From fc15c9a0c3c043c0a61dce625b8cd1ee121b4baf Mon Sep 17 00:00:00 2001
From: hung12ct <48434938+hung12ct@users.noreply.github.com>
Date: Wed, 29 Oct 2025 20:39:26 -0700
Subject: [PATCH] fix: Update DynamicPickleType to support MySQL dialect
Merge https://github.com/google/adk-python/pull/3282
The `process_bind_param` and `process_result_value` methods in the `DynamicPickleType` class have been modified to handle MySQL dialect in addition to Spanner. This change ensures that pickled values are correctly processed for both database types.
**Please ensure you have read the [contribution guide](https://github.com/google/adk-python/blob/main/CONTRIBUTING.md) before creating a pull request.**
### Link to Issue or Description of Change
**1. Link to an existing issue (if applicable):**
- Closes: #3283
**2. Or, if no issue exists, describe the change:**
_If applicable, please follow the issue templates to provide as much detail as
possible._
**Problem:**
When using `DatabaseSessionService` with MySQL backend in google-adk v1.17.0, the application crashes with the following error: app.resources.runner:event_generator:260 - Error in event_generator: (builtins.TypeError) 'tuple' object cannot be interpreted as an integer
Root cause: The `DynamicPickleType` class in `database_session_service.py` configures MySQL dialect to use `LONGBLOB` for storing pickled data (line 117-118), but the `process_bind_param` and `process_result_value` methods only handle pickle serialization/deserialization for Spanner dialect, not MySQL. This causes MySQL to attempt storing raw Python objects instead of pickled bytes, leading to serialization errors and potential data corruption.
**Solution:**
Added MySQL to the pickle serialization logic in both `process_bind_param` and `process_result_value` methods, treating it the same way as Spanner dialect. This ensures that:
- Data is properly pickled to bytes before being stored in MySQL's LONGBLOB column
- Data is properly unpickled when retrieved from the database
- No breaking changes to existing functionality for other dialects (SQLite, PostgreSQL)
### Testing Plan
_Please describe the tests that you ran to verify your changes. This is required
for all PRs that are not small documentation or typo fixes._
**Unit Tests:**
- [x] I have added or updated unit tests for my change.
- [x] All unit tests pass locally.
**Summary of `pytest` results:**
**Manual End-to-End (E2E) Tests:**
_Please provide instructions on how to manually test your changes, including any
necessary setup or configuration. Please provide logs or screenshots to help
reviewers better understand the fix._
### Checklist
- [x] I have read the [CONTRIBUTING.md](https://github.com/google/adk-python/blob/main/CONTRIBUTING.md) document.
- [x] I have performed a self-review of my own code.
- [x] I have commented my code, particularly in hard-to-understand areas.
- [x] I have added tests that prove my fix is effective or that my feature works.
- [x] New and existing unit tests pass locally with my changes.
- [x] I have manually tested my changes end-to-end.
- [x] Any dependent changes have been merged and published in downstream modules.
### Additional context
_Add any other context or screenshots about the feature request here._
COPYBARA_INTEGRATE_REVIEW=https://github.com/google/adk-python/pull/3282 from hung12ct:fix/mysql-pickle-serialization d9df37adb7dfbbfd8502a0fe65c4f8bca3d0d978
PiperOrigin-RevId: 825834360
---
.../adk/sessions/database_session_service.py | 4 +-
.../sessions/test_dynamic_pickle_type.py | 181 ++++++++++++++++++
2 files changed, 183 insertions(+), 2 deletions(-)
create mode 100644 tests/unittests/sessions/test_dynamic_pickle_type.py
diff --git a/src/google/adk/sessions/database_session_service.py b/src/google/adk/sessions/database_session_service.py
index 215a5d82..948fcbf8 100644
--- a/src/google/adk/sessions/database_session_service.py
+++ b/src/google/adk/sessions/database_session_service.py
@@ -125,14 +125,14 @@ class DynamicPickleType(TypeDecorator):
def process_bind_param(self, value, dialect):
"""Ensures the pickled value is a bytes object before passing it to the database dialect."""
if value is not None:
- if dialect.name == "spanner+spanner":
+ if dialect.name in ("spanner+spanner", "mysql"):
return pickle.dumps(value)
return value
def process_result_value(self, value, dialect):
"""Ensures the raw bytes from the database are unpickled back into a Python object."""
if value is not None:
- if dialect.name == "spanner+spanner":
+ if dialect.name in ("spanner+spanner", "mysql"):
return pickle.loads(value)
return value
diff --git a/tests/unittests/sessions/test_dynamic_pickle_type.py b/tests/unittests/sessions/test_dynamic_pickle_type.py
new file mode 100644
index 00000000..e4eb084f
--- /dev/null
+++ b/tests/unittests/sessions/test_dynamic_pickle_type.py
@@ -0,0 +1,181 @@
+# Copyright 2025 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import annotations
+
+import pickle
+from unittest import mock
+
+from google.adk.sessions.database_session_service import DynamicPickleType
+import pytest
+from sqlalchemy import create_engine
+from sqlalchemy.dialects import mysql
+
+
+@pytest.fixture
+def pickle_type():
+ """Fixture for DynamicPickleType instance."""
+ return DynamicPickleType()
+
+
+def test_load_dialect_impl_mysql(pickle_type):
+ """Test that MySQL dialect uses LONGBLOB."""
