Issue #3134349 by sleitner, yookoala, sharma.amitt16, Akram Khan, sahil.goyal, swatichouhan012, s_leu, penyaskito, smustgrave, joachim, larowlan: \Drupal\language\LanguageNegotiator does not handle PluginNotFoundException and break the site completely

core/modules/language/src/LanguageNegotiator.php

@@ -2,8 +2,10 @@
 
 namespace Drupal\language;
 
+use Drupal\Component\Plugin\Exception\PluginNotFoundException;
 use Drupal\Component\Plugin\PluginManagerInterface;
 use Drupal\Core\Config\ConfigFactoryInterface;
+use Drupal\Core\Logger\LoggerChannelTrait;
 use Drupal\Core\Session\AccountInterface;
 use Drupal\Core\Site\Settings;
 use Drupal\language\Plugin\LanguageNegotiation\LanguageNegotiationUI;
@@ -13,6 +15,7 @@ use Symfony\Component\HttpFoundation\RequestStack;
  * Class responsible for performing language negotiation.
  */
 class LanguageNegotiator implements LanguageNegotiatorInterface {
+  use LoggerChannelTrait;
 
   /**
    * The language negotiation method plugin manager.
@@ -76,7 +79,7 @@ class LanguageNegotiator implements LanguageNegotiatorInterface {
    * @param \Drupal\language\ConfigurableLanguageManagerInterface $language_manager
    *   The language manager.
    * @param \Drupal\Component\Plugin\PluginManagerInterface $negotiator_manager
-   *   The language negotiation methods plugin manager
+   *   The language negotiation methods plugin manager.
    * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
    *   The configuration factory.
    * @param \Drupal\Core\Site\Settings $settings
@@ -130,7 +133,13 @@ class LanguageNegotiator implements LanguageNegotiatorInterface {
       // and return the first valid language found.
       foreach ($this->getEnabledNegotiators($type) as $method_id => $info) {
         if (!isset($this->negotiatedLanguages[$method_id])) {
-          $this->negotiatedLanguages[$method_id] = $this->negotiateLanguage($type, $method_id);
+          try {
+            $this->negotiatedLanguages[$method_id] = $this->negotiateLanguage($type, $method_id);
+          }
+          catch (PluginNotFoundException $e) {
+            // If a plugin is not found, log the error so user can handle it.
+            $this->getLogger('language')->error($e->getMessage());
+          }
         }
 
         // Since objects are references, we need to return a clone to prevent

core/modules/language/tests/src/Kernel/LanguageNegotiatorPluginTest.php

@@ -0,0 +1,54 @@
+<?php
+
+namespace Drupal\Tests\language\Kernel;
+
+use ColinODell\PsrTestLogger\TestLogger;
+use Drupal\Component\Plugin\Exception\PluginNotFoundException;
+use Drupal\Core\Language\LanguageInterface;
+use Drupal\Core\Logger\LoggerChannelFactory;
+use Drupal\KernelTests\KernelTestBase;
+
+/**
+ * Tests PluginNotFoundException.
+ *
+ * @group language
+ */
+class LanguageNegotiatorPluginTest extends KernelTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $modules = ['language', 'user'];
+
+  /**
+   * Tests for PluginNotFoundException.
+   */
+  public function testLanguageNegotiatorNoPlugin() {
+    $logger = new TestLogger();
+    $logger_factory = $this->createMock(LoggerChannelFactory::class);
+    $logger_factory->expects($this->once())
+      ->method('get')
+      ->with('language')
+      ->willReturn($logger);
+    $this->container->set('logger.factory', $logger_factory);
+    $this->installEntitySchema('user');
+
+    // Test unavailable plugin.
+    $config = $this->config('language.types');
+    $config->set('configurable', [LanguageInterface::TYPE_URL]);
+    $config->set('negotiation.language_url.enabled', [
+      self::CLASS => -3,
+    ]);
+    $config->save();
+    $languageNegotiator = $this->container->get('language_negotiator');
+    $languageNegotiator->setCurrentUser($this->prophesize('Drupal\Core\Session\AccountInterface')->reveal());
+    try {
+      $languageNegotiator->initializeType(LanguageInterface::TYPE_URL);
+    }
+    catch (PluginNotFoundException $exception) {
+      $this->fail('Plugin not found exception unhandled.');
+    }
+    $this->assertTrue($logger->hasErrorThatContains('The "Drupal\Tests\language\Kernel\LanguageNegotiatorPluginTest" plugin does not exist.'));
+  }
+
+}