diff --git a/core/includes/config.inc b/core/includes/config.inc
index fb2eca9..16586c6 100644
--- a/core/includes/config.inc
+++ b/core/includes/config.inc
@@ -194,7 +194,7 @@ function config_import_invoke_owner(array $config_changes, StorageInterface $sou
       // Check whether the module implements hook_config_import() and ask it to
       // handle the configuration change.
       $handled_by_module = FALSE;
-      if (module_hook($module, 'config_import')) {
+      if (module_hook($module, 'config_import_' . $op)) {
         $old_config = new Config($storage_dispatcher);
         $old_config
           ->setName($name)
@@ -217,7 +217,7 @@ function config_import_invoke_owner(array $config_changes, StorageInterface $sou
           $new_config->setData($data);
         }
 
-        $handled_by_module = module_invoke($module, 'config_import', $op, $name, $new_config, $old_config);
+        $handled_by_module = module_invoke($module, 'config_import_' . $op, $name, $new_config, $old_config);
       }
       if (!empty($handled_by_module)) {
         unset($config_changes[$op][$key]);
diff --git a/core/lib/Drupal/Core/Config/NullStorage.php b/core/lib/Drupal/Core/Config/NullStorage.php
index 54554c9..fede4f0 100644
--- a/core/lib/Drupal/Core/Config/NullStorage.php
+++ b/core/lib/Drupal/Core/Config/NullStorage.php
@@ -8,7 +8,18 @@
 namespace Drupal\Core\Config;
 
 /**
- * Defines the Null storage controller.
+ * Defines a stub storage controller.
+ *
+ * This storage is always empty; the controller reads and writes nothing.
+ *
+ * The stub implementation is needed for synchronizing configuration during
+ * installation of a module, in which case all configuration being shipped with
+ * the module is known to be new. Therefore, the module installation process is
+ * able to short-circuit the full diff against the active store; the diff would
+ * yield all currently available configuration as items to remove, since they do
+ * not exist in the module's default configuration directory.
+ *
+ * This also can be used for testing purposes.
  */
 class NullStorage implements StorageInterface {
   /**
diff --git a/core/modules/config/config.api.php b/core/modules/config/config.api.php
index 8cfa336..f0c3afa 100644
--- a/core/modules/config/config.api.php
+++ b/core/modules/config/config.api.php
@@ -13,19 +13,16 @@
  */
 
 /**
- * Synchronize configuration changes.
+ * Create configuration upon synchronizing configuration changes.
  *
  * This callback is invoked when configuration is synchronized between storages
  * and allows a module to take over the synchronization of configuration data.
  *
  * Modules should implement this callback if they manage configuration data
- * (such as image styles, node types, or fields), which needs to be
+ * (such as image styles, node types, or fields) which needs to be
  * prepared and passed through module API functions to properly handle a
  * configuration change.
  *
- * @param string $op
- *   The operation to perform for the configuration data; one of 'create',
- *   'delete', or 'change'.
  * @param string $name
  *   The name of the configuration object.
  * @param Drupal\Core\Config\Config $new_config
@@ -33,31 +30,78 @@
  * @param Drupal\Core\Config\Config $old_config
  *   A configuration object containing the old configuration data.
  */
-function MODULE_config_import($op, $name, $new_config, $old_config) {
+function MODULE_config_import_create($name, $new_config, $old_config) {
   // Only configurable thingies require custom handling. Any other module
   // settings can be synchronized directly.
   if (strpos($name, 'config_test.dynamic.') !== 0) {
     return FALSE;
   }
+  $config_test = new ConfigTest($new_config);
+  $config_test->save();
+  return TRUE;
+}
 
