Hangup when printing empty string to unbuffered stdout

Crash report

What happened?

$ sudo python3 -u -c 'print(""); print("foo")'
Hangup

When printing an empty string to unbuffered stdout, under certain circumstances (e.g. when running on AIX under sudo, screen, tmux), the user session including the Python interpreter will terminate.

CPython versions tested on:

CPython main branch

Operating systems tested on:

Other

Output from running 'python -VV' on the command line:

Python 3.12.13 (main, Mar 6 2026, 03:56:12) [GCC 10.3.0]

Linked PRs

• gh-148774

首先使用未緩衝的 stdout 重現回報的命令，著重於 issue 中描述的 AIX、sudo、screen 和 tmux 情況。檢視連結的 PR gh-148774，以及其中指出的相關 CPython stdout/write 路徑。完成的標準是該命令不再終止使用者工作階段，且該行為由適當的回歸測試涵蓋。