diff --git a/core/lib/Drupal/Core/Entity/Sql/SqlContentEntityStorageSchema.php b/core/lib/Drupal/Core/Entity/Sql/SqlContentEntityStorageSchema.php
index cdb9ae43a6..694c171fde 100644
--- a/core/lib/Drupal/Core/Entity/Sql/SqlContentEntityStorageSchema.php
+++ b/core/lib/Drupal/Core/Entity/Sql/SqlContentEntityStorageSchema.php
@@ -1204,7 +1204,22 @@ protected function addTableDefaults(&$schema) {
    *   A partial schema array for the base table.
    */
   protected function processBaseTable(ContentEntityTypeInterface $entity_type, array &$schema) {
-    $this->processIdentifierSchema($schema, $entity_type->getKey('id'));
+    // Account for a missing ID key. In theory this should not be necessary, but
+    // we support this for backwards-compatibility. Entity types can be declared
+    // without an ID field (and, thus, also without an ID key) if they are not
+    // stored (for example if they use ContentEntityNullStorage as the storage
+    // handler). Contact messages are an example of this. We then support other
+    // modules adding an ID field, for example via
+    // hook_entity_base_field_info(). Such a module is responsible for adding
+    // ID key to the entity type in its hook_install() implementation. (See
+    // Contact Storage Test for an example of this.) The ID field, however, will
+    // already have been installed at this point by the module installer itself.
+    // And because the last installed entity type is used when building the
+    // entity schema during field installation the entity type will not (yet)
+    // have an ID key when the ID field is being installed.
+    if ($entity_type->hasKey('id')) {
+      $this->processIdentifierSchema($schema, $entity_type->getKey('id'));
+    }
   }
 
   /**
diff --git a/core/modules/contact/tests/modules/contact_storage_test/contact_storage_test.install b/core/modules/contact/tests/modules/contact_storage_test/contact_storage_test.install
index a165267b8a..c56d5b5669 100644
--- a/core/modules/contact/tests/modules/contact_storage_test/contact_storage_test.install
+++ b/core/modules/contact/tests/modules/contact_storage_test/contact_storage_test.install
@@ -6,24 +6,18 @@
  */
 
 /**
- * Implements hook_module_preinstall().
+ * Implements hook_install().
  */
-function contact_storage_test_module_preinstall($module) {
-  // This test module alters the definition of the 'contact_message' entity type
-  // so we need to inform the system about our changes before additional field
-  // storage definitions are added by the module installer.
-  // @see contact_storage_test_entity_type_alter()
-  // @see contact_storage_test_entity_base_field_info
-  if ($module === 'contact_storage_test') {
-    $definition_update_manager = \Drupal::entityDefinitionUpdateManager();
-    $entity_type = $definition_update_manager->getEntityType('contact_message');
+function contact_storage_test_install() {
+  $entity_manager = \Drupal::entityManager();
+  $entity_type = $entity_manager->getDefinition('contact_message');
 
-    $entity_type->setStorageClass('\Drupal\Core\Entity\Sql\SqlContentEntityStorage');
-    $keys = $entity_type->getKeys();
-    $keys['id'] = 'id';
-    $entity_type->set('entity_keys', $keys);
-    $entity_type->set('base_table', 'contact_message');
+  // Recreate the original entity type definition, in order to notify the
+  // manager of what changed. The change of storage backend will trigger
+  // schema installation.
+  // @see contact_storage_test_entity_type_alter()
+  $original = clone $entity_type;
+  $original->setStorageClass('Drupal\Core\Entity\ContentEntityNullStorage');
 
-    $definition_update_manager->updateEntityType($entity_type);
-  }
+  $entity_manager->onEntityTypeUpdate($entity_type, $original);
 }
diff --git a/core/modules/contact/tests/modules/contact_storage_test/contact_storage_test.module b/core/modules/contact/tests/modules/contact_storage_test/contact_storage_test.module
index fbcd362572..cef976c6ff 100644
--- a/core/modules/contact/tests/modules/contact_storage_test/contact_storage_test.module
+++ b/core/modules/contact/tests/modules/contact_storage_test/contact_storage_test.module
@@ -33,8 +33,8 @@ function contact_storage_test_entity_base_field_info(EntityTypeInterface $entity
  */
 function contact_storage_test_entity_type_alter(array &$entity_types) {
   /** @var $entity_types \Drupal\Core\Entity\EntityTypeInterface[] */
-  // Set the controller class for contact messages to an alternate
-  // implementation of the \Drupal\Core\Entity\EntityStorageInterface interface.
+  // Set the controller class for nodes to an alternate implementation of the
+  // Drupal\Core\Entity\EntityStorageInterface interface.
   $entity_types['contact_message']->setStorageClass('\Drupal\Core\Entity\Sql\SqlContentEntityStorage');
   $keys = $entity_types['contact_message']->getKeys();
   $keys['id'] = 'id';