-  if ($op == 'delete') {
-    // @todo image_style_delete() supports the notion of a "replacement style"
-    //   to be used by other modules instead of the deleted style. Essential!
-    //   But that is impossible currently, since the config system only knows
-    //   about deleted and added changes. Introduce an 'old_ID' key within
-    //   config objects as a standard?
-    $config_test = new ConfigTest($old_config);
-    $config_test->delete();
-  }
-  if ($op == 'create') {
-    $config_test = new ConfigTest($new_config);
-    $config_test->save();
+/**
+ * Update configuration upon synchronizing configuration changes.
+ *
+ * This callback is invoked when configuration is synchronized between storages
+ * and allows a module to take over the synchronization of configuration data.
+ *
+ * Modules should implement this callback if they manage configuration data
+ * (such as image styles, node types, or fields) which needs to be
+ * prepared and passed through module API functions to properly handle a
+ * configuration change.
+ *
+ * @param string $name
+ *   The name of the configuration object.
+ * @param Drupal\Core\Config\Config $new_config
+ *   A configuration object containing the new configuration data.
+ * @param Drupal\Core\Config\Config $old_config
+ *   A configuration object containing the old configuration data.
+ */
+function MODULE_config_import_change($name, $new_config, $old_config) {
+  // Only configurable thingies require custom handling. Any other module
+  // settings can be synchronized directly.
+  if (strpos($name, 'config_test.dynamic.') !== 0) {
+    return FALSE;
   }
-  if ($op == 'change') {
-    $config_test = new ConfigTest($new_config);
-    $config_test->setOriginal($old_config);
-    $config_test->save();
+  $config_test = new ConfigTest($new_config);
+  $config_test->setOriginal($old_config);
+  $config_test->save();
+  return TRUE;
+}
+
+/**
+ * Delete configuration upon synchronizing configuration changes.
+ *
+ * This callback is invoked when configuration is synchronized between storages
+ * and allows a module to take over the synchronization of configuration data.
+ *
+ * Modules should implement this callback if they manage configuration data
+ * (such as image styles, node types, or fields) which needs to be
+ * prepared and passed through module API functions to properly handle a
+ * configuration change.
+ *
+ * @param string $name
+ *   The name of the configuration object.
+ * @param Drupal\Core\Config\Config $new_config
+ *   A configuration object containing the new configuration data.
+ * @param Drupal\Core\Config\Config $old_config
+ *   A configuration object containing the old configuration data.
+ */
+function MODULE_config_import_delete($name, $new_config, $old_config) {
+  // Only configurable thingies require custom handling. Any other module
+  // settings can be synchronized directly.
+  if (strpos($name, 'config_test.dynamic.') !== 0) {
+    return FALSE;
   }
+  // @todo image_style_delete() supports the notion of a "replacement style"
+  //   to be used by other modules instead of the deleted style. Essential!
+  //   But that is impossible currently, since the config system only knows
+  //   about deleted and added changes. Introduce an 'old_ID' key within
+  //   config objects as a standard?
+  $config_test = new ConfigTest($old_config);
+  $config_test->delete();
   return TRUE;
 }
 
diff --git a/core/modules/config/tests/config_test/config_test.module b/core/modules/config/tests/config_test/config_test.module
index e0a5ba5..3f3c520 100644
--- a/core/modules/config/tests/config_test/config_test.module
+++ b/core/modules/config/tests/config_test/config_test.module
@@ -5,9 +5,9 @@ use Drupal\config_test\ConfigTest;
 require_once dirname(__FILE__) . '/config_test.hooks.inc';
 
 /**
- * Implements hook_config_import().
+ * Implements MODULE_config_import_create().
  */
-function config_test_config_import($op, $name, $new_config, $old_config) {
+function config_test_config_import_create($name, $new_config, $old_config) {
   // Set a global value we can check in test code.
   $GLOBALS['hook_config_import'] = __FUNCTION__;
 
@@ -16,20 +16,43 @@ function config_test_config_import($op, $name, $new_config, $old_config) {
   if (strpos($name, 'config_test.dynamic.') !== 0) {
     return FALSE;
   }
+  $config_test = new ConfigTest($new_config);
+  $config_test->save();
+  return TRUE;
+}
 
