Fix partial support (#7)

Author: provinzkraut

litestar_django/dto.py

@@ -120,7 +120,7 @@ def get_field_constraints(cls, field: AnyField) -> KwargDefinition:
                 # fast path for known supported validators
                 # nullable fields do not support these constraints and for enum the
                 # constraint is defined implicitly by its values
-                if not field.null and "enum" not in constraints:
+                if not (field.null or "enum" in constraints or cls.config.partial):
                     if isinstance(validator, validators.MinValueValidator):
                         constraints["gt"] = validator.limit_value
                     elif isinstance(validator, validators.MinLengthValidator):

tests/test_dto_field_definitions.py

@@ -401,6 +401,26 @@ def test_constraints() -> None:
     )
 
 
+def test_no_len_constraints_on_partial() -> None:
+    dto_type = DjangoModelDTO[Annotated[ModelWithFields, DjangoDTOConfig(partial=True)]]
+    field_defs = {
+        f.name: f for f in dto_type.generate_field_definitions(ModelWithFields)
+    }
+
+    assert field_defs["min_1_int_field"] == DTOFieldDefinition.from_field_definition(
+        model_name="ModelWithFields",
+        default_factory=None,
+        dto_field=DTOField(),
+        field_definition=FieldDefinition.from_annotation(
+            int,
+            name="min_1_int_field",
+            kwarg_definition=KwargDefinition(
+                title="min 1 int field",
+            ),
+        ),
+    )
+
+
 def test_nullable_field() -> None:
     dto_type = DjangoModelDTO[ModelWithFields]
     field_defs = {

tests/test_dto_integration.py

@@ -174,6 +174,26 @@ def handler(data: Author) -> Author:
         assert res.json() == {"id": author.id, "name": author_name, "books": []}
 
 
+@pytest.mark.django_db(transaction=True)
+def test_validate_partial() -> None:
+    @post(
+        "/",
+        sync_to_thread=True,
+        dto=DjangoModelDTO[Annotated[Author, DTOConfig(partial=True)]],
+        return_dto=DjangoModelDTO[Author],
+    )
+    def handler(data: Author) -> Author:
+        data.save()
+        return Author.objects.prefetch_related("books").get(id=data.id)
+
+    with create_test_client([handler]) as client:
+        author_name = secrets.token_hex()
+        res = client.post("/", json={"name": author_name})
+        assert res.status_code == 201
+        author = Author.objects.get(name=author_name)
+        assert res.json() == {"id": author.id, "name": author_name, "books": []}
+
+
 @pytest.mark.django_db(transaction=True)
 def test_enumfields() -> None:
     @post(