fix: use custom serializers for custom base model values

Author: heitorlessa

aws_lambda_powertools/event_handler/openapi/encoders.py

@@ -81,6 +81,7 @@ def jsonable_encoder(  # noqa: PLR0911
                 exclude_unset=exclude_unset,
                 exclude_none=exclude_none,
                 exclude_defaults=exclude_defaults,
+                custom_serializer=custom_serializer,
             )
 
         # Dataclasses
@@ -171,6 +172,7 @@ def _dump_base_model(
     exclude_unset: bool = False,
     exclude_none: bool = False,
     exclude_defaults: bool = False,
+    custom_serializer: Optional[Callable[[Any], str]] = None,
 ):
     """
     Dump a BaseModel object to a dict, using the same parameters as jsonable_encoder
@@ -192,6 +194,7 @@ def _dump_base_model(
         obj_dict,
         exclude_none=exclude_none,
         exclude_defaults=exclude_defaults,
+        custom_serializer=custom_serializer,
     )
 
 

tests/functional/event_handler/_pydantic/test_openapi_encoders.py

@@ -228,3 +228,28 @@ def serializer(value):
 
     # THEN we should get the custom serializer output
     assert result == ["serialized"]
+
+
+def test_openapi_encode_custom_serializer_pydantic():
+    # GIVEN a sequence with a custom class
+    class CustomClass:
+        __slots__ = []
+
+    class Order(BaseModel):
+        kind: CustomClass
+
+        # maintenance: deprecate in V3; becomes model_config =ConfigDict(<directive>=True)
+        class Config:
+            arbitrary_types_allowed = True
+
+    order = Order(kind=CustomClass())
+
+    # AND a custom serializer
+    def serializer(value):
+        return "serialized"
+
+    # WHEN we call jsonable_encoder with the nested dictionary and unserializable value
+    result = jsonable_encoder(order, custom_serializer=serializer)
+
+    # THEN we should get the custom serializer output
+    assert result == {"kind": "serialized"}