added alias syntax support

fixes #13356
fixes #13359

framework/CHANGELOG.md

@@ -73,6 +73,7 @@ Yii Framework 2 Change Log
 - Enh #13254: Core validators no longer require `Yii::$app` to be set (sammousa)
 - Enh #13260: Added support for sorting by expression to `\yii\data\Sort` (LAV45, klimov-paul)
 - Enh #13278: `yii\caching\DbQueryDependency` created allowing specification of the cache dependency via `yii\db\QueryInterface` (klimov-paul)
+- Enh #13356: Support aliases in `MigrateController::$migrationNamespaces` to load non-namespaced migrations for BC with existing applications and extensions (schmunk42, cebe)
 - Enh #13360: Added Dockerized test setup for the framework tests (schmunk42)
 - Enh #13369: Added ability to render current `yii\widgets\LinkPager` page disabled (aquy)
 - Enh #13376: Data provider now automatically sets an ID so there is no need to set it manually in case multiple data providers are used with pagination (SamMousa)

framework/console/controllers/BaseMigrateController.php

@@ -13,6 +13,7 @@ use yii\console\Exception;
 use yii\console\Controller;
 use yii\helpers\Console;
 use yii\helpers\FileHelper;
+use yii\helpers\StringHelper;
 
 /**
  * BaseMigrateController is the base class for migrate controllers.
@@ -718,6 +719,9 @@ abstract class BaseMigrateController extends Controller
         if (strpos($class, '\\') === false) {
             $file = $this->migrationPath . DIRECTORY_SEPARATOR . $class . '.php';
             require_once($file);
+        } elseif (!class_exists($class, true)) {
+            // if the class with namespace does not exist, try to load it without namespace
+            $class = StringHelper::basename($class);
         }
 
         return new $class();