optional, Union, cast
 
 from sqlalchemy.ext.asyncio import AsyncConnection, AsyncEngine, AsyncSession, async_sessionmaker, create_async_engine
+from sqlalchemy.orm import sessionmaker as sync_sessionmaker
 
 from advanced_alchemy._listeners import set_async_context
 from advanced_alchemy.config.common import (
@@ -162,14 +163,20 @@ def create_session_maker(self) -> "Callable[[], AsyncSession]":
                 "async_sessionmaker[AsyncSession]",
                 self.session_maker,  # pyright: ignore[reportUnknownMemberType]
             )
+
+            # async_sessionmaker does not support Session-level events directly.
+            # Create a sync sessionmaker, register events on it, and inject it
+            # as sync_session_class so events fire on the underlying sync Session.
+            sync_maker = sync_sessionmaker()
             if self.enable_file_object_listener:
-                event.listen(session_maker, "before_flush", AsyncFileObjectListener.before_flush)
-                event.listen(session_maker, "after_commit", AsyncFileObjectListener.after_commit)
-                event.listen(session_maker, "after_rollback", AsyncFileObjectListener.after_rollback)
+                event.listen(sync_maker, "before_flush", AsyncFileObjectListener.before_flush)
+                event.listen(sync_maker, "after_commit", AsyncFileObjectListener.after_commit)
+                event.listen(sync_maker, "after_rollback", AsyncFileObjectListener.after_rollback)
             if self.enable_touch_updated_timestamp_listener:
-                event.listen(session_maker, "before_flush", touch_updated_timestamp)
-            event.listen(session_maker, "after_commit", AsyncCacheListener.after_commit)
-            event.listen(session_maker, "after_rollback", AsyncCacheListener.after_rollback)
+                event.listen(sync_maker, "before_flush", touch_updated_timestamp)
+            event.listen(sync_maker, "after_commit", AsyncCacheListener.after_commit)
+            event.listen(sync_maker, "after_rollback", AsyncCacheListener.after_rollback)
+            session_maker.configure(sync_session_class=sync_maker)
 
         if self.session_maker is None:  # pyright: ignore
             msg = "Session maker was not initialized."  # type: ignore[unreachable]

advanced_alchemy/repository/_async.py

@@ -678,7 +678,7 @@ def _get_error_messages(
         if default_messages and isinstance(default_messages, dict):
             messages.update(default_messages)
         if error_messages:
-            messages.update(cast("ErrorMessages", error_messages))
+            messages.update(cast("ErrorMessages", error_messages))  # type: ignore[unused-ignore,redundant-cast]
         return messages
 
     @classmethod

advanced_alchemy/repository/_sync.py

@@ -679,7 +679,7 @@ def _get_error_messages(
         if default_messages and isinstance(default_messages, dict):
             messages.update(default_messages)
         if error_messages:
-            messages.update(cast("ErrorMessages", error_messages))
+            messages.update(cast("ErrorMessages", error_messages))  # type: ignore[unused-ignore,redundant-cast]
         return messages
 
     @classmethod

advanced_alchemy/repository/memory/_async.py

@@ -228,9 +228,9 @@ def _get_error_messages(
             default_messages = None
         messages = cast("ErrorMessages", dict(DEFAULT_ERROR_MESSAGE_TEMPLATES))
         if default_messages:
-            messages.update(cast("ErrorMessages", default_messages))
+            messages.update(cast("ErrorMessages", default_messages))  # type: ignore[unused-ignore,redundant-cast]
         if error_messages:
-            messages.update(cast("ErrorMessages", error_messages))
+            messages.update(cast("ErrorMessages", error_messages))  # type: ignore[unused-ignore,redundant-cast]
         return messages
 
     @classmethod

advanced_alchemy/repository/memory/_sync.py

@@ -229,9 +229,9 @@ def _get_error_messages(
             default_messages = None
         messages = cast("ErrorMessages", dict(DEFAULT_ERROR_MESSAGE_TEMPLATES))
         if default_messages:
-            messages.update(cast("ErrorMessages", default_messages))
+            messages.update(cast("ErrorMessages", default_messages))  # type: ignore[unused-ignore,redundant-cast]
         if error_messages:
-            messages.update(cast("ErrorMessages", error_messages))
+            messages.update(cast("ErrorMessages", error_messages))  # type: ignore[unused-ignore,redundant-cast]
         return messages
 
