commit 2ccdf89e26639effeab861e656c431b5ef120dd9
Author: Lee Rowlands <lee.rowlands@previousnext.com.au>
Date:   Wed Jul 8 09:52:03 2015 +1000

    p19

diff --git a/core/modules/block/block.install b/core/modules/block/block.install
index 60fbdfe..645f357 100644
--- a/core/modules/block/block.install
+++ b/core/modules/block/block.install
@@ -21,9 +21,11 @@ function block_update_8001() {
   ];
 
   $config_factory = \Drupal::configFactory();
+  $message = NULL;
   foreach ($config_factory->listAll('block.block.') as $block_config_name) {
     // We deal with config objects directly to avoid the config entity API.
     $block = $config_factory->getEditable($block_config_name);
+    $disable_block = FALSE;
     if ($visibility = $block->get('visibility')) {
       foreach ($visibility as &$condition) {
         foreach ($condition['context_mapping'] as $key => $context) {
@@ -32,19 +34,26 @@ function block_update_8001() {
             // and users can fix their block placements manually OR
             // alternatively contrib modules can run their own update functions
             // to update mappings that they provide.
-            drupal_set_message(\Drupal::translation()->translate('Encountered an unexpected context mapping key, one or more mappings could not be updated. Please manually review your block placements.'), 'error');
+            $message = \Drupal::translation()->translate('Encountered an unexpected context mapping key, one or more mappings could not be updated. Please manually review your block placements.');
+            $disable_block = TRUE;
             continue;
           }
           $new_context_id = explode('.', $context, 2);
           $condition['context_mapping'][$key] = '@' . $context_service_id_map[$key] . ':' . $new_context_id[1];
         }
       }
-
+      if ($disable_block) {
+        // This block will have an invalid context mapping service and must be
+        // disabled to avoid the 'You must provide the context IDs in the
+        // @{service_id}:{unqualified_context_id} format' exception.
+        $block->set('status', FALSE);
+      }
       $block->set('visibility', $visibility);
     }
 
     $block->save();
   }
+  return $message;
 }
 
 /**
diff --git a/core/modules/block/src/Tests/Update/BlockContextMappingUpdateTest.php b/core/modules/block/src/Tests/Update/BlockContextMappingUpdateTest.php
index 29c25aa..1a89537 100644
--- a/core/modules/block/src/Tests/Update/BlockContextMappingUpdateTest.php
+++ b/core/modules/block/src/Tests/Update/BlockContextMappingUpdateTest.php
@@ -35,6 +35,7 @@ protected function setUp() {
    */
   public function testUpdateHookN() {
     $this->runUpdates();
+    $this->assertText(t('Encountered an unexpected context mapping key, one or more mappings could not be updated. Please manually review your block placements.'));
 
     // Disable maintenance mode.
     \Drupal::state()->set('system.maintenance_mode', FALSE);
diff --git a/core/modules/system/tests/fixtures/update/drupal-8.block-context-manager-2354889.php b/core/modules/system/tests/fixtures/update/drupal-8.block-context-manager-2354889.php
index 34a810b..0ad77c5 100644
--- a/core/modules/system/tests/fixtures/update/drupal-8.block-context-manager-2354889.php
+++ b/core/modules/system/tests/fixtures/update/drupal-8.block-context-manager-2354889.php
@@ -99,6 +99,47 @@
     'status' => TRUE,
   ],
   'visibility' => [],
+],[
+  'uuid' => '4558907D-2918-48FE-B56F-8A007B5FBDD5',
+  'langcode' => 'en',
+  'status' => TRUE,
+  'dependencies' => [
+    'module' => [
+      'user',
+    ],
+    'theme' => [
+      'bartik',
+    ],
+  ],
+  'id' => 'thirdtestfor2354889',
+  'theme' => 'bartik',
+  'region' => 'sidebar_first',
+  'weight' => -6,
+  'provider' => NULL,
+  'plugin' => 'user_login_block',
+  'settings' => [
+    'id' => 'user_login_block',
+    'label' => 'User login',
+    'provider' => 'user',
+    'label_display' => 'visible',
+    'cache' => [
+      'max_age' => -1,
+    ],
+    'status' => TRUE,
+  ],
+  'visibility' => [
+    'node_type' => [
+      'id' => 'node_type',
+      'bundles' => [
+        'page' => 'page',
+      ],
+      'negate' => FALSE,
+      // Non-existent mapping that will be tested.
+      'context_mapping' => [
+        'baloney' => 'baloney.spam',
+      ],
+    ],
+  ],
 ]];
 
 foreach ($block_configs as $block_config) {