feat: implement make_default for PydanticSchema (jpmorganchase#64)

src/py_avro_schema/_schemas.py

@@ -567,6 +567,9 @@ def data(self, names: NamesType) -> JSONObj:
             "items": self.items_schema.data(names=names),
         }
 
+    def make_default(self, py_default: Any) -> Any:
+        return [_schema_obj(default.__class__).make_default(default) for default in py_default]
+
 
 class DictSchema(Schema):
     """An Avro map schema for a given Python mapping"""
@@ -807,10 +810,6 @@ def __init__(
             if isinstance(self.schema, UnionSchema):
                 self.schema.sort_item_schemas(self.default)
             typeguard.check_type(self.default, self.py_type)
-
-            # allow to use pydantic models as default values
-            if PydanticSchema.handles_type(default.__class__):
-                self.default = default.model_dump(mode="json")  # type: ignore
         else:
             if Option.DEFAULTS_MANDATORY in self.options:
                 raise TypeError(f"Default value for field {self} is missing")
@@ -906,6 +905,10 @@ def _record_field(self, name: str, py_field: pydantic.fields.FieldInfo) -> Recor
         )
         return field_obj
 
+    def make_default(self, py_default: Any) -> Any:
+        """Return an Avro schema compliant default value for a given Python value"""
+        return {key: _schema_obj(value.__class__).make_default(value) for key, value in py_default}
+
     def _annotation(self, field_name: str) -> Type:
         """
         Fetch the raw annotation for a given field name

tests/test_pydantic.py

@@ -531,6 +531,7 @@ class Default(pydantic.BaseModel):
 
     class PyType(pydantic.BaseModel):
         default: Default = pydantic.Field(..., default_factory=Default)
+        defaults: list[Default] = pydantic.Field(..., default_factory=lambda: [Default()])
 
     expected = {
         "fields": [
@@ -542,7 +543,8 @@ class PyType(pydantic.BaseModel):
                     "name": "Default",
                     "type": "record",
                 },
-            }
+            },
+            {"default": [{"field_a": "default_a"}], "name": "defaults", "type": {"items": "Default", "type": "array"}},
         ],
         "name": "PyType",
         "type": "record",