fix(openai): avoid duplicated error check in with_structured_output with raw input

Author: Louis Auneau

libs/partners/openai/langchain_openai/chat_models/base.py

@@ -89,6 +89,7 @@
 from langchain_core.outputs import ChatGeneration, ChatGenerationChunk, ChatResult
 from langchain_core.runnables import (
     Runnable,
+    RunnableBranch,
     RunnableLambda,
     RunnableMap,
     RunnablePassthrough,
@@ -2215,8 +2216,12 @@ def _get_raw_structured_output_chain(
         parser_with_fallback = parser_assign.with_fallbacks(
             [parser_error_fallback], exception_key="parsing_error"
         )
+        branch = RunnableBranch[dict, dict](
+            (lambda x: x.get("parsing_error") is not None, RunnablePassthrough()),
+            parser_with_fallback,
+        )
 
-        return wrap_input | llm_with_fallback | parser_with_fallback
+        return wrap_input | llm_with_fallback | branch
 
     def _get_message_from_error_response(
         self, error: Exception

libs/partners/openai/tests/unit_tests/chat_models/test_base.py

@@ -3266,7 +3266,7 @@ def test_with_structured_output_validation_error() -> None:
         "usage": {"prompt_tokens": 10, "completion_tokens": 5, "total_tokens": 15},
     }
     mock_api_response = MagicMock(spec=APIResponse)
-    mock_api_response.http_response = MagicMock(spec=Response)
+    mock_api_response.http_response = MagicMock(spec=httpx.Response)
     mock_api_response.http_response.json.return_value = response_json
     mock_api_response.parse.side_effect = ValidationError.from_exception_data(
         title="Foo",