bytearray.resize() must not clear the object on error (memory allocation failure)

Python 3.15 reimplemented bytearray using an internal bytes object (to implement the bytearray.take_bytes() method). _PyBytes_Resize() is used internally to resize the bytearray object. Problem: if _PyBytes_Resize() fails, the bytearray object is cleared.

On Python 3.14, the bytearray is not cleared on resize failure.

The following example works on Python 3.14 but fails on Python 3.15.

import _testcapi

data = b'some data'
ba = bytearray(data)
try:
    try:
        _testcapi.set_nomemory(0)
        ba.resize(1024)
    except MemoryError:
        pass
    else:
        raise AssertionError("expect MemoryError")
finally:
    _testcapi.remove_mem_hooks()
if ba != data:
    raise AssertionError(f"{ba} != {data}")

Linked PRs

• gh-157243
• gh-157340
• gh-157344
• gh-157350
• gh-157351
• gh-157352
• gh-157371
• gh-157375
• gh-157431
• gh-157619
• gh-157723
• gh-157811

Start with the bytearray.resize() path and its use of _PyBytes_Resize(), then reproduce the provided _testcapi.set_nomemory() example. Done means a failed resize raises MemoryError while preserving the bytearray contents, with a regression test covering that behavior.