Bypass field validation on model instantiation if it does not contain…

… a default= argument

Makefile

@@ -1,34 +1,45 @@
- DJANGO_SETTINGS_MODULE ?= "tests.settings.django_test_settings"
-
-.PHONY: install build test lint upload upload-test clean
+export DJANGO_SETTINGS_MODULE=tests.settings.django_test_settings
 
+.PHONY: install
 install:
 	python3 -m pip install build twine
 	python3 -m pip install -e .[dev,test]
 
+.PHONY: build
 build:
 	python3 -m build
 
+.PHONY: migrations
 migrations:
 	python3 -m django makemigrations --noinput
 
+.PHONY: runserver
 runserver:
 	python3 -m django migrate && \
 	python3 -m django runserver
 
+.PHONY: check
+check:
+	python3 -m django check
+
+.PHONY: test
 test: A=
 test:
 	pytest $(A)
 
+.PHONY: lint
 lint: A=.
 lint:
 	python3 -m mypy $(A)
 
+.PHONY: upload
 upload:
 	python3 -m twine upload dist/*
 
+.PHONY: upload-test
 upload-test:
 	python3 -m twine upload --repository testpypi dist/*
 
+.PHONY: clean
 clean:
 	rm -rf dist/*

django_pydantic_field/v1/fields.py

@@ -34,7 +34,9 @@ def contribute_to_class(self, cls, name, *args, **kwargs):
     field: "PydanticSchemaField"
 
     def __set__(self, obj, value):
-        obj.__dict__[self.field.attname] = self.field.to_python(value)
+        if self.field.has_default() or value is not None:
+            value = self.field.to_python(value)
+        obj.__dict__[self.field.attname] = value
 
 
 class PydanticSchemaField(JSONField, t.Generic[base.ST]):

django_pydantic_field/v2/fields.py

@@ -60,11 +60,13 @@ def __set_name__(self, owner, name):
         self.field.adapter.bind(owner, name)
 
     def __set__(self, obj, value):
-        obj.__dict__[self.field.attname] = self.field.to_python(value)
+        if self.field.has_default() or value is not None:
+            value = self.field.to_python(value)
+        obj.__dict__[self.field.attname] = value
 
 
 class PydanticSchemaField(JSONField, ty.Generic[types.ST]):
-    descriptor_class: type[DeferredAttribute] = SchemaAttribute
+    descriptor_class: ty.ClassVar[type[DeferredAttribute]] = SchemaAttribute
     adapter: types.SchemaAdapter
 
     def __init__(
@@ -118,7 +120,8 @@ def check(self, **kwargs: ty.Any) -> list[checks.CheckMessage]:
 
         try:
             # Test that the default value conforms to the schema.
-            self.get_prep_value(self.get_default())
+            if self.has_default():
+                self.get_prep_value(self.get_default())
         except pydantic.ValidationError as exc:
             message = f"Default value cannot be adapted to the schema. Pydantic error: \n{str(exc)}"
             performed_checks.append(checks.Error(message, obj=self, id="pydantic.E002"))