Issue #2779321 by nedjo, Akram Khan, smustgrave, catch, Meenakshi_j, pooja...

Issue #2779321 by nedjo, Akram Khan, smustgrave, catch, Meenakshi_j, pooja saraah, Berdir, alexpott: Submitting empty block layout form results in breakage for all block entities

(cherry picked from commit b5b29516)

core/modules/block/src/BlockListBuilder.php

@@ -373,7 +373,7 @@ public function getDefaultOperations(EntityInterface $entity) {
    */
   public function validateForm(array &$form, FormStateInterface $form_state) {
     if (empty($form_state->getValue('blocks'))) {
-      $form_state->setErrorByName('blocks', 'No blocks settings to update.');
+      $form_state->setErrorByName('blocks', $this->t('No blocks settings to update.'));
     }
 
   }
@@ -383,16 +383,13 @@ public function validateForm(array &$form, FormStateInterface $form_state) {
    */
   public function submitForm(array &$form, FormStateInterface $form_state) {
     $blocks = $form_state->getValue('blocks');
-    // Passing empty value to load Multiple would load all items from storage.
-    if (!empty($blocks)) {
-      $entities = $this->storage->loadMultiple(array_keys($blocks));
-      /** @var \Drupal\block\BlockInterface[] $entities */
-      foreach ($entities as $entity_id => $entity) {
-        $entity_values = $form_state->getValue(['blocks', $entity_id]);
-        $entity->setWeight($entity_values['weight']);
-        $entity->setRegion($entity_values['region']);
-        $entity->save();
-      }
+    $entities = $this->storage->loadMultiple(array_keys($blocks));
+    /** @var \Drupal\block\BlockInterface[] $entities */
+    foreach ($entities as $entity_id => $entity) {
+      $entity_values = $form_state->getValue(['blocks', $entity_id]);
+      $entity->setWeight($entity_values['weight']);
+      $entity->setRegion($entity_values['region']);
+      $entity->save();
     }
     $this->messenger->addStatus($this->t('The block settings have been updated.'));
   }

core/modules/block/tests/src/Functional/BlockUiTest.php

@@ -108,7 +108,8 @@ public function testBlockDemoUiPage() {
     $this->drupalGet('admin/structure/block/demo/stable9');
     $this->assertSession()->statusCodeEquals(404);
 
-    // Delete all blocks and verify block layout can be saved.
+    // Delete all blocks and verify saving the block layout results in a
+    // validation error.
     $block_storage = \Drupal::service('entity_type.manager')->getStorage('block');
     $blocks = $block_storage->loadMultiple();
     foreach ($blocks as $block) {
@@ -118,6 +119,7 @@ public function testBlockDemoUiPage() {
     $blocks_table = $this->xpath("//tr[@class='block-enabled']");
     $this->assertEmpty($blocks_table, 'The blocks table is now empty.');
     $this->submitForm([], 'Save blocks');
+    $this->assertSession()->pageTextContains('No blocks settings to update');
 
   }