Add DB-API sqlcomment mysql_client_version fallback

CHANGELOG.md

@@ -96,6 +96,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   ([#4081](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/4081))
 - `opentelemetry-instrumentation-system-metrics`: Use proper numeric `cpython.gc.generation` attribute in CPython metrics, out of spec `generation` attribute is deprecated and will be removed in the future
   ([#4092](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/4092))
+- `opentelemetry-instrumentation-dbapi`: Fix sqlcomment calculation of mysql_client_version field if connection reassignment, with "unknown" fallback
+  ([#3729](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/3729))
 - `opentelemetry-instrumentation-confluent-kafka`: Fix incorrect number of argument to `_inner_wrap_close`
   ([#3922](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/3922))
 

instrumentation/opentelemetry-instrumentation-dbapi/src/opentelemetry/instrumentation/dbapi/__init__.py

@@ -632,8 +632,22 @@ def _capture_mysql_version(self, cursor) -> None:
                 "mysql_client_version"
             ]
         ):
+            try:
+                # Autoinstrumentation and some programmatic calls
+                client_version = cursor._cnx._cmysql.get_client_info()
+            except AttributeError:
+                # Other programmatic instrumentation with reassigned wrapped connection
+                try:
+                    client_version = (
+                        cursor._connection._cmysql.get_client_info()
+                    )
+                except AttributeError as exc:
+                    _logger.debug(
+                        "Could not set mysql_client_version: %s", exc
+                    )
+                    client_version = "unknown"
             self._db_api_integration.commenter_data["mysql_client_version"] = (
-                cursor._cnx._cmysql.get_client_info()
+                client_version
             )
 
     def _get_commenter_data(self) -> dict:

instrumentation/opentelemetry-instrumentation-dbapi/tests/test_dbapi_integration.py

@@ -1180,6 +1180,89 @@ def test_non_string_sql_conversion(self):
         spans_list = self.memory_exporter.get_finished_spans()
         self.assertEqual(len(spans_list), 1)
 
+    def test_capture_mysql_version_primary_success(self):
+        connect_module = mock.MagicMock()
+        connect_module.__name__ = "mysql.connector"
+        connect_module.__version__ = "2.2.9"
+        db_integration = dbapi.DatabaseApiIntegration(
+            "instrumenting_module_test_name",
+            "mysql",
+            enable_commenter=True,
+            connect_module=connect_module,
+        )
+        mock_cursor = mock.MagicMock()
+        mock_cursor._cnx._cmysql.get_client_info.return_value = "8.0.32"
+        mock_connection = db_integration.wrapped_connection(
+            mock_connect, {}, {}
+        )
+        cursor = mock_connection.cursor()
+        cursor._cnx = mock_cursor._cnx
+        cursor.execute("SELECT 1;")
+        mock_cursor._cnx._cmysql.get_client_info.assert_called_once()
+        self.assertEqual(
+            db_integration.commenter_data["mysql_client_version"], "8.0.32"
+        )
+
+    def test_capture_mysql_version_fallback_success(self):
+        connect_module = mock.MagicMock()
+        connect_module.__name__ = "mysql.connector"
+        connect_module.__version__ = "2.2.9"
+        db_integration = dbapi.DatabaseApiIntegration(
+            "instrumenting_module_test_name",
+            "mysql",
+            enable_commenter=True,
+            connect_module=connect_module,
+        )
+        mock_cursor = mock.MagicMock()
+        mock_cursor._cnx._cmysql.get_client_info.side_effect = AttributeError(
+            "Primary method failed"
+        )
+        mock_cursor._connection._cmysql.get_client_info.return_value = "8.0.33"
+        mock_connection = db_integration.wrapped_connection(
+            mock_connect, {}, {}
+        )
+        cursor = mock_connection.cursor()
+        cursor._cnx = mock_cursor._cnx
+        cursor._connection = mock_cursor._connection
+        cursor.execute("SELECT 1;")
+        mock_cursor._cnx._cmysql.get_client_info.assert_called_once()
+        mock_cursor._connection._cmysql.get_client_info.assert_called_once()
+        self.assertEqual(
+            db_integration.commenter_data["mysql_client_version"], "8.0.33"
+        )
+
+    @mock.patch("opentelemetry.instrumentation.dbapi._logger")
+    def test_capture_mysql_version_fallback(self, mock_logger):
+        connect_module = mock.MagicMock()
+        connect_module.__name__ = "mysql.connector"
+        connect_module.__version__ = "2.2.9"
+        db_integration = dbapi.DatabaseApiIntegration(
+            "instrumenting_module_test_name",
+            "mysql",
+            enable_commenter=True,
+            connect_module=connect_module,
+        )
+        mock_cursor = mock.MagicMock()
+        mock_cursor._cnx._cmysql.get_client_info.side_effect = AttributeError(
+            "Primary method failed"
+        )
+        mock_cursor._connection._cmysql.get_client_info.side_effect = (
+            AttributeError("Fallback method failed")
+        )
+        mock_connection = db_integration.wrapped_connection(
+            mock_connect, {}, {}
+        )
+        cursor = mock_connection.cursor()
+        cursor._cnx = mock_cursor._cnx
+        cursor._connection = mock_cursor._connection
+        cursor.execute("SELECT 1;")
+        mock_cursor._cnx._cmysql.get_client_info.assert_called_once()
+        mock_cursor._connection._cmysql.get_client_info.assert_called_once()
+        mock_logger.debug.assert_called_once()
+        self.assertEqual(
+            db_integration.commenter_data["mysql_client_version"], "unknown"
+        )
+
 
