SEA Session Configuration Fix: Explicitly convert values to str (#620)

* explicitly convert session conf values to str

Signed-off-by: varun-edachali-dbx <varun.edachali@databricks.com>

* add unit test for filter_session_conf

Signed-off-by: varun-edachali-dbx <varun.edachali@databricks.com>

* re-introduce unit test for string values of session conf

Signed-off-by: varun-edachali-dbx <varun.edachali@databricks.com>

* ensure Dict return from _filter_session_conf

Signed-off-by: varun-edachali-dbx <varun.edachali@databricks.com>

---------

Signed-off-by: varun-edachali-dbx <varun.edachali@databricks.com>

Author: varun-edachali-dbx

src/databricks/sql/backend/sea/backend.py

@@ -50,17 +50,17 @@
 
 
 def _filter_session_configuration(
-    session_configuration: Optional[Dict[str, str]]
-) -> Optional[Dict[str, str]]:
+    session_configuration: Optional[Dict[str, Any]],
+) -> Dict[str, str]:
     if not session_configuration:
-        return None
+        return {}
 
     filtered_session_configuration = {}
     ignored_configs: Set[str] = set()
 
     for key, value in session_configuration.items():
         if key.upper() in ALLOWED_SESSION_CONF_TO_DEFAULT_VALUES_MAP:
-            filtered_session_configuration[key.lower()] = value
+            filtered_session_configuration[key.lower()] = str(value)
         else:
             ignored_configs.add(key)
 
@@ -188,7 +188,7 @@ def max_download_threads(self) -> int:
 
     def open_session(
         self,
-        session_configuration: Optional[Dict[str, str]],
+        session_configuration: Optional[Dict[str, Any]],
         catalog: Optional[str],
         schema: Optional[str],
     ) -> SessionId:

tests/unit/test_sea_backend.py

@@ -624,6 +624,71 @@ def test_utility_methods(self, sea_client):
         assert description[1][1] == "INT"  # type_code
         assert description[1][6] is False  # null_ok
 
+    def test_filter_session_configuration(self):
+        """Test that _filter_session_configuration converts all values to strings."""
+        session_config = {
+            "ANSI_MODE": True,
+            "statement_timeout": 3600,
+            "TIMEZONE": "UTC",
+            "enable_photon": False,
+            "MAX_FILE_PARTITION_BYTES": 128.5,
+            "unsupported_param": "value",
+            "ANOTHER_UNSUPPORTED": 42,
+        }
+
+        result = _filter_session_configuration(session_config)
+
+        # Verify result is not None
+        assert result is not None
+
+        # Verify all returned values are strings
+        for key, value in result.items():
+            assert isinstance(
+                value, str
+            ), f"Value for key '{key}' is not a string: {type(value)}"
+
+        # Verify specific conversions
+        expected_result = {
+            "ansi_mode": "True",  # boolean True -> "True", key lowercased
+            "statement_timeout": "3600",  # int -> "3600", key lowercased
+            "timezone": "UTC",  # string -> "UTC", key lowercased
+            "enable_photon": "False",  # boolean False -> "False", key lowercased
+            "max_file_partition_bytes": "128.5",  # float -> "128.5", key lowercased
+        }
+
+        assert result == expected_result
+
+        # Test with None input
+        assert _filter_session_configuration(None) == {}
+
+        # Test with only unsupported parameters
+        unsupported_config = {
+            "unsupported_param1": "value1",
+            "unsupported_param2": 123,
+        }
+        result = _filter_session_configuration(unsupported_config)
+        assert result == {}
+
+        # Test case insensitivity for keys
+        case_insensitive_config = {
+            "ansi_mode": "false",  # lowercase key
+            "STATEMENT_TIMEOUT": 7200,  # uppercase key
+            "TiMeZoNe": "America/New_York",  # mixed case key
+        }
+        result = _filter_session_configuration(case_insensitive_config)
+        expected_case_result = {
+            "ansi_mode": "false",
+            "statement_timeout": "7200",
+            "timezone": "America/New_York",
+        }
+        assert result == expected_case_result
+
+        # Verify all values are strings in case insensitive test
+        for key, value in result.items():
+            assert isinstance(
+                value, str
+            ), f"Value for key '{key}' is not a string: {type(value)}"
+
     def test_results_message_to_execute_response_is_staging_operation(self, sea_client):
         """Test that is_staging_operation is correctly set from manifest.is_volume_operation."""
         # Test when is_volume_operation is True