Fix Pydantic v2 deprecation warning in json_adapter (#8263)

* Fix Pydantic v2 deprecation warning in json_adapter

* Fix json adapter tests

* use __config__ field

---------

Co-authored-by: chenmoneygithub <chen.qian@databricks.com>

Author: brishin

dspy/adapters/json_adapter.py

@@ -219,8 +219,8 @@ def _get_structured_outputs_response_format(signature: SignatureMeta) -> type[py
     # Build the model with extra fields forbidden.
     pydantic_model = pydantic.create_model(
         "DSPyProgramOutputs",
+        __config__=pydantic.ConfigDict(extra="forbid"),
         **fields,
-        __config__=type("Config", (), {"extra": "forbid"}),
     )
 
     # Generate the initial schema.

tests/adapters/test_json_adapter.py

@@ -58,7 +58,7 @@ class TestSignature(dspy.Signature):
         input1: str = dspy.InputField()
         output1: str = dspy.OutputField(desc="String output field")
 
-    dspy.configure(lm=dspy.LM(model="openai/gpt4o"), adapter=dspy.JSONAdapter())
+    dspy.configure(lm=dspy.LM(model="openai/gpt4o", cache=False), adapter=dspy.JSONAdapter())
     program = dspy.Predict(TestSignature)
     with mock.patch("litellm.completion") as mock_completion:
         mock_completion.side_effect = [Exception("Bad structured outputs!"), mock_completion.return_value]