Issue #2883450 by mohit_aghera, Patrick Bauer, lauriii, corneboele, aarti...

Issue #2883450 by mohit_aghera, Patrick Bauer, lauriii, corneboele, aarti zikre, madhu_h, TBI, smustgrave, svdhout: Missing url prefix on language neutral content

core/modules/language/src/Plugin/LanguageNegotiation/LanguageNegotiationUrl.php

@@ -130,7 +130,10 @@ public function processOutbound($path, &$options = [], Request $request = NULL,
     }
     $languages = array_flip(array_keys($this->languageManager->getLanguages()));
     // Language can be passed as an option, or we go for current URL language.
-    if (!isset($options['language'])) {
+    if (!isset($options['language']) || ($options['language'] instanceof LanguageInterface && in_array($options['language']->getId(), [
+      LanguageInterface::LANGCODE_NOT_SPECIFIED,
+      LanguageInterface::LANGCODE_NOT_APPLICABLE,
+    ]))) {
       $language_url = $this->languageManager->getCurrentLanguage(LanguageInterface::TYPE_URL);
       $options['language'] = $language_url;
     }

core/modules/node/tests/src/Functional/NodeTranslationUITest.php

@@ -577,4 +577,26 @@ public function testDetailsTitleIsNotEscaped() {
     $this->assertSession()->responseContains($markup);
   }
 
+  /**
+   * Test that when content is language neutral, it uses interface language.
+   *
+   * When language neutral content is displayed on interface language, it should
+   * consider the interface language for creating the content link.
+   */
+  public function testUrlPrefixOnLanguageNeutralContent() {
+    $this->drupalLogin($this->administrator);
+    $neutral_langcodes = [
+      LanguageInterface::LANGCODE_NOT_APPLICABLE,
+      LanguageInterface::LANGCODE_NOT_SPECIFIED,
+    ];
+    foreach ($neutral_langcodes as $langcode) {
+      $article = $this->drupalCreateNode(['type' => 'article', 'langcode' => $langcode]);
+      $this->drupalGet("{$this->langcodes[1]}/admin/content");
+      $this->assertSession()->linkByHrefExists("{$this->langcodes[1]}/node/{$article->id()}");
+
+      $this->drupalGet("{$this->langcodes[2]}/admin/content");
+      $this->assertSession()->linkByHrefExists("{$this->langcodes[2]}/node/{$article->id()}");
+    }
+  }
+
 }