Update to Drupal 8.1.5. For more information, see https://www.drupal.org/project/drupal/releases/8.1.5

core/modules/block/migration_templates/d7_block.yml

@@ -19,6 +19,9 @@ process:
         - module
         - delta
       delimiter: _
+    -
+      plugin: machine_name
+      field: id
   plugin:
     -
       plugin: static_map

core/modules/block/src/Entity/Block.php

@@ -291,7 +291,6 @@ class Block extends ConfigEntityBase implements BlockInterface, EntityWithPlugin
    *   The condition plugin manager.
    */
   protected function conditionPluginManager() {
-    $this->conditionPluginManager;
     if (!isset($this->conditionPluginManager)) {
       $this->conditionPluginManager = \Drupal::service('plugin.manager.condition');
     }

core/modules/block/src/Plugin/migrate/source/Block.php

@@ -43,6 +43,13 @@ class Block extends DrupalSqlBase {
    */
   protected $blockRoleTable;
 
+  /**
+   * Table listing user roles.
+   *
+   * @var string
+   */
+  protected $userRoleTable;
+
   /**
    * {@inheritdoc}
    */
@@ -55,6 +62,9 @@ class Block extends DrupalSqlBase {
       $this->blockTable = 'blocks';
       $this->blockRoleTable = 'blocks_roles';
     }
+    // Drupal 6 & 7 both use the same name for the user roles table.
+    $this->userRoleTable = 'role';
+
     return $this->select($this->blockTable, 'b')->fields('b');
   }
 
@@ -106,11 +116,12 @@ class Block extends DrupalSqlBase {
     $module = $row->getSourceProperty('module');
     $delta = $row->getSourceProperty('delta');
 
-    $roles = $this->select($this->blockRoleTable, 'br')
+    $query = $this->select($this->blockRoleTable, 'br')
       ->fields('br', array('rid'))
       ->condition('module', $module)
-      ->condition('delta', $delta)
-      ->execute()
+      ->condition('delta', $delta);
+    $query->join($this->userRoleTable, 'ur', 'br.rid = ur.rid');
+    $roles = $query->execute()
       ->fetchCol();
     $row->setSourceProperty('roles', $roles);
 

core/modules/block/tests/src/Kernel/Migrate/d7/MigrateBlockTest.php

@@ -108,7 +108,7 @@ class MigrateBlockTest extends MigrateDrupal7TestBase {
     $this->assertEntity('bartik_system_main', 'system_main_block', [], '', 'content', 'bartik', 0, '', '0');
     $this->assertEntity('bartik_search_form', 'search_form_block', [], '', 'sidebar_first', 'bartik', -1, '', '0');
     $this->assertEntity('bartik_user_login', 'user_login_block', [], '', 'sidebar_first', 'bartik', 0, '', '0');
-    $this->assertEntity('bartik_system_powered-by', 'system_powered_by_block', [], '', 'footer', 'bartik', 10, '', '0');
+    $this->assertEntity('bartik_system_powered_by', 'system_powered_by_block', [], '', 'footer', 'bartik', 10, '', '0');
     $this->assertEntity('seven_system_main', 'system_main_block', [], '', 'content', 'seven', 0, '', '0');
     $this->assertEntity('seven_user_login', 'user_login_block', [], '', 'content', 'seven', 10, '', '0');
 

core/modules/block/tests/src/Unit/Plugin/migrate/source/BlockTest.php

@@ -25,6 +25,39 @@ class BlockTest extends MigrateSqlSourceTestCase {
    * Sample block instance query results from the source.
    */
   protected $expectedResults = array(
+    array(
+      'bid' => 1,
+      'module' => 'block',
+      'delta' => '1',
+      'theme' => 'garland',
+      'status' => 1,
+      'weight' => 0,
+      'region' => 'left',
+      'visibility' => 0,
+      'pages' => '',
+      'title' => 'Test Title 01',
+      'cache' => -1,
+      'roles' => [2]
+    ),
+    array(
+      'bid' => 2,
+      'module' => 'block',
+      'delta' => '2',
+      'theme' => 'garland',
+      'status' => 1,
+      'weight' => 5,
+      'region' => 'right',
+      'visibility' => 0,
+      'pages' => '<front>',
+      'title' => 'Test Title 02',
+      'cache' => -1,
+      'roles' => [2]
+    ),
+  );
+  /**
+   * Sample block table.
+   */
+  protected $expectedBlocks = array(
     array(
       'bid' => 1,
       'module' => 'block',
@@ -62,14 +95,35 @@ class BlockTest extends MigrateSqlSourceTestCase {
       'delta' => 1,
       'rid' => 2,
     ),
+    array(
+      'module' => 'block',
+      'delta' => 2,
+      'rid' => 2,
+    ),
+    array(
+      'module' => 'block',
+      'delta' => 2,
+      'rid' => 100,
+    ),
+  );
+
+  /**
+   * Sample role table.
+   */
+  protected $expectedRole = array(
+    array(
+      'rid' => 2,
+      'name' => 'authenticated user',
+    ),
   );
 
   /**
    * Prepopulate database contents.
    */
   protected function setUp() {
-    $this->databaseContents['blocks'] = $this->expectedResults;
+    $this->databaseContents['blocks'] = $this->expectedBlocks;
     $this->databaseContents['blocks_roles'] = $this->expectedBlocksRoles;
+    $this->databaseContents['role'] = $this->expectedRole;
     $this->databaseContents['system'] = array(
       array(
         'filename' => 'modules/system/system.module',