genai: fix function_utils to parse object/array json schemas properly (…

…#715)

libs/genai/langchain_google_genai/_function_utils.py

@@ -301,10 +301,18 @@ def _get_properties_from_schema(schema: Dict) -> Dict[str, Any]:
             continue
         properties_item: Dict[str, Union[str, int, Dict, List]] = {}
         if v.get("type") or v.get("anyOf") or v.get("type_"):
-            properties_item["type_"] = _get_type_from_schema(v)
+            item_type_ = _get_type_from_schema(v)
+            properties_item["type_"] = item_type_
             if _is_nullable_schema(v):
                 properties_item["nullable"] = True
 
+            # Replace `v` with chosen definition for array / object json types
+            any_of_types = v.get("anyOf")
+            if any_of_types and item_type_ in [glm.Type.ARRAY, glm.Type.OBJECT]:
+                json_type_ = "array" if item_type_ == glm.Type.ARRAY else "object"
+                # Use Index -1 for consistency with `_get_nullable_type_from_schema`
+                v = [val for val in any_of_types if val.get("type") == json_type_][-1]
+
         if v.get("enum"):
             properties_item["enum"] = v["enum"]
 

libs/genai/tests/unit_tests/test_function_utils.py

@@ -84,11 +84,6 @@ def possibly_none_list(
     # Convert to OpenAI tool
     oai_tool = convert_to_openai_tool(possibly_none_list)
 
-    # Manually assign the 'items' type in the parameters
-    oai_tool["function"]["parameters"]["properties"]["items"]["items"] = {
-        "type": "string"
-    }
-
     # Convert to GenAI, then to dict
     genai_tool = convert_to_genai_function_declarations([oai_tool])
     genai_tool_dict = tool_to_dict(genai_tool)