iconv(): Wrong encoding, conversion from "ASCII" to "UTF-8//IGNORE" is not allowed

[danielmarschall]

Hello,

I noticed that there is an incompatibility with the mbstring polyfill and PHP 8.1 / Alpine Linux,
which breaks a lot of my projects as soon as the php81-mbstring is not installed, but php81-iconv is installed:

Example:

Warning: iconv(): Wrong encoding, conversion from "ASCII" to "UTF-8//IGNORE" is not allowed in phar:///var/www/localhost/htdocs/phpstan.phar/vendor/symfony/polyfill-mbstring/Mbstring.php on line 736

It looks like //IGNORE is not accepted since echo iconv('UTF-8', 'UTF-8', 'test'); works, while echo iconv('UTF-8', 'UTF-8//IGNORE', 'test'); doesn't

[derrabus]

iconv on Alpine is really broken. You should consider installing ext-mbstring.

[jdreesen]

See also: docker-library/php#240