 # pylint: disable=unused-argument
 def mock_connect(*args, **kwargs):

tests/opentelemetry-docker-tests/tests/mysql/test_mysql_sqlcommenter.py

@@ -0,0 +1,104 @@
+# Copyright 2025, OpenTelemetry Authors
+#
+# 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.
+
+import os
+
+import mysql.connector
+
+from opentelemetry.instrumentation.mysql import MySQLInstrumentor
+from opentelemetry.test.test_base import TestBase
+
+MYSQL_USER = os.getenv("MYSQL_USER", "testuser")
+MYSQL_PASSWORD = os.getenv("MYSQL_PASSWORD", "testpassword")
+MYSQL_HOST = os.getenv("MYSQL_HOST", "localhost")
+MYSQL_PORT = int(os.getenv("MYSQL_PORT", "3306"))
+MYSQL_DB_NAME = os.getenv("MYSQL_DB_NAME", "opentelemetry-tests")
+
+
+class TestFunctionalMySqlCommenter(TestBase):
+    def test_commenter_enabled_direct_reference(self):
+        MySQLInstrumentor().instrument(enable_commenter=True)
+        cnx = mysql.connector.connect(
+            user=MYSQL_USER,
+            password=MYSQL_PASSWORD,
+            host=MYSQL_HOST,
+            port=MYSQL_PORT,
+            database=MYSQL_DB_NAME,
+        )
+        cursor = cnx.cursor()
+
+        cursor.execute("SELECT 1;")
+        cursor.fetchall()
+        self.assertRegex(
+            cursor.statement,
+            r"SELECT 1 /\*db_driver='mysql\.connector[^']*',dbapi_level='\d\.\d',dbapi_threadsafety=\d,driver_paramstyle='[^']*',mysql_client_version='[^']*',traceparent='[^']*'\*/;",
+        )
+        self.assertRegex(
+            cursor.statement, r"mysql_client_version='(?!unknown)[^']+"
+        )
+
+        cursor.close()
+        cnx.close()
+        MySQLInstrumentor().uninstrument()
+
+    def test_commenter_enabled_connection_proxy(self):
+        cnx = mysql.connector.connect(
+            user=MYSQL_USER,
+            password=MYSQL_PASSWORD,
+            host=MYSQL_HOST,
+            port=MYSQL_PORT,
+            database=MYSQL_DB_NAME,
+        )
+        instrumented_cnx = MySQLInstrumentor().instrument_connection(
+            connection=cnx,
+            enable_commenter=True,
+        )
+        cursor = instrumented_cnx.cursor()
+
+        cursor.execute("SELECT 1;")
+        cursor.fetchall()
+        self.assertRegex(
+            cursor.statement,
+            r"SELECT 1 /\*db_driver='mysql\.connector[^']*',dbapi_level='\d\.\d',dbapi_threadsafety=\d,driver_paramstyle='[^']*',mysql_client_version='[^']*',traceparent='[^']*'\*/;",
+        )
+        self.assertRegex(
+            cursor.statement, r"mysql_client_version='(?!unknown)[^']+"
+        )
+
+        cursor.close()
+        MySQLInstrumentor().uninstrument_connection(instrumented_cnx)
+        cnx.close()
+
+    def test_commenter_mysql_client_version_fallback_to_unknown(self):
+        """Test that mysql_client_version falls back to 'unknown' with pure Python implementation"""
+        MySQLInstrumentor().instrument(enable_commenter=True)
+        cnx = mysql.connector.connect(
+            user=MYSQL_USER,
+            password=MYSQL_PASSWORD,
+            host=MYSQL_HOST,
+            port=MYSQL_PORT,
+            database=MYSQL_DB_NAME,
+            use_pure=True,  # Use pure Python - no _cmysql module
+        )
+        cursor = cnx.cursor()
+
+        cursor.execute("SELECT 1;")
+        cursor.fetchall()
+
+        # With use_pure=True, _cmysql is not available, should fall back to 'unknown'
+        self.assertRegex(cursor.statement, r"mysql_client_version='unknown'")
+
+        cursor.close()
+        cnx.close()
+        MySQLInstrumentor().uninstrument()