Post update system_post_update_add_langcode_to_all_translatable_config(&$sandbox = NULL) is clearing langcode from config system.site
// If this config contains any elements (at any level of nesting) which
// are translatable, but the config hasn't got a langcode, assign one. But
// if nothing in the config structure is translatable, the config shouldn't
// have a langcode at all.
if ($typed_config->hasTranslatableElements()) {
if ($config->get('langcode')) {
continue;
}
$config->set('langcode', $default_langcode);
}
else {
if (!array_key_exists('langcode', $config->get())) {
continue;
}
$config->clear('langcode');
}
$config->save();
But below code is trying to fetch langcode from system.site config which conflicting with above post update.
[warning] Undefined array key "langcode" DrupalKernel.php:1395
[warning] Undefined array key "langcode" DrupalKernel.php:1396
// Store the default language values on the container. This is so that the
// default language can be configured using the configuration factory. This
// avoids the circular dependencies that would created by
// \Drupal\language\LanguageServiceProvider::alter() and allows the default
// language to not be English in the installer.
$default_language_values = Language::$defaultValues;
if ($system = $this->getConfigStorage()->read('system.site')) {
if ($default_language_values['id'] != $system['langcode']) {
$default_language_values = ['id' => $system['langcode']];
}
}
Add a check if langcode config present or clean up the code in DrupalKernel.php checking langcode
Active
10.3 ✨
configuration system
Not every site has this configuration problem. It would be good to understand the real reason it occurs.
Yes, we need more information to investigate this.
Changes are made on on 11.x (our main development branch) first, and are then back ported as needed according to our policies.