Slacken test to match 'size_t' only

Author: jakelishman

Lib/test/test_buffer.py

@@ -4449,38 +4449,38 @@ def test_bytearray_release_buffer_read_flag(self):
 
     @support.cpython_only
     @unittest.skipIf(_testcapi is None, "requires _testcapi")
-    @unittest.skipIf(ctypes is None, "requires ctypes")
+    @unittest.skipIf(struct is None, "requires struct")
     def test_bytearray_alignment(self):
         # gh-140557: pointer alignment of buffers including empty allocation
-        max_align = ctypes.alignment(ctypes.c_longdouble)
+        # should be at least to `size_t`.
+        align = struct.calcsize("N")
         cases = [
             bytearray(),
             bytearray(1),
             bytearray(b"0123456789abcdef"),
             bytearray(16),
         ]
         ptrs = [_testcapi.buffer_pointer_as_int(array) for array in cases]
-        self.assertEqual([ptr % max_align for ptr in ptrs], [0]*len(ptrs))
+        self.assertEqual([ptr % align for ptr in ptrs], [0]*len(ptrs))
 
     @support.cpython_only
     @unittest.skipIf(_testcapi is None, "requires _testcapi")
-    @unittest.skipIf(ctypes is None, "requires ctypes")
+    @unittest.skipIf(struct is None, "requires struct")
     def test_array_alignment(self):
         # gh-140557: pointer alignment of buffers including empty allocation
-        max_align = ctypes.alignment(ctypes.c_longdouble)
+        # should be at least to `size_t`.
+        align = struct.calcsize("N")
         cases = [array.array(fmt) for fmt in ARRAY]
         # Empty arrays
         self.assertEqual(
-            [_testcapi.buffer_pointer_as_int(case) % max_align
-             for case in cases],
+            [_testcapi.buffer_pointer_as_int(case) % align for case in cases],
             [0] * len(cases),
         )
         for case in cases:
             case.append(0)
         # Allocated arrays
         self.assertEqual(
-            [_testcapi.buffer_pointer_as_int(case) % max_align
-             for case in cases],
+            [_testcapi.buffer_pointer_as_int(case) % align for case in cases],
             [0] * len(cases),
         )
 

Misc/NEWS.d/next/Core_and_Builtins/2025-10-24-17-30-51.gh-issue-140557.X2GETk.rst

@@ -1,2 +1,2 @@
-:func:`bytearray` and :func:`array.array` now default to aligned buffers when
-empty.  Unaligned buffers can still be created by slicing.
+:func:`bytearray` and :func:`array.array` buffers now have the same alignment
+when empty as when allocated. Unaligned buffers can still be created by slicing.