     @classmethod

advanced_alchemy/service/_util.py

@@ -215,7 +215,7 @@ def to_schema(
             )
         if MSGSPEC_INSTALLED and issubclass(schema_type, Struct):
             if not isinstance(data, Sequence):
-                return cast(  # type: ignore[redundant-cast]
+                return cast(
                     "ModelDTOT",
                     convert(
                         obj=data,

pyproject.toml

@@ -462,23 +462,14 @@ warn_unused_ignores = false
 ignore_missing_imports = true
 module = [
   "asyncmy",
-  "pyodbc",
   "greenlet",
   "google.auth.*",
   "google.cloud.*",
-  "google.protobuf.*",
   "pyarrow.*",
-  "pytest_docker.*",
-  "googleapiclient",
-  "googleapiclient.*",
   "uuid_utils",
-  "uuid_utils.*",
   "fsspec",
   "fsspec.*",
-  "gcsfs",
-  "fastnanoid",
   "s3fs",
-  "s3fs.*",
   "argon2",
   "argon2.*",
 ]
@@ -491,12 +482,12 @@ module = ["dishka", "dishka.*"]
 [[tool.mypy.overrides]]
 follow_imports = "skip"
 ignore_missing_imports = true
-module = ["pytest", "pytest.*", "_pytest", "_pytest.*"]
+module = ["pytest", "_pytest.*"]
 
 [[tool.mypy.overrides]]
 follow_imports = "skip"
 ignore_missing_imports = true
-module = ["sphinx", "sphinx.*"]
+module = ["sphinx.*"]
 
 [[tool.mypy.overrides]]
 module = "advanced_alchemy._serialization"

tests/unit/test_config/test_async_config.py

@@ -33,7 +33,10 @@ def test_create_session_maker_standard_path() -> None:
             return_value=mock_session_maker,
         ),
         patch("sqlalchemy.event.listen") as mock_listen,
+        patch("advanced_alchemy.config.asyncio.sync_sessionmaker") as mock_sync_maker_factory,
     ):
+        mock_sync_maker = MagicMock()
+        mock_sync_maker_factory.return_value = mock_sync_maker
         result = config.create_session_maker()
 
     assert result is mock_session_maker
@@ -42,6 +45,14 @@ def test_create_session_maker_standard_path() -> None:
     #                  after_commit, after_rollback for cache
     assert mock_listen.call_count == 6
 
+    # Verify session_maker.configure was called with the sync_maker
+    mock_session_maker.configure.assert_called_once_with(sync_session_class=mock_sync_maker)
+
+    # Verify listeners are attached to the sync_maker, not the async session_maker
+    for call in mock_listen.call_args_list:
+        assert call.args[0] is mock_sync_maker
+        assert call.args[0] is not mock_session_maker
+
     # Verify file object listeners
     listener_events = [c.args[1] for c in mock_listen.call_args_list]
     assert "before_flush" in listener_events

tests/unit/test_extensions/test_fastapi/test_providers.py

@@ -60,7 +60,7 @@ def test_add_get_dependencies_cache() -> None:
         assert cache.get_dependencies(key) == deps1  # type: ignore
 
         # Test retrieving non-existent key
-        assert cache.get_dependencies(hash("nonexistent")) is None
+        assert cache.get_dependencies(hash("nonexistent")) is None  # type: ignore[unreachable]
 
 
 def test_create_filter_dependencies_cache_hit() -> None:
@@ -84,7 +84,7 @@ def test_create_filter_dependencies_cache_hit() -> None:
                 assert deps == mock_deps  # type: ignore
 
                 # Verify aggregate function builder was NOT called
-                mock_create.assert_not_called()
+                mock_create.assert_not_called()  # type: ignore[unreachable]
 
                 # Verify cache wasn't updated again
                 mock_add.assert_not_called()