Issue #2843892 by slashrsm, Berdir, dawehner: Query arguments are not persisted when using batch

core/includes/batch.inc

@@ -491,17 +491,13 @@ function _batch_finished() {
       $_SESSION['batch_form_state'] = $_batch['form_state'];
     }
     $callback = $_batch['redirect_callback'];
-    /** @var \Drupal\Core\Url $source_url */
-    $source_url = $_batch['source_url'];
+    $_batch['source_url']->mergeOptions(['query' => ['op' => 'finish', 'id' => $_batch['id']]]);
     if (is_callable($callback)) {
-      $callback($_batch['source_url'], array('query' => array('op' => 'finish', 'id' => $_batch['id'])));
+      $callback($_batch['source_url'], $_batch['source_url']->getOption('query'));
     }
     elseif ($callback === NULL) {
       // Default to RedirectResponse objects when nothing specified.
-      $url = $source_url
-        ->setAbsolute()
-        ->setOption('query', ['op' => 'finish', 'id' => $_batch['id']]);
-      return new RedirectResponse($url->toString());
+      return new RedirectResponse($_batch['source_url']->setAbsolute()->toString());
     }
   }
 }

core/includes/form.inc

@@ -782,6 +782,9 @@ function batch_set($batch_definition) {
  *   \Symfony\Component\HttpFoundation\RedirectResponse, which will be used
  *   automatically by the standard batch processing pipeline (and which takes
  *   precedence over this parameter).
+ *   User will be redirected to the page that started the batch if this argument
+ *   is omitted and no redirect response was returned by the 'finished'
+ *   callback. Any query arguments will be automatically persisted.
  * @param \Drupal\Core\Url $url
  *   (optional - should only be used for separate scripts like update.php)
  *   URL of the batch processing page.
@@ -801,7 +804,7 @@ function batch_process($redirect = NULL, Url $url = NULL, $redirect_callback = N
       'current_set' => 0,
       'progressive' => TRUE,
       'url' => isset($url) ? $url : Url::fromRoute('system.batch_page.html'),
-      'source_url' => Url::fromRouteMatch(\Drupal::routeMatch()),
+      'source_url' => Url::fromRouteMatch(\Drupal::routeMatch())->mergeOptions(['query' => \Drupal::request()->query->all()]),
       'batch_redirect' => $redirect,
       'theme' => \Drupal::theme()->getActiveTheme()->getName(),
       'redirect_callback' => $redirect_callback,

core/modules/system/src/Tests/Batch/ProcessingTest.php

@@ -107,6 +107,13 @@ function testBatchFormMultistep() {
     $this->assertEqual(batch_test_stack(), $this->_resultStack('batch_2'), 'Execution order was correct.');
     $this->assertText('Redirection successful.', 'Redirection after batch execution is correct.');
     $this->assertNoEscaped('<', 'No escaped markup is present.');
+
+    // Extra query arguments will trigger logic that will add them to the
+    // redirect URL. Make sure they are persisted.
+    $this->drupalGet('batch-test/multistep', ['query' => ['big_tree' => 'small_axe']]);
+    $this->drupalPostForm(NULL, array(), 'Submit');
+    $this->assertText('step 2', 'Form is displayed in step 2.');
+    $this->assertTrue(strpos($this->getUrl(), 'batch-test/multistep?big_tree=small_axe'), 'Query argument was persisted and another extra argument was added.');
   }
 
   /**