Make inheritance and metaclass of ctypes better match reality (#12982)

stdlib/ctypes/__init__.pyi

@@ -10,13 +10,11 @@ from _ctypes import (
     _CanCastTo as _CanCastTo,
     _CArgObject as _CArgObject,
     _CData as _CData,
-    _CDataMeta as _CDataMeta,
+    _CDataType as _CDataType,
     _CField as _CField,
     _Pointer as _Pointer,
     _PointerLike as _PointerLike,
     _SimpleCData as _SimpleCData,
-    _StructUnionBase as _StructUnionBase,
-    _StructUnionMeta as _StructUnionMeta,
     addressof as addressof,
     alignment as alignment,
     byref as byref,
@@ -28,7 +26,7 @@ from _ctypes import (
 )
 from ctypes._endian import BigEndianStructure as BigEndianStructure, LittleEndianStructure as LittleEndianStructure
 from typing import Any, ClassVar, Generic, TypeVar
-from typing_extensions import TypeAlias
+from typing_extensions import Self, TypeAlias
 
 if sys.platform == "win32":
     from _ctypes import FormatError as FormatError, get_last_error as get_last_error, set_last_error as set_last_error
@@ -48,7 +46,7 @@ class ArgumentError(Exception): ...
 
 class CDLL:
     _func_flags_: ClassVar[int]
-    _func_restype_: ClassVar[_CData]
+    _func_restype_: ClassVar[_CDataType]
     _name: str
     _handle: int
     _FuncPtr: type[_FuncPointer]
@@ -91,15 +89,21 @@ class _NamedFuncPointer(_FuncPointer):
     __name__: str
 
 def CFUNCTYPE(
-    restype: type[_CData] | None, *argtypes: type[_CData], use_errno: bool = ..., use_last_error: bool = ...
+    restype: type[_CData | _CDataType] | None,
+    *argtypes: type[_CData | _CDataType],
+    use_errno: bool = ...,
+    use_last_error: bool = ...,
 ) -> type[_FuncPointer]: ...
 
 if sys.platform == "win32":
     def WINFUNCTYPE(
-        restype: type[_CData] | None, *argtypes: type[_CData], use_errno: bool = ..., use_last_error: bool = ...
+        restype: type[_CData | _CDataType] | None,
+        *argtypes: type[_CData | _CDataType],
+        use_errno: bool = ...,
+        use_last_error: bool = ...,
     ) -> type[_FuncPointer]: ...
 
-def PYFUNCTYPE(restype: type[_CData] | None, *argtypes: type[_CData]) -> type[_FuncPointer]: ...
+def PYFUNCTYPE(restype: type[_CData | _CDataType] | None, *argtypes: type[_CData | _CDataType]) -> type[_FuncPointer]: ...
 
 # Any type that can be implicitly converted to c_void_p when passed as a C function argument.
 # (bytes is not included here, see below.)
@@ -112,7 +116,7 @@ _CVoidConstPLike: TypeAlias = _CVoidPLike | bytes
 
 _CastT = TypeVar("_CastT", bound=_CanCastTo)
 
-def cast(obj: _CData | _CArgObject | int, typ: type[_CastT]) -> _CastT: ...
+def cast(obj: _CData | _CDataType | _CArgObject | int, typ: type[_CastT]) -> _CastT: ...
 def create_string_buffer(init: int | bytes, size: int | None = None) -> Array[c_char]: ...
 
 c_buffer = create_string_buffer
@@ -140,6 +144,8 @@ class c_char(_SimpleCData[bytes]):
 
 class c_char_p(_PointerLike, _SimpleCData[bytes | None]):
     def __init__(self, value: int | bytes | None = ...) -> None: ...
+    @classmethod
+    def from_param(cls, value: Any, /) -> Self | _CArgObject: ...
 
 class c_double(_SimpleCData[float]): ...
 class c_longdouble(_SimpleCData[float]): ...  # can be an alias for c_double
@@ -155,7 +161,11 @@ class c_uint(_SimpleCData[int]): ...  # can be an alias for c_ulong
 class c_ulong(_SimpleCData[int]): ...
 class c_ulonglong(_SimpleCData[int]): ...  # can be an alias for c_ulong
 class c_ushort(_SimpleCData[int]): ...
-class c_void_p(_PointerLike, _SimpleCData[int | None]): ...
+
+class c_void_p(_PointerLike, _SimpleCData[int | None]):
+    @classmethod
+    def from_param(cls, value: Any, /) -> Self | _CArgObject: ...
+
 class c_wchar(_SimpleCData[str]): ...
 
 c_int8 = c_byte
@@ -174,6 +184,8 @@ class c_uint64(_SimpleCData[int]): ...
 
 class c_wchar_p(_PointerLike, _SimpleCData[str | None]):
     def __init__(self, value: int | str | None = ...) -> None: ...
+    @classmethod
+    def from_param(cls, value: Any, /) -> Self | _CArgObject: ...
 
 class c_bool(_SimpleCData[bool]):
     def __init__(self, value: bool = ...) -> None: ...

stdlib/ctypes/wintypes.pyi

@@ -1,7 +1,7 @@
+from _ctypes import _CArgObject, _CField
 from ctypes import (
     Array,
     Structure,
-    _CField,
     _Pointer,
     _SimpleCData,
     c_byte,
@@ -21,8 +21,8 @@ from ctypes import (
     c_wchar,
     c_wchar_p,
 )
-from typing import TypeVar
-from typing_extensions import TypeAlias
+from typing import Any, TypeVar
+from typing_extensions import Self, TypeAlias
 
 BYTE = c_byte
 WORD = c_ushort
@@ -241,10 +241,16 @@ LPBYTE = PBYTE
 PBOOLEAN = PBYTE
 
 # LP_c_char
-class PCHAR(_Pointer[CHAR]): ...
+class PCHAR(_Pointer[CHAR]):
+    # this is inherited from ctypes.c_char_p, kind of.
+    @classmethod
+    def from_param(cls, value: Any, /) -> Self | _CArgObject: ...
 
 # LP_c_wchar
-class PWCHAR(_Pointer[WCHAR]): ...
+class PWCHAR(_Pointer[WCHAR]):
+    # inherited from ctypes.c_wchar_p, kind of
+    @classmethod
+    def from_param(cls, value: Any, /) -> Self | _CArgObject: ...
 
 # LP_c_void_p
 class PHANDLE(_Pointer[HANDLE]): ...