Problem when ISO-2022-JP-MS is specified in mb_encode_mimeheader

[nanasess]

Description

PHP8.0.x or earlier will decode correctly, but PHP8.1.x will output undecoded strings.

The following code:

<?php

echo mb_decode_mimeheader(mb_encode_mimeheader('１２３４５６７８９０１２３４５６７８９０１２', 'ISO-2022-JP-MS', 'B'));

Resulted in this output:

１２３４５６７８９０１２３４５６７８#9#0#1#2

But I expected this output instead:

１２３４５６７８９０１２３４５６７８９０１２

PHP Version

PHP 8.1.6

Operating System

Ubuntu 20.04

[cmb69]

Indeed, there is something wrong in PHP 8.1: https://3v4l.org/ucPUC

[alexdowad]

@nanasess, thank you for reporting this problem! And as always, many thanks for @cmb69 and @Girgias for handling triage of incoming bug reports.

Interestingly, I have already fixed this problem in PHP-8.2+, in f3c8efd. However, the bug fix needs to be backported to PHP-8.1.

Let me work on that.

[alexdowad]

I am also adding a regression test for this.