Issue #1898804 by dawehner, tim.plunkett: Fixed Create a view block, place the block, delete the block, BOOM your site is dead.

core/modules/block/lib/Drupal/block/Plugin/views/display/Block.php

@@ -182,4 +182,16 @@ class Block extends DisplayPluginBase {
       return FALSE;
     }
 
+  /**
+   * Overrides \Drupal\views\Plugin\views\display\DisplayPluginBase::remove().
+   */
+  public function remove() {
+    parent::remove();
+
+    $plugin_id = 'views_block:' . $this->view->storage->id() . '-' . $this->display['id'];
+    foreach (entity_load_multiple_by_properties('block', array('plugin' => $plugin_id)) as $block) {
+      $block->delete();
+    }
+  }
+
 }

core/modules/block/lib/Drupal/block/Tests/Views/DisplayBlockTest.php

@@ -0,0 +1,140 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\block\Tests\Views\DisplayBlockTest.
+ */
+
+namespace Drupal\block\Tests\Views;
+
+use Drupal\block\Plugin\Core\Entity\Block;
+use Drupal\views\Tests\ViewTestBase;
+use Drupal\views\Tests\ViewTestData;
+
+/**
+ * Defines a test for block display.
+ *
+ * @see \Drupal\block\Plugin\views\display\Block
+ */
+class DisplayBlockTest extends ViewTestBase {
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  public static $modules = array('block_test_views', 'test_page_test');
+
+  /**
+   * Views used by this test.
+   *
+   * @var array
+   */
+  public static $testViews = array('test_view_block', 'test_view_block2');
+
+  public static function getInfo() {
+    return array(
+      'name' => ' Display: Block',
+      'description' => 'Tests the block display plugin.',
+      'group' => 'Views Modules',
+    );
+  }
+
+  protected function setUp() {
+    parent::setUp();
+
+    ViewTestData::importTestViews(get_class($this), array('block_test_views'));
+    $this->enableViewsTestModule();
+  }
+
+  /**
+   * Checks to see whether a block appears on the page.
+   *
+   * @param \Drupal\block\Plugin\Core\Entity\Block $block
+   *   The block entity to find on the page.
+   */
+  protected function assertBlockAppears(Block $block) {
+    $result = $this->findBlockInstance($block);
+    $this->assertTrue(!empty($result), format_string('Ensure the block @id appears on the page', array('@id' => $block->id())));
+  }
+
+  /**
+   * Checks to see whether a block does not appears on the page.
+   *
+   * @param \Drupal\block\Plugin\Core\Entity\Block $block
+   *   The block entity to find on the page.
+   */
+  protected function assertNoBlockAppears(Block $block) {
+    $result = $this->findBlockInstance($block);
+    $this->assertFalse(!empty($result), format_string('Ensure the block @id does not appear on the page', array('@id' => $block->id())));
+  }
+
+  /**
+   * Find a block instance on the page.
+   *
+   * @param \Drupal\block\Plugin\Core\Entity\Block $block
+   *   The block entity to find on the page.
+   *
+   * @return array
+   *   The result from the xpath query.
+   */
+  protected function findBlockInstance(Block $block) {
+    $config_id = explode('.', $block->id());
+    $machine_name = array_pop($config_id);
+    return $this->xpath('//div[@id = :id]', array(':id' => 'block-' . $machine_name));
+  }
+
+  /**
+   * Tests removing a block display.
+   */
+  protected function testDeleteBlockDisplay() {
+    // To test all combinations possible we first place create two instances
+    // of the block display of the first view.
+    $block_1 = $this->drupalPlaceBlock('views_block:test_view_block-block_1', array(), array('title' => 'test_view_block-block_1:1'));
+    $block_2 = $this->drupalPlaceBlock('views_block:test_view_block-block_1', array(), array('title' => 'test_view_block-block_1:2'));
+
+    // Then we add one instance of blocks for each of the two displays of the
+    // second view.
+    $block_3 = $this->drupalPlaceBlock('views_block:test_view_block2-block_1', array(), array('title' => 'test_view_block2-block_1'));
+    $block_4 = $this->drupalPlaceBlock('views_block:test_view_block2-block_2', array(), array('title' => 'test_view_block2-block_2'));
+
+    $this->drupalGet('test-page');
+    $this->assertBlockAppears($block_1);
+    $this->assertBlockAppears($block_2);
+    $this->assertBlockAppears($block_3);
+    $this->assertBlockAppears($block_4);
+
+    $block_storage_controller = $this->container->get('plugin.manager.entity')->getStorageController('block');
+
+    // Remove the block display, so both block entities from the first view
+    // should both dissapear.
+    $view = views_get_view('test_view_block');
+    $view->initDisplay();
+    $view->displayHandlers->remove('block_1');
+    $view->storage->save();
+
+    $this->assertFalse($block_storage_controller->load(array($block_1->id())), 'The block for this display was removed.');
+    $this->assertFalse($block_storage_controller->load(array($block_2->id())), 'The block for this display was removed.');
+    $this->assertTrue($block_storage_controller->load(array($block_3->id())), 'A block from another view was unaffected.');
+    $this->assertTrue($block_storage_controller->load(array($block_4->id())), 'A block from another view was unaffected.');
+    $this->drupalGet('test-page');
+    $this->assertNoBlockAppears($block_1);
+    $this->assertNoBlockAppears($block_2);
+    $this->assertBlockAppears($block_3);
+    $this->assertBlockAppears($block_4);
+
+    // Remove the first block display of the second view and ensure the block
+    // instance of the second block display still exists.
+    $view = views_get_view('test_view_block2');
+    $view->initDisplay();
+    $view->displayHandlers->remove('block_1');
+    $view->storage->save();
+
+    $this->assertFalse($block_storage_controller->load(array($block_3->id())), 'The block for this display was removed.');
+    $this->assertTrue($block_storage_controller->load(array($block_4->id())), 'A block from another display on the same view was unaffected.');
+    $this->drupalGet('test-page');
+    $this->assertNoBlockAppears($block_3);
+    $this->assertBlockAppears($block_4);
+  }
+
+}

