`_remote_debugging`: `BinaryWriter.write_sample()` trivial segfault

Bug report

Bug description:

[139] 2026-09-09T18:57:09.249268000+0200 maurycy@gimel /Users/maurycy/work/cpython (main 52ffffe) % ./python.exe 
Python 3.16.0a0 (heads/main:83dbe6ae9f4, Sep  6 2026, 18:18:16) [Clang 21.0.0 (clang-2100.1.1.101)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import _remote_debugging
>>> _remote_debugging.BinaryWriter("/tmp/o.bin", 1000, 1000000).write_sample([42], 2000)
zsh: segmentation fault  ./python.exe

There's many more variants, easy to come up with.

This is the place:

https://github.com/python/cpython/blob/52ffffe0a23bf0f4a57ee00377c5aeb965b3a29a/Modules/_remote_debugging/binary_io_writer.c#L1013

It only checks if it's a list, and then it trusts completely:

https://github.com/python/cpython/blob/52ffffe0a23bf0f4a57ee00377c5aeb965b3a29a/Modules/_remote_debugging/binary_io_writer.c#L841-L848

https://github.com/python/cpython/blob/52ffffe0a23bf0f4a57ee00377c5aeb965b3a29a/Modules/_remote_debugging/binary_io_writer.c#L928-L930

https://github.com/python/cpython/blob/52ffffe0a23bf0f4a57ee00377c5aeb965b3a29a/Modules/_remote_debugging/binary_io_writer.c#L1020-L1023

The comment says Use unchecked accessors since we control the data structures but I still think that segmentation fault on a public method is not great.

I will submit a PR soon.

ref #148178

CPython versions tested on:

CPython main branch

Operating systems tested on:

macOS

Linked PRs

• gh-157228

Bắt đầu trong Modules/_remote_debugging/binary_io_writer.c tại BinaryWriter.write_sample() và các vị trí unchecked-accessor được tham chiếu. Tái hiện sự cố bằng lệnh gọi BinaryWriter(...).write_sample([42], 2000) được cung cấp, sau đó xác minh rằng các đầu vào công khai không hợp lệ không còn gây ra segfault và hành vi này được bao phủ bởi các bài kiểm thử hồi quy phù hợp.