Only use feature if it's available

fastapi/_compat.py

@@ -147,6 +147,10 @@ if PYDANTIC_V2:
         ) -> Any:
             # What calls this code passes a value that already called
             # self._type_adapter.validate_python(value)
+            #
+            # context argument was introduced in pydantic 2.7.3
+            kwargs = {"context": context} if PYDANTIC_VERSION > "2.7.2" else {}
+
             return self._type_adapter.dump_python(
                 value,
                 mode=mode,
@@ -156,7 +160,7 @@ if PYDANTIC_V2:
                 exclude_unset=exclude_unset,
                 exclude_defaults=exclude_defaults,
                 exclude_none=exclude_none,
-                context=context,
+                **kwargs,
             )
 
         def __hash__(self) -> int:

tests/test_serialize_response_model.py

@@ -1,7 +1,9 @@
 from typing import Dict, List, Optional
 
+import pytest
 from fastapi import FastAPI
-from pydantic import BaseModel, Field
+from fastapi._compat import PYDANTIC_VERSION
+from pydantic import BaseModel, Field, SerializationInfo, model_serializer
 from starlette.testclient import TestClient
 
 app = FastAPI()
@@ -176,6 +178,7 @@ def test_validdict_exclude_unset():
     }
 
 
+@pytest.mark.skipif(PYDANTIC_VERSION < "2.7.2", reason="requires Pydantic 2.7.3+")
 def test_validdict_with_context():
     response = client.get("/items/validdict-with-context")
     response.raise_for_status()