Add support for ReadOnly from PEP 705

README.md

@@ -219,6 +219,7 @@ for special primitives from the [`typing`](https://docs.python.org/3/library/typ
 * [`Final`](https://docs.python.org/3/library/typing.html#typing.Final)
 * [`Self`](https://docs.python.org/3/library/typing.html#typing.Self)
 * [`Unpack`](https://docs.python.org/3/library/typing.html#typing.Unpack)
+* [`ReadOnly`](https://docs.python.org/3/library/typing.html#typing.ReadOnly)
 
 for standard interpreter types from [`types`](https://docs.python.org/3/library/types.html#standard-interpreter-types) module:
 * [`NoneType`](https://docs.python.org/3/library/types.html#types.NoneType)
@@ -279,6 +280,7 @@ for backported types from [`typing-extensions`](https://github.com/python/typing
 * [`Self`](https://docs.python.org/3/library/typing.html#typing.Self)
 * [`TypeVarTuple`](https://docs.python.org/3/library/typing.html#typing.TypeVarTuple)
 * [`Unpack`](https://docs.python.org/3/library/typing.html#typing.Unpack)
+* [`ReadOnly`](https://docs.python.org/3/library/typing.html#typing.ReadOnly)
 
 for arbitrary types:
 * [user-defined types](#user-defined-types)

mashumaro/core/meta/helpers.py

@@ -325,6 +325,15 @@ def is_typed_dict(typ: Type) -> bool:
     return False
 
 
+def is_readonly(typ: Type) -> bool:
+    origin = get_type_origin(typ)
+    for module in (typing, typing_extensions):
+        with suppress(AttributeError):
+            if origin is getattr(module, "ReadOnly"):
+                return True
+    return False
+
+
 def is_named_tuple(typ: Type) -> bool:
     try:
         return issubclass(typ, tuple) and hasattr(typ, "_fields")

mashumaro/core/meta/types/pack.py

@@ -33,6 +33,7 @@
     is_new_type,
     is_not_required,
     is_optional,
+    is_readonly,
     is_required,
     is_self,
     is_special_typing_primitive,
@@ -545,6 +546,8 @@ def pack_special_typing_primitive(spec: ValueSpec) -> Optional[Expression]:
                 return PackerRegistry.get(spec.copy(type=evaluated))
         elif is_type_alias_type(spec.type):
             return PackerRegistry.get(spec.copy(type=spec.type.__value__))
+        elif is_readonly(spec.type):
+            return PackerRegistry.get(spec.copy(type=get_args(spec.type)[0]))
         raise UnserializableDataError(
             f"{spec.type} as a field type is not supported by mashumaro"
         )

mashumaro/core/meta/types/unpack.py

@@ -44,6 +44,7 @@
     is_new_type,
     is_not_required,
     is_optional,
+    is_readonly,
     is_required,
     is_self,
     is_special_typing_primitive,
@@ -873,6 +874,8 @@ def unpack_special_typing_primitive(spec: ValueSpec) -> Optional[Expression]:
                 return UnpackerRegistry.get(spec.copy(type=evaluated))
         elif is_type_alias_type(spec.type):
             return UnpackerRegistry.get(spec.copy(type=spec.type.__value__))
+        elif is_readonly(spec.type):
+            return UnpackerRegistry.get(spec.copy(type=get_args(spec.type)[0]))
         raise UnserializableDataError(
             f"{spec.type} as a field type is not supported by mashumaro"
         )

mashumaro/jsonschema/schema.py

@@ -40,6 +40,7 @@
     is_named_tuple,
     is_new_type,
     is_not_required,
+    is_readonly,
     is_required,
     is_special_typing_primitive,
     is_type_var,
@@ -457,6 +458,8 @@ def on_special_typing_primitive(
         )
     elif is_type_var_tuple(instance.type):
         return get_schema(instance.derive(type=tuple[Any, ...]), ctx)
+    elif is_readonly(instance.type):
+        return get_schema(instance.derive(type=args[0]), ctx)
     elif isinstance(instance.type, ForwardRef):
         evaluated = evaluate_forward_ref(
             instance.type,

tests/entities.py

@@ -13,7 +13,7 @@ class StrEnum(str, Enum):
         pass
 
 
-from typing_extensions import NamedTuple, TypedDict, TypeVar
+from typing_extensions import NamedTuple, ReadOnly, TypedDict, TypeVar
 
 from mashumaro import DataClassDictMixin
 from mashumaro.config import TO_DICT_ADD_OMIT_NONE_FLAG, BaseConfig
@@ -254,6 +254,10 @@ class TypedDictOptionalKeysWithOptional(TypedDict, total=False):
     y: float
 
 
+class TypedDictWithReadOnly(TypedDict):
+    x: ReadOnly[int]
+
+
 class GenericTypedDict(TypedDict, Generic[T]):
     x: T
     y: int

tests/test_data_types.py

@@ -61,7 +61,11 @@
     SerializableType,
     SerializationStrategy,
 )
-from tests.entities import MyUntypedNamedTupleWithDefaults, TDefaultInt
+from tests.entities import (
+    MyUntypedNamedTupleWithDefaults,
+    TDefaultInt,
+    TypedDictWithReadOnly,
+)
 
 from .conftest import add_unpack_method
 from .entities import (
@@ -1197,6 +1201,15 @@ class DataClass(DataClassDictMixin):
     }
 
 
+def test_dataclass_with_typed_dict_with_read_only_key():
+    @dataclass
+    class DataClass(DataClassDictMixin):
+        x: TypedDictWithReadOnly
+
+    assert DataClass.from_dict({"x": {"x": "42"}}) == DataClass({"x": 42})
+    assert DataClass({"x": 42}).to_dict() == {"x": {"x": 42}}
+
+
 def test_dataclass_with_named_tuple():
     @dataclass
     class DataClass(DataClassDictMixin):

tests/test_jsonschema/test_jsonschema_generation.py

@@ -107,6 +107,7 @@
     TypedDictRequiredAndOptionalKeys,
     TypedDictRequiredKeys,
     TypedDictRequiredKeysWithOptional,
+    TypedDictWithReadOnly,
 )
 from tests.test_pep_655 import (
     TypedDictCorrectNotRequired,
@@ -721,6 +722,11 @@ def test_jsonschema_for_typeddict():
         additionalProperties=False,
         required=["required"],
     )
+    assert build_json_schema(TypedDictWithReadOnly) == JSONObjectSchema(
+        properties={"x": JSONSchema(type=JSONSchemaInstanceType.INTEGER)},
+        additionalProperties=False,
+        required=["x"],
+    )
 
 
 def test_jsonschema_for_mapping():