Call to $this->languageManager->getLanguageSwitchLinks() breaks website language
>>> [!note] Migrated issue
<!-- Drupal.org comment -->
<!-- Migrated from issue #3569055. -->
Reported by: [anybody](https://www.drupal.org/user/291091)
>>>
<h3 id="summary-problem-motivation">Problem/Motivation</h3>
<p>In a client project we were wondering why parts of the page, e.g. header menu, tokens and some blocks were shown in the wrong language as anonymous user. Also one of the two language switchers used on the page shows the wrong language!</p>
<p>After debugging this for > 2H I found out that this one line causes all the trouble:</p>
<div class="codeblock">
<pre><span style="color: #000000"><span style="color: #0000BB"><?php<br>$languageSwitchLinksObject </span><span style="color: #007700">= </span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">languageManager</span><span style="color: #007700">-></span><span style="color: #0000BB">getLanguageSwitchLinks</span><span style="color: #007700">(</span><span style="color: #0000BB">$derivative_id</span><span style="color: #007700">, </span><span style="color: #0000BB">Url</span><span style="color: #007700">::</span><span style="color: #0000BB">fromRouteMatch</span><span style="color: #007700">(</span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">routeMatch</span><span style="color: #007700">));<br></span><span style="color: #0000BB">?></span></span></pre></div>
<p>in DropdownLanguage::build() function.</p>
<p>It seems to setConfigOverrideLanguage() which is then wrong for some parts of the page (which is totally weird!)</p>
<div class="codeblock">
<pre><span style="color: #000000"><span style="color: #0000BB"><?php<br> </span><span style="color: #FF8000">/**<br> * Sets the configuration override language.<br> *<br> * @param \Drupal\Core\Language\LanguageInterface $language<br> * The language to override configuration with.<br> *<br> * @return $this<br> */<br> </span><span style="color: #007700">public function </span><span style="color: #0000BB">setConfigOverrideLanguage</span><span style="color: #007700">(?</span><span style="color: #0000BB">LanguageInterface $language </span><span style="color: #007700">= </span><span style="color: #0000BB">NULL</span><span style="color: #007700">) {<br> </span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">configFactoryOverride</span><span style="color: #007700">-></span><span style="color: #0000BB">setLanguage</span><span style="color: #007700">(</span><span style="color: #0000BB">$language</span><span style="color: #007700">);<br> return </span><span style="color: #0000BB">$this</span><span style="color: #007700">;<br> }<br></span><span style="color: #0000BB">?></span></span></pre></div>
<p>in ConfigurableLanguageManager.</p>
<p>Commenting out this line, everyhing is fine. This only happens for anonymous users.<br>
It happens with and without bigpipe and it may have some combination with caching, but even disabling cache entirely does NOT work around it.</p>
<h4 id="summary-steps-reproduce">Steps to reproduce</h4>
<p>See above</p>
<h3 id="summary-proposed-resolution">Proposed resolution</h3>
<p>First we should look into <span class="drupalorg-gitlab-issue-link drupalorg-gitlab-link-wrapper"><a href="https://git.drupalcode.org/project/dropdown_language/-/work_items/3349246" class="drupalorg-gitlab-link">https://git.drupalcode.org/project/dropdown_language/-/work_items/3349246</a></span> and try to use as much of the core implementation as possible.</p>
<p>As I'm not sure if the Core Language Switcher is affected by the same bug, it's absolutely possible that this bug is in Core and the<br>
<code>$this->languageManager->getLanguageSwitchLinks()</code><br>
method itself, but I hope it's a bug in this module so it can be fixed easily.</p>
<h3 id="summary-remaining-tasks">Remaining tasks</h3>
<h3 id="summary-ui-changes">User interface changes</h3>
<p>None</p>
<h3 id="summary-api-changes">API changes</h3>
<p>None</p>
<h3 id="summary-data-model-changes">Data model changes</h3>
<p>None</p>
> Related issue: [Issue #3569172](https://www.drupal.org/node/3569172)
issue
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