-  if ($op == 'delete') {
-    $config_test = new ConfigTest($old_config);
-    $config_test->delete();
-  }
-  if ($op == 'create') {
-    $config_test = new ConfigTest($new_config);
-    $config_test->save();
+/**
+ * Implements MODULE_config_import_change().
+ */
+function config_test_config_import_change($name, $new_config, $old_config) {
+  // Set a global value we can check in test code.
+  $GLOBALS['hook_config_import'] = __FUNCTION__;
+
+  // Only configurable thingies require custom handling. Any other module
+  // settings can be synchronized directly.
+  if (strpos($name, 'config_test.dynamic.') !== 0) {
+    return FALSE;
   }
-  if ($op == 'change') {
-    $config_test = new ConfigTest($new_config);
-    $config_test->setOriginal($old_config);
-    $config_test->save();
+  $config_test = new ConfigTest($new_config);
+  $config_test->setOriginal($old_config);
+  $config_test->save();
+  return TRUE;
+}
+
+/**
+ * Implements MODULE_config_import_delete().
+ */
+function config_test_config_import_delete($name, $new_config, $old_config) {
+  // Set a global value we can check in test code.
+  $GLOBALS['hook_config_import'] = __FUNCTION__;
+
+  // Only configurable thingies require custom handling. Any other module
+  // settings can be synchronized directly.
+  if (strpos($name, 'config_test.dynamic.') !== 0) {
+    return FALSE;
   }
+  $config_test = new ConfigTest($old_config);
+  $config_test->delete();
   return TRUE;
 }
 
diff --git a/core/modules/image/image.module b/core/modules/image/image.module
index 363ddd6..397ac95 100644
--- a/core/modules/image/image.module
+++ b/core/modules/image/image.module
@@ -500,32 +500,47 @@ function image_path_flush($path) {
 }
 
 /**
- * Implements hook_config_import().
+ * Implements MODULE_config_import_create().
  */
-function image_config_import($op, $name, $new_config, $old_config) {
+function image_config_import_create($name, $new_config, $old_config) {
   // Only image styles require custom handling. Any other module settings can be
   // synchronized directly.
   if (strpos($name, 'image.style.') !== 0) {
     return FALSE;
   }
+  $style = $new_config->get();
+  return image_style_save($style);
+}
 
-  if ($op == 'delete') {
-    // @todo image_style_delete() supports the notion of a "replacement style"
-    //   to be used by other modules instead of the deleted style. Essential!
-    //   But that is impossible currently, since the config system only knows
-    //   about deleted and added changes. Introduce an 'old_ID' key within
-    //   config objects as a standard?
-    $style = $old_config->get();
-    return image_style_delete($style);
-  }
-  if ($op == 'create') {
-    $style = $new_config->get();
-    return image_style_save($style);
+/**
+ * Implements MODULE_config_import_change().
+ */
+function image_config_import_change($name, $new_config, $old_config) {
+  // Only image styles require custom handling. Any other module settings can be
+  // synchronized directly.
+  if (strpos($name, 'image.style.') !== 0) {
+    return FALSE;
   }
-  if ($op == 'change') {
-    $style = $new_config->get();
-    return image_style_save($style);
+  $style = $new_config->get();
+  return image_style_save($style);
+}
+
+/**
+ * Implements MODULE_config_import_delete().
+ */
+function image_config_import_delete($name, $new_config, $old_config) {
+  // Only image styles require custom handling. Any other module settings can be
+  // synchronized directly.
+  if (strpos($name, 'image.style.') !== 0) {
+    return FALSE;
   }
+  // @todo image_style_delete() supports the notion of a "replacement style"
+  //   to be used by other modules instead of the deleted style. Essential!
+  //   But that is impossible currently, since the config system only knows
+  //   about deleted and added changes. Introduce an 'old_ID' key within
+  //   config objects as a standard?
+  $style = $old_config->get();
+  return image_style_delete($style);
 }
 
 /**