Initial support for PEP 696

mashumaro/core/meta/helpers.py

@@ -272,7 +272,9 @@ def type_name(
             )
             return f"{_typing_name('Union', short)}[{args_str}]"
         else:
-            bound = getattr(typ, "__bound__")
+            bound = getattr(typ, "__default__", None)
+            if bound is None:
+                bound = getattr(typ, "__bound__")
             return type_name(bound, short, resolved_type_params)
     elif is_new_type(typ) and not PY_310_MIN:
         # because __qualname__ and __module__ are messed up
@@ -421,6 +423,8 @@ def is_type_var_any(typ: Type) -> bool:
         return False
     elif typ.__bound__ not in (None, Any):
         return False
+    elif getattr(typ, "__default__", None) not in (None, NoneType):
+        return False
     else:
         return True
 

mashumaro/core/meta/types/pack.py

@@ -458,7 +458,9 @@ def pack_special_typing_primitive(spec: ValueSpec) -> Optional[Expression]:
             if constraints:
                 return pack_union(spec, constraints, "type_var")
             else:
-                bound = getattr(spec.type, "__bound__")
+                bound = getattr(spec.type, "__default__", None)
+                if bound is None:
+                    bound = getattr(spec.type, "__bound__")
                 # act as if it was Optional[bound]
                 pv = PackerRegistry.get(spec.copy(type=bound))
                 return expr_or_maybe_none(spec, pv)

mashumaro/core/meta/types/unpack.py

@@ -741,7 +741,9 @@ def unpack_special_typing_primitive(spec: ValueSpec) -> Optional[Expression]:
             if constraints:
                 return TypeVarUnpackerBuilder(constraints).build(spec)
             else:
-                bound = getattr(spec.type, "__bound__")
+                bound = getattr(spec.type, "__default__", None)
+                if bound is None:
+                    bound = getattr(spec.type, "__bound__")
                 # act as if it was Optional[bound]
                 uv = UnpackerRegistry.get(spec.copy(type=bound))
                 return expr_or_maybe_none(spec, uv)

tests/entities.py

@@ -3,7 +3,7 @@
 from datetime import date, datetime
 from enum import Enum, Flag, IntEnum, IntFlag
 from os import PathLike
-from typing import Any, Generic, List, NewType, Optional, TypeVar, Union
+from typing import Any, Generic, List, NewType, Optional, Union
 
 try:
     from enum import StrEnum
@@ -13,7 +13,7 @@ class StrEnum(str, Enum):
         pass
 
 
-from typing_extensions import NamedTuple, TypedDict
+from typing_extensions import NamedTuple, TypedDict, TypeVar
 
 from mashumaro import DataClassDictMixin
 from mashumaro.config import TO_DICT_ADD_OMIT_NONE_FLAG, BaseConfig
@@ -22,6 +22,7 @@ class StrEnum(str, Enum):
 T = TypeVar("T")
 TAny = TypeVar("TAny", bound=Any)
 TInt = TypeVar("TInt", bound=int)
+TDefaultInt = TypeVar("TDefaultInt", default=int)
 TIntStr = TypeVar("TIntStr", int, str)
 T_Optional_int = TypeVar("T_Optional_int", bound=Optional[int])
 

tests/test_meta.py

@@ -70,6 +70,7 @@
     MyUntypedNamedTuple,
     T,
     TAny,
+    TDefaultInt,
     TInt,
     TIntStr,
 )
@@ -165,7 +166,10 @@ def test_is_dataclass_dict_mixin_subclass():
 
 
 def test_is_type_var_any():
+    assert is_type_var_any(T)
     assert is_type_var_any(TAny)
+    assert not is_type_var_any(TInt)
+    assert not is_type_var_any(TDefaultInt)
     assert not is_type_var_any(typing.Any)
     assert not is_type_var_any(TMyDataClass)
 
@@ -180,6 +184,7 @@ def test_is_type_var_any_list_38():
 def test_type_name():
     assert type_name(TAny) == "typing.Any"
     assert type_name(TInt) == "int"
+    assert type_name(TDefaultInt) == "int"
     assert type_name(TMyDataClass) == "tests.entities.MyDataClass"
     assert type_name(TIntStr) == "typing.Union[int, str]"
     assert type_name(typing.List[TInt]) == "typing.List[int]"
@@ -285,6 +290,7 @@ def test_type_name_pep_585():
 def test_type_name_short():
     assert type_name(TAny, short=True) == "Any"
     assert type_name(TInt, short=True) == "int"
+    assert type_name(TDefaultInt, short=True) == "int"
     assert type_name(TMyDataClass, short=True) == "MyDataClass"
     assert type_name(TIntStr, short=True) == "Union[int, str]"
     assert type_name(typing.List[TInt], short=True) == "List[int]"