Issue #1691394 by pwolanin, nod_, tim.plunkett: Fixed Drupal settings gets broken by AJAX requests.

core/lib/Drupal/Core/Ajax/AjaxResponse.php

@@ -133,6 +133,15 @@ protected function ajaxRender(Request $request) {
     $scripts = drupal_add_js();
     if (!empty($scripts['settings'])) {
       $settings = drupal_merge_js_settings($scripts['settings']['data']);
+      // During Ajax requests basic path-specific settings are excluded from
+      // new drupalSettings values. The original page where this request comes
+      // from already has the right values for the keys below. An Ajax request
+      // would update them with values for the Ajax request and incorrectly
+      // override the page's values.
+      // @see drupal_add_js
+      foreach (array('basePath', 'currentPath', 'scriptPath', 'pathPrefix') as $item) {
+        unset($settings[$item]);
+      }
       $this->addCommand(new SettingsCommand($settings, TRUE), TRUE);
     }
 

core/modules/system/lib/Drupal/system/Tests/Ajax/FrameworkTest.php

@@ -29,7 +29,7 @@ public static function getInfo() {
   /**
    * Ensures ajax_render() returns JavaScript settings from the page request.
    */
-  function testAJAXRender() {
+  public function testAJAXRender() {
     // Verify that settings command is generated when JavaScript settings are
     // set via drupal_add_js().
     $commands = $this->drupalGetAJAX('ajax-test/render');
@@ -40,7 +40,7 @@ function testAJAXRender() {
   /**
    * Tests AjaxResponse::prepare() AJAX commands ordering.
    */
-  function testOrder() {
+  public function testOrder() {
     $path = drupal_get_path('module', 'system');
     $expected_commands = array();
 
@@ -82,7 +82,7 @@ function testOrder() {
   /**
    * Tests behavior of ajax_render_error().
    */
-  function testAJAXRenderError() {
+  public function testAJAXRenderError() {
     // Verify custom error message.
     $edit = array(
       'message' => 'Custom error message.',
@@ -95,7 +95,7 @@ function testAJAXRenderError() {
   /**
    * Tests that new JavaScript and CSS files are lazy-loaded on an AJAX request.
    */
-  function testLazyLoad() {
+  public function testLazyLoad() {
     $expected = array(
       'setting_name' => 'ajax_forms_test_lazy_load_form_submit',
       'setting_value' => 'executed',
@@ -182,10 +182,22 @@ function testLazyLoad() {
     $this->assertCommand(array_slice($commands, 2, 1), array('data' => $expected_js_html), format_string('Page now has the %js file.', array('%js' => $expected['js'])));
   }
 
+  /**
+   * Tests that drupalSettings.currentPath is not updated on AJAX requests.
+   */
+  public function testCurrentPathChange() {
+    $commands = $this->drupalPostAJAX('ajax_forms_test_lazy_load_form', array('add_files' => FALSE), array('op' => t('Submit')));
+    foreach ($commands as $command) {
+      if ($command['command'] == 'settings') {
+        $this->assertFalse(isset($command['settings']['currentPath']), 'Value of drupalSettings.currentPath is not updated after an AJAX request.');
+      }
+    }
+  }
+
   /**
    * Tests that overridden CSS files are not added during lazy load.
    */
-  function testLazyLoadOverriddenCSS() {
+  public function testLazyLoadOverriddenCSS() {
     // The test theme overrides system.module.css without an implementation,
     // thereby removing it.
     theme_enable(array('test_theme'));

core/modules/system/tests/modules/ajax_forms_test/ajax_forms_test.module

@@ -534,6 +534,13 @@ function ajax_forms_test_validation_number_form_callback($form, $form_state) {
  * Form builder: Builds a form that triggers a simple AJAX callback.
  */
 function ajax_forms_test_lazy_load_form($form, &$form_state) {
+  // We attach a JavaScript setting, so that one of the generated AJAX commands
+  // will be a settings command. We can then check the settings command to
+  // ensure that the 'currentPath' setting is not part of the Ajax response.
+  $form['#attached']['js'][] = array(
+    'type' => 'setting',
+    'data' => array('test' => 'currentPathUpdate'),
+  );
   $form['add_files'] = array(
     '#type' => 'checkbox',
     '#default_value' => FALSE,