+ # Mock the MySQL dialect
+ mock_dialect = mock.Mock()
+ mock_dialect.name = "mysql"
+
+ # Mock the return value of type_descriptor
+ mock_longblob_type = mock.Mock()
+ mock_dialect.type_descriptor.return_value = mock_longblob_type
+
+ impl = pickle_type.load_dialect_impl(mock_dialect)
+
+ # Verify type_descriptor was called once with mysql.LONGBLOB
+ mock_dialect.type_descriptor.assert_called_once_with(mysql.LONGBLOB)
+ # Verify the return value is what we expect
+ assert impl == mock_longblob_type
+
+
+def test_load_dialect_impl_spanner(pickle_type):
+ """Test that Spanner dialect uses SpannerPickleType."""
+ # Mock the spanner dialect
+ mock_dialect = mock.Mock()
+ mock_dialect.name = "spanner+spanner"
+
+ with mock.patch(
+ "google.cloud.sqlalchemy_spanner.sqlalchemy_spanner.SpannerPickleType"
+ ) as mock_spanner_type:
+ pickle_type.load_dialect_impl(mock_dialect)
+ mock_dialect.type_descriptor.assert_called_once_with(mock_spanner_type)
+
+
+def test_load_dialect_impl_default(pickle_type):
+ """Test that other dialects use default PickleType."""
+ engine = create_engine("sqlite:///:memory:")
+ dialect = engine.dialect
+ impl = pickle_type.load_dialect_impl(dialect)
+ # Should return the default impl (PickleType)
+ assert impl == pickle_type.impl
+
+
+@pytest.mark.parametrize(
+ "dialect_name",
+ [
+ pytest.param("mysql", id="mysql"),
+ pytest.param("spanner+spanner", id="spanner"),
+ ],
+)
+def test_process_bind_param_pickle_dialects(pickle_type, dialect_name):
+ """Test that MySQL and Spanner dialects pickle the value."""
+ mock_dialect = mock.Mock()
+ mock_dialect.name = dialect_name
+
+ test_data = {"key": "value", "nested": [1, 2, 3]}
+ result = pickle_type.process_bind_param(test_data, mock_dialect)
+
+ # Should be pickled bytes
+ assert isinstance(result, bytes)
+ # Should be able to unpickle back to original
+ assert pickle.loads(result) == test_data
+
+
+def test_process_bind_param_default(pickle_type):
+ """Test that other dialects return value as-is."""
+ mock_dialect = mock.Mock()
+ mock_dialect.name = "sqlite"
+
+ test_data = {"key": "value"}
+ result = pickle_type.process_bind_param(test_data, mock_dialect)
+
+ # Should return value unchanged (SQLAlchemy's PickleType handles it)
+ assert result == test_data
+
+
+def test_process_bind_param_none(pickle_type):
+ """Test that None values are handled correctly."""
+ mock_dialect = mock.Mock()
+ mock_dialect.name = "mysql"
+
+ result = pickle_type.process_bind_param(None, mock_dialect)
+ assert result is None
+
+
+@pytest.mark.parametrize(
+ "dialect_name",
+ [
+ pytest.param("mysql", id="mysql"),
+ pytest.param("spanner+spanner", id="spanner"),
+ ],
+)
+def test_process_result_value_pickle_dialects(pickle_type, dialect_name):
+ """Test that MySQL and Spanner dialects unpickle the value."""
+ mock_dialect = mock.Mock()
+ mock_dialect.name = dialect_name
+
+ test_data = {"key": "value", "nested": [1, 2, 3]}
+ pickled_data = pickle.dumps(test_data)
+
+ result = pickle_type.process_result_value(pickled_data, mock_dialect)
+
+ # Should be unpickled back to original
+ assert result == test_data
+
+
+def test_process_result_value_default(pickle_type):
+ """Test that other dialects return value as-is."""
+ mock_dialect = mock.Mock()
+ mock_dialect.name = "sqlite"
+
+ test_data = {"key": "value"}
+ result = pickle_type.process_result_value(test_data, mock_dialect)
+
+ # Should return value unchanged (SQLAlchemy's PickleType handles it)
+ assert result == test_data
+
+
+def test_process_result_value_none(pickle_type):
+ """Test that None values are handled correctly."""
+ mock_dialect = mock.Mock()
+ mock_dialect.name = "mysql"
+
+ result = pickle_type.process_result_value(None, mock_dialect)
+ assert result is None
+
+
+@pytest.mark.parametrize(
+ "dialect_name",
+ [
+ pytest.param("mysql", id="mysql"),
+ pytest.param("spanner+spanner", id="spanner"),
+ ],
+)
+def test_roundtrip_pickle_dialects(pickle_type, dialect_name):
+ """Test full roundtrip for MySQL and Spanner: bind -> result."""
+ mock_dialect = mock.Mock()
+ mock_dialect.name = dialect_name
+
+ original_data = {
+ "string": "test",
+ "number": 42,
+ "list": [1, 2, 3],
+ "nested": {"a": 1, "b": 2},
+ }
+
+ # Simulate bind (Python -> DB)
+ bound_value = pickle_type.process_bind_param(original_data, mock_dialect)
+ assert isinstance(bound_value, bytes)
+
+ # Simulate result (DB -> Python)
+ result_value = pickle_type.process_result_value(bound_value, mock_dialect)
+ assert result_value == original_data