[BUG] php-iconv extension is still a problem on alpine

[mikespub]

Is there an existing issue for this?

• I have searched the existing issues

Current Behavior

With this base image and its derivatives, PHP packages like symfony/string that rely on the php-iconv extension internally still generate wrong output, e.g. when trying to convert Chinese to Ascii.

See https://gitlab.alpinelinux.org/alpine/aports/-/issues/15114 for details and context.

Expected Behavior

Convert strings correctly :-)

I assume that you'll prefer to wait for alpine's php-iconv package to work correctly someday, rather than try & fix this yourself, but at least we have a track of the issue here...
Adding the alpine package icu-data-full fixes the issue (but increases the image size).

Steps To Reproduce

$ composer require symfony/string
$ apk --no-cache add vim # use vim to edit utf-8 files
$ vim test.php

<?php

require_once __DIR__ . '/vendor/autoload.php';

// Sūnzǐ bīngfǎ = Sun Tzu's Art of War in Simplified Chinese
$input = "孙子兵法";
$output = (new \Symfony\Component\String\UnicodeString($input))->ascii();
$expected = "sun zi bing fa";
if ($expected == $output) {
    echo "Well done!\n";
} else {
    echo "Oops: $output != $expected\n";
}

$ php84 test.php
...
$ apk --no-cache add icu-data-full
$ php84 test.php
...

Environment

- OS: alpine 3.22
- How docker service was installed: N/A

Docker creation

N/A

Container logs

N/A

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[mikespub]

Adding the alpine package icu-data-full fixes the issue (but increases the image size): https://wiki.alpinelinux.org/wiki/Release_Notes_for_Alpine_3.16.0#ICU_data_split

[mikespub]

Hi @aptalca is there any decision on whether the icu-data-full would be added to this base image, or if each dependent docker image with PHP should add it themselves?

[thespad]

Yeah it's about a 30Mb increase which isn't the end of the world (although it's proportionally a big increase)

cr.spad.uk/linuxserver/baseimage-alpine-nginx   3.22                   6ec95ff6b0ab   16 seconds ago   103MB
ghcr.io/linuxserver/baseimage-alpine-nginx      3.22                   7ce840b8a44c   13 hours ago     71.2MB

I don't have a sense of how many downstream images might be affected, it's not something people have reported previously but that doesn't mean it's not happening.

[mikespub]

Searching for icu-data-full I see that it was added in several images that depend on baseimage-alpine too, not just baseimage-alpine-nginx.

So it's probably better to let the images that actually need it include it in their Dockerfile. But you might add a notice somewhere for those of us who aren't too familiar with what (or is not) included in the alpine base images ;-)

[thespad]

It's required by some packages like qt5-qtbase so finds its way into images indirectly

[mikespub]

Thanks - I'll focus on adapting docker-cops directly then. If anyone else has problems with PHP iconv or intl not converting international strings correctly, they can check if they need icu-data-full too...