fix(input): use None as default for Maybe fields instead of UNSET (#824)

Author: bellini666

strawberry_django/type.py

@@ -27,6 +27,7 @@
 from strawberry.types.base import WithStrawberryObjectDefinition
 from strawberry.types.cast import get_strawberry_type_cast
 from strawberry.types.field import StrawberryField
+from strawberry.types.maybe import _annotation_is_maybe  # noqa: PLC2701
 from strawberry.types.private import is_private
 from strawberry.utils.deprecations import DeprecatedDescriptor
 from typing_extensions import Self, dataclass_transform, get_annotations
@@ -165,18 +166,22 @@ def _process_type(
         # FIXME: For input types it is important to set the default value to UNSET
         # Is there a better way of doing this?
         if is_input:
+            # For Maybe types, the default should be None (matching strawberry's behavior)
+            # For other types, the default should be UNSET
+            is_maybe = _annotation_is_maybe(annotation)
+            default_value = None if is_maybe else UNSET
+
             # First check if the field is defined in the class. If it is,
-            # then we just need to set its default value to UNSET in case
-            # it is MISSING
+            # then we just need to set its default value in case it is MISSING
             if field_name in cls.__dict__:
                 field = cls.__dict__[field_name]
                 if (
                     isinstance(field, dataclasses.Field)
                     and field.default is dataclasses.MISSING
                 ):
-                    field.default = UNSET
+                    field.default = default_value
                     if isinstance(field, StrawberryField):
-                        field.default_value = UNSET
+                        field.default_value = default_value
 
                 continue
 
@@ -185,12 +190,12 @@ def _process_type(
                 if base_field is not None and isinstance(base_field, StrawberryField):
                     new_field = copy.copy(base_field)
                 else:
-                    new_field = _field(default=UNSET)
+                    new_field = _field(default=default_value)
 
                 cls_annotations[field_name] = field_annotation.raw_annotation
-                new_field.default = UNSET
+                new_field.default = default_value
                 if isinstance(base_field, StrawberryField):
-                    new_field.default_value = UNSET
+                    new_field.default_value = default_value
 
                 setattr(cls, field_name, new_field)
 

tests/types2/test_input.py

@@ -1,9 +1,11 @@
+import dataclasses
 from typing import cast
 
 import strawberry
 from strawberry import auto
 from strawberry.types import get_object_definition
 from strawberry.types.base import StrawberryOptional
+from strawberry.types.maybe import Maybe
 
 import strawberry_django
 
@@ -113,3 +115,27 @@ class Input(Base):
         ),
         ("another_name", StrawberryOptional(strawberry_django.OneToManyInput)),
     ]
+
+
+def test_maybe_field_default_value():
+    @strawberry_django.input(TypeModel)
+    class InputWithMaybe:
+        my_maybe_field: Maybe[bool]
+        regular_optional_field: str | None
+
+    @strawberry.input
+    class StrawberryInputWithMaybe:
+        my_maybe_field: Maybe[bool]
+
+    django_fields = {f.name: f for f in dataclasses.fields(InputWithMaybe)}
+    strawberry_fields = {
+        f.name: f for f in dataclasses.fields(StrawberryInputWithMaybe)
+    }
+
+    assert django_fields["my_maybe_field"].default is None
+    assert (
+        django_fields["my_maybe_field"].default
+        == strawberry_fields["my_maybe_field"].default
+    )
+
+    assert django_fields["regular_optional_field"].default is strawberry.UNSET