Fix: Suppress HTML output from async translation updates during core update

[Copilot]

When updating WordPress core with non-English locales, Language_Pack_Upgrader::async_upgrade() outputs HTML markup intended for the admin interface, polluting CLI output with <p>, <div>, and <script> tags.

Changes

Added early-priority hook to remove the async translation upgrader before it executes:

// In Core_Command::update(), after requiring upgrade.php
add_action(
    'upgrader_process_complete',
    function () {
        remove_action( 'upgrader_process_complete', array( 'Language_Pack_Upgrader', 'async_upgrade' ), 20 );
    },
    1
);

This matches the existing pattern used in plugin/theme updates per @swissspidy's recommendation.

Testing

Added Behat test scenario "No HTML output from async translation updates during core update" that verifies:

• No <p> tags in output
• No <div> tags in output
• No <script> tags in output
• No </div> closing tags in output

Fixes #191

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Unexpected HTML output when updating WordPress</issue_title>
<issue_description>If I update WP using wp core update I get a lot of unexpected HTML output coming from WordPress itself:

$ wp core update
Updating to version 4.0 (pt_BR)...
Descompactando a atualização...
<p>Algumas traduções precisam de atualização. Descanse por mais alguns segundos, enquanto atualizamos elas também.</p>
<div class="update-messages lp-show-latest"><h4>Atualizando traduções de WordPress (pt_BR)&#8230;</h4><p>Fazendo download da tradução de <span class="code">(http://downloads.wordpress.org/translation/core/4.0/pt_BR.zip)</span>&#8230;</p>
<p>Descompactando a atualização&#8230;</p>
<p>Instalando a versão mais recente&#8230;</p>
<p>Tradução atualizada com sucesso.</p>
</div><script type="text/javascript">
                (function( wp ) {
                    if ( wp && wp.updates.decrementCount ) {
                        wp.updates.decrementCount( "translation" );
                    }
                })( window.wp );
            </script></div></div>Success: WordPress updated successfully.

This output is coming from the new WP code to automatically update translations when updating core.

It seems that WP_CLI\UpgraderSkin is not being used in this context because the static method Language_Pack_Upgrader::async_upgrade() instantiate Language_Pack_Upgrader class with a hard coded skin. I guess we will have to open a new ticket on core. I decided to open an issue here first in case anyone has another idea on how to fix this.
</issue_description>

Comments on the Issue (you are @copilot in this section)

@danielbachhuber > I guess we will have to open a new ticket on core.

Please link the ticket here when you open it.

@danielbachhuber @rodrigoprimo Can you provide a reproducible test case for this? I'm not sure whether it's still a bug, as I can't reproduce locally. @danielbachhuber @rodrigoprimo 👍 thanks @ernilambar I got similar output when I upgraded from 4.5.3 to 4.6. I ignored it thinking some language update issue. Hindi language was activated in my system. May be it appears in update in language other than default English. @ernilambar Steps to reproduce. - Install WP 4.5.3 - Install and activate `hi_IN` language - Update to 4.6. - After update:

Updating to version 4.6 (hi_IN)...
https://downloads.wordpress.org/release/hi_IN/wordpress-4.6.zip से अपडेट डाउनलोड कर रहे हैं...
अपडेट अनपैकिंग...
<p>अपने अनुवाद कुछ अपडेट की जरूरत है। हम के रूप में अच्छी तरह से उन्हें अद्यतन , जबकि कुछ और सेकंड के लिए तंग बैठो।</p>
<div class="update-messages lp-show-latest"><h2>Date Today Nepali (hi_IN)&#8230; के लिए अनुवाद का अद्यतन किया जा रहा है।</h2><p><span class="code">https://downloads.wordpress.org/translation/plugin/date-today-nepali/2.2/hi_IN.zip</span>&#8230; से अनुवाद डाउनलोड किया जा रहा</p>
<p>अपडेट अनपैकिंग&#8230;</p>
<p>नवीनतम संस्करण स्थापित(इन्सटॉल) कर रहे हैं&#8230;</p>
<p>अनुवाद सफलतापूर्वक अपडेट किया गया.</p>
</div><script type="text/javascript">
                    (function( wp ) {
                        if ( wp && wp.updates.decrementCount ) {
                            wp.updates.decrementCount( "translation" );
                        }
                    })( window.wp );
                </script>Cleaning up files...
No files found that need cleaned up.
Success: WordPress updated successfully.

@ernilambar Ahh, I had tested in existing WordPress setup. But now I checked again and there is no such output. I am not sure what happening actually 😁 @danielbachhuber @rodrigoprimo @ernilambar Is this a core bug, or a WP-CLI bug? @ernilambar I saw such output once. I tried but could not specifically reproduce it again. @danielbachhuber Ok. If someone can reproduce this with specific steps and identify where the bug is with WP-CLI, then we can get it fixed. @swissspidy Just happened to me today with `wp core update --version=nightly`.

A workaround could be to disable async translation updates using add_filter( 'async_update_translation', '__return_false' ); and instead encourage users to use wp language core update and the like for updates.</comment_new>
<comment_new>@schlessera
Yes, the behavior for core should be updated to match the one we currently have for plugins/themes.</comment_new>
<comment_new><author...

• Fixes Unexpected HTML output when updating WordPress #191

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