https://github.com/python/cpython/commit/cbf64e81b668c2bf2b8463afb4bcff1771998d1a commit: cbf64e81b668c2bf2b8463afb4bcff1771998d1a branch: main author: Cody Maloney <[email protected]> committer: DinoV <[email protected]> date: 2026-10-21T11:46:56-07:00 summary:
gh-144725: Relax over-strict alignment test on arrays (#157530) * gh-144725: Relax over-strict alignment test on arrays Co-authored-by: Jake Lishman <[email protected]> files: M Lib/test/test_buffer.py diff --git a/Lib/test/test_buffer.py b/Lib/test/test_buffer.py index 579e680448e94e..f42a71cea319b6 100644 --- a/Lib/test/test_buffer.py +++ b/Lib/test/test_buffer.py @@ -4519,24 +4519,18 @@ def test_bytearray_alignment(self): @support.cpython_only @unittest.skipIf(_testcapi is None, "requires _testcapi") def test_array_alignment(self): - # gh-140557: pointer alignment of buffers including empty allocation - # should match the maximum array alignment. - formats = [fmt for fmt in ARRAY - if struct.calcsize(fmt) <= struct.calcsize('P')] - align = max(struct.calcsize(fmt) for fmt in formats) - cases = [array.array(fmt) for fmt in formats] - # Empty arrays - self.assertEqual( - [_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) % align for case in cases], - [0] * len(cases), - ) + # gh-140557: buffer pointers, including for empty arrays, must be + # aligned to at least the alignment of the element type. + for fmt in ARRAY: + with self.subTest(fmt=fmt): + # Alignment can differ from size, for example 'Zd' on x86-64 + # has size 16 and alignment 8. Have calcsize add a single byte + # then pad until the alignment of the type but include zero + # instances. B = 1 byte, 0{fmt} = zero instances of fmt. + align = struct.calcsize(f"B0{fmt}") + for case in (array.array(fmt), array.array(fmt, [0])): + ptr = _testcapi.buffer_pointer_as_int(case) + self.assertEqual(ptr % align, 0) @support.cpython_only def test_pybuffer_size_from_format(self): _______________________________________________ Python-checkins mailing list -- [email protected] To unsubscribe send an email to [email protected] https://mail.python.org/mailman3//lists/python-checkins.python.org Member address: [email protected]