core/modules/block/tests/block_test_views/block_test_views.info

@@ -0,0 +1,8 @@
+name = Block test views
+description = Provides a view and block to test block displays in views.
+package = Core
+version = VERSION
+hidden = TRUE
+core = 8.x
+dependencies[] = block
+dependencies[] = views

core/modules/block/tests/block_test_views/block_test_views.module

@@ -0,0 +1 @@
+<?php

core/modules/block/tests/block_test_views/test_views/views.view.test_view_block.yml

@@ -0,0 +1,47 @@
+base_field: id
+base_table: views_test_data
+core: 8.x
+description: ''
+disabled: '0'
+display:
+  default:
+    display_plugin: default
+    id: default
+    display_title: Master
+    position: ''
+    display_options:
+      access:
+        type: perm
+      cache:
+        type: none
+      query:
+        type: views_query
+      exposed_form:
+        type: basic
+      pager:
+        type: some
+        options:
+          items_per_page: '5'
+      style:
+        type: default
+      row:
+        type: fields
+      fields:
+        name:
+          id: name
+          table: views_test_data
+          field: name
+      title: test_view_block
+  block_1:
+    display_plugin: block
+    id: block_1
+    display_title: Block
+    position: ''
+    display_options:
+      field:
+        title:
+          link_to_node: '1'
+human_name: test_view_block
+module: views
+id: test_view_block
+tag: ''

core/modules/block/tests/block_test_views/test_views/views.view.test_view_block2.yml

@@ -0,0 +1,56 @@
+base_field: id
+base_table: views_test_data
+core: 8.x
+description: ''
+disabled: '0'
+display:
+  default:
+    display_plugin: default
+    id: default
+    display_title: Master
+    position: ''
+    display_options:
+      access:
+        type: perm
+      cache:
+        type: none
+      query:
+        type: views_query
+      exposed_form:
+        type: basic
+      pager:
+        type: some
+        options:
+          items_per_page: '5'
+      style:
+        type: default
+      row:
+        type: fields
+      fields:
+        name:
+          id: name
+          table: views_test_data
+          field: name
+      title: test_view_block2
+  block_1:
+    display_plugin: block
+    id: block_1
+    display_title: Block
+    position: ''
+    display_options:
+      field:
+        title:
+          link_to_node: '1'
+  block_2:
+    display_plugin: block
+    id: block_2
+    display_title: Block
+    position: ''
+    display_options:
+      field:
+        title:
+          link_to_node: '1'
+human_name: test_view_block2
+module: views
+id: test_view_block2
+tag: ''

core/modules/views/lib/Drupal/views/DisplayBag.php

@@ -92,4 +92,14 @@ class DisplayBag extends PluginBag {
     }
   }
 
+  /**
+   * Overrides \Drupal\Component\Plugin\PluginBag::remove().
+   */
+  public function remove($instance_id) {
+    $this->get($instance_id)->remove();
+
+    parent::remove($instance_id);
+  }
+
+
 }

core/modules/views/lib/Drupal/views/Plugin/views/display/DisplayPluginBase.php

@@ -2588,6 +2588,12 @@ abstract class DisplayPluginBase extends PluginBase {
     return $errors;
   }
 
+  /**
+   * Reacts on deleting a display.
+   */
+  public function remove() {
+  }
+
   /**
    * Check if the provided identifier is unique.
    *