Segmentation fault when unicode characters are used in readline prompt

[Chi-teck]

Description

<?php

setlocale(LC_ALL, 'C');
readline('➤');

PHP Version

PHP 8.1.7

Operating System

Debian

[damianwadley]

With the non-debug PHP 7.4 I have on hand,

(gdb) bt
#0  0x00007ffff3c846e5 in ?? () from /usr/lib/x86_64-linux-gnu/libedit.so.2
#1  0x00007ffff3c858db in ?? () from /usr/lib/x86_64-linux-gnu/libedit.so.2
#2  0x00007ffff3c84e57 in ?? () from /usr/lib/x86_64-linux-gnu/libedit.so.2
#3  0x00007ffff3c85258 in el_wgets () from /usr/lib/x86_64-linux-gnu/libedit.so.2
#4  0x00007ffff3c7fd63 in el_gets () from /usr/lib/x86_64-linux-gnu/libedit.so.2
#5  0x00007ffff3c93486 in readline () from /usr/lib/x86_64-linux-gnu/libedit.so.2
#6  0x00007ffff3cb0762 in ?? () from /usr/lib/php/20190902/readline.so

Searching around, it seems there might be some issues with libedit - doesn't seem like the bug is with PHP itself:
https://bugs.mysql.com/bug.php?id=89359
https://github.com/racket/racket/issues/3223

See also:
https://bugs.php.net/bug.php?id=81280
https://bugs.php.net/bug.php?id=76989

[cmb69]

Are you using libreadline or libeditline? Which version? See READLINE_LIB and the phpinfo() output.

[Chi-teck]

Readline library => EditLine wrapper

[cmb69]

Thank you! While I cannot reproduce a segfault when building against libreadline-dev, I can when building against libedit-dev (3.1-20181209-1). As @damianwadley already said, this doesn't appear to be a PHP issue, though, but rather an issue with libedit.

[krakjoe]

Prior conversations:

• Fix bug #81280 refuse to allow unicode chars in prompts #7333 (context)
• Fix bug #81598: Use C.UTF-8 as LC_CTYPE locale by default #7635 (eventual fix)

This issue is (I think) fixed in 8.1 by 7635.

[cmb69]

Well, the issue is not fixed if you explicitly set the C locale; but as has been pointed out before, this is likely an issue with libedit.