Add Disable Fallback Option in ChatAdapter (#8984)

Author: Ziems

dspy/adapters/chat_adapter.py

@@ -26,6 +26,20 @@ class FieldInfoWithName(NamedTuple):
 
 
 class ChatAdapter(Adapter):
+    def __init__(
+        self,
+        callbacks=None,
+        use_native_function_calling: bool = False,
+        native_response_types=None,
+        use_json_adapter_fallback: bool = True,
+    ):
+        super().__init__(
+            callbacks=callbacks,
+            use_native_function_calling=use_native_function_calling,
+            native_response_types=native_response_types,
+        )
+        self.use_json_adapter_fallback = use_json_adapter_fallback
+
     def __call__(
         self,
         lm: LM,
@@ -40,9 +54,13 @@ def __call__(
             # fallback to JSONAdapter
             from dspy.adapters.json_adapter import JSONAdapter
 
-            if isinstance(e, ContextWindowExceededError) or isinstance(self, JSONAdapter):
-                # On context window exceeded error or already using JSONAdapter, we don't want to retry with a different
-                # adapter.
+            if (
+                isinstance(e, ContextWindowExceededError)
+                or isinstance(self, JSONAdapter)
+                or not self.use_json_adapter_fallback
+            ):
+                # On context window exceeded error, already using JSONAdapter, or use_json_adapter_fallback is False
+                # we don't want to retry with a different adapter. Raise the original error instead of the fallback error.
                 raise e
             return JSONAdapter()(lm, lm_kwargs, signature, demos, inputs)
 
@@ -60,9 +78,13 @@ async def acall(
             # fallback to JSONAdapter
             from dspy.adapters.json_adapter import JSONAdapter
 
-            if isinstance(e, ContextWindowExceededError) or isinstance(self, JSONAdapter):
-                # On context window exceeded error or already using JSONAdapter, we don't want to retry with a different
-                # adapter.
+            if (
+                isinstance(e, ContextWindowExceededError)
+                or isinstance(self, JSONAdapter)
+                or not self.use_json_adapter_fallback
+            ):
+                # On context window exceeded error, already using JSONAdapter, or use_json_adapter_fallback is False
+                # we don't want to retry with a different adapter. Raise the original error instead of the fallback error.
                 raise e
             return await JSONAdapter().acall(lm, lm_kwargs, signature, demos, inputs)
 

tests/adapters/test_chat_adapter.py

@@ -442,6 +442,23 @@ def test_chat_adapter_fallback_to_json_adapter_on_exception():
         result = adapter(lm, {}, signature, [], {"question": "What is the capital of France?"})
         assert result == [{"answer": "Paris"}]
 
+def test_chat_adapter_respects_use_json_adapter_fallback_flag():
+    signature = dspy.make_signature("question->answer")
+    adapter = dspy.ChatAdapter(use_json_adapter_fallback=False)
+
+    with mock.patch("litellm.completion") as mock_completion:
+        mock_completion.return_value = ModelResponse(
+            choices=[Choices(message=Message(content="nonsense"))],
+            model="openai/gpt-4o-mini",
+        )
+
+        lm = dspy.LM("openai/gpt-4o-mini", cache=False)
+
+        with mock.patch("dspy.adapters.json_adapter.JSONAdapter.__call__") as mock_json_adapter_call:
+            with pytest.raises(dspy.utils.exceptions.AdapterParseError):
+                adapter(lm, {}, signature, [], {"question": "What is the capital of France?"})
+        mock_json_adapter_call.assert_not_called()
+
 
 @pytest.mark.asyncio
 async def test_chat_adapter_fallback_to_json_adapter_on_exception_async():