Add tests for CFieldInfo.

Author: ZeroIntensity

Lib/ctypes/util.py

@@ -516,9 +516,11 @@ def _process_struct(klass, /, *, align, layout, endian, pack):
         if get_origin(hint) is ClassVar:
             continue
 
-        field = [name, hint]
+        field = [name]
         if get_origin(hint) is Annotated:
-            field_info = get_args(hint)[1]
+            args = get_args(hint)
+            field.append(args[0])
+            field_info = args[1]
             if not isinstance(field_info, CFieldInfo):
                 raise TypeError(f"expected CFieldInfo in Annotated, got {field_info!r}")
 
@@ -527,8 +529,8 @@ def _process_struct(klass, /, *, align, layout, endian, pack):
 
             if field_info.anonymous is True:
                 anonymous.append(name)
-
-            continue
+        else:
+            field.append(hint)
 
         fields.append(field)
 

Lib/test/test_ctypes/test_anon.py

@@ -1,22 +1,32 @@
 import unittest
 import test.support
 from ctypes import c_int, Union, Structure, sizeof
+from ctypes.util import CFieldInfo, struct
+from typing import Annotated
 from ._support import StructCheckMixin
 
 
 class AnonTest(unittest.TestCase, StructCheckMixin):
 
-    def test_anon(self):
+    @test.support.subTests("use_struct_util", [False, True])
+    def test_anon(self, use_struct_util):
         class ANON(Union):
             _fields_ = [("a", c_int),
                         ("b", c_int)]
         self.check_union(ANON)
 
-        class Y(Structure):
-            _fields_ = [("x", c_int),
-                        ("_", ANON),
-                        ("y", c_int)]
-            _anonymous_ = ["_"]
+        if use_struct_util:
+            @struct
+            class Y:
+                x: c_int
+                _: Annotated[ANON, CFieldInfo(anonymous=True)]
+                y: c_int
+        else:
+            class Y(Structure):
+                _fields_ = [("x", c_int),
+                            ("_", ANON),
+                            ("y", c_int)]
+                _anonymous_ = ["_"]
         self.check_struct(Y)
 
         self.assertEqual(Y.a.offset, sizeof(c_int))

Lib/test/test_ctypes/test_bitfields.py

@@ -1,5 +1,6 @@
 import os
 import sys
+from typing import Annotated
 import unittest
 from ctypes import (CDLL, Structure, sizeof, POINTER, byref, alignment,
                     LittleEndianStructure, BigEndianStructure,
@@ -8,8 +9,9 @@
                     c_short, c_ushort, c_int, c_uint, c_long, c_ulong,
                     c_longlong, c_ulonglong,
                     Union)
+from ctypes.util import struct, CFieldInfo
 from test import support
-from test.support import import_helper
+from test.support import import_helper, subTests
 from ._support import StructCheckMixin
 _ctypes_test = import_helper.import_module("_ctypes_test")
 
@@ -126,11 +128,19 @@ def test_generic_checks(self):
         self.check_struct(BITS_msvc)
         self.check_struct(BITS_gcc)
 
-    def test_longlong(self):
-        class X(Structure):
-            _fields_ = [("a", c_longlong, 1),
-                        ("b", c_longlong, 62),
-                        ("c", c_longlong, 1)]
+    @subTests("use_struct_util", [False, True])
+    def test_longlong(self, use_struct_util):
+        if use_struct_util:
+            @struct
+            class X:
+                a: Annotated[c_longlong, CFieldInfo(bit_width=1)]
+                b: Annotated[c_longlong, CFieldInfo(bit_width=62)]
+                c: Annotated[c_longlong, CFieldInfo(bit_width=1)]
+        else:
+            class X(Structure):
+                _fields_ = [("a", c_longlong, 1),
+                            ("b", c_longlong, 62),
+                            ("c", c_longlong, 1)]
         self.check_struct(X)
 
         self.assertEqual(sizeof(X), sizeof(c_longlong))