Issue #2972003 by alexpott: Verify that the file name matches the ID when installing configuration

core/lib/Drupal/Core/Config/ConfigInstaller.php

@@ -315,10 +315,11 @@ class ConfigInstaller implements ConfigInstallerInterface {
         $entity_storage = $this->configManager
           ->getEntityManager()
           ->getStorage($entity_type);
+
+        $id = $entity_storage->getIDFromConfigName($name, $entity_storage->getEntityType()->getConfigPrefix());
         // It is possible that secondary writes can occur during configuration
         // creation. Updates of such configuration are allowed.
         if ($this->getActiveStorages($collection)->exists($name)) {
-          $id = $entity_storage->getIDFromConfigName($name, $entity_storage->getEntityType()->getConfigPrefix());
           $entity = $entity_storage->load($id);
           $entity = $entity_storage->updateFromStorageRecord($entity, $new_config->get());
         }
@@ -327,6 +328,9 @@ class ConfigInstaller implements ConfigInstallerInterface {
         }
         if ($entity->isInstallable()) {
           $entity->trustData()->save();
+          if ($id !== $entity->id()) {
+            trigger_error(sprintf('The configuration name "%s" does not match the ID "%s"', $name, $entity->id()), E_USER_WARNING);
+          }
         }
       }
       else {

core/modules/config/tests/config_test_id_mismatch/config/install/config_test.dynamic.no_id_match.yml

@@ -0,0 +1,5 @@
+id: does_not_match
+label: Default
+weight: 0
+protected_property: Default
+langcode: en

core/modules/config/tests/config_test_id_mismatch/config_test_id_mismatch.info.yml

@@ -0,0 +1,7 @@
+name: 'Configuration test ID mismatch'
+type: module
+package: Testing
+version: VERSION
+core: 8.x
+dependencies:
+  - drupal:config_test

core/tests/Drupal/KernelTests/Core/Config/ConfigInstallTest.php

@@ -253,6 +253,14 @@ class ConfigInstallTest extends KernelTestBase {
     );
   }
 
+  /**
+   * Tests installing configuration where the filename and ID do not match.
+   */
+  public function testIdMisMatch() {
+    $this->setExpectedException(\PHPUnit_Framework_Error_Warning::class, 'The configuration name "config_test.dynamic.no_id_match" does not match the ID "does_not_match"');
+    $this->installModules(['config_test_id_mismatch']);
+  }
+
   /**
    * Installs a module.
    *