Fixed yii\db\ActiveRecord::with() unable to use relation defined via attached behavior in case asArray is enabled

framework/CHANGELOG.md

@@ -8,6 +8,7 @@ Yii Framework 2 Change Log
 - Bug #14711: Fixed `yii\web\ErrorHandler` displaying exception message in non-debug mode (samdark)
 - Enh #13814: MySQL unique index names can now contain spaces (df2)
 - Bug #15300: Fixed "Cannot read property 'style' of undefined" error at the error screen (vitorarantes)
+- Bug #15540: Fixed `yii\db\ActiveRecord::with()` unable to use relation defined via attached behavior in case `asArray` is enabled (klimov-paul)
 - Enh #15426: Added abilitiy to create and drop database views (igravity, vladis84)
 - Enh #10186: Use native `hash_equals` in `yii\base\Security::compareString()` if available, throw exception if non-strings are compared (aotd1, samdark)
 - Bug #15122: Fixed `yii\db\Command::getRawSql()` to properly replace expressions (hiscaler, samdark)

framework/db/ActiveQueryTrait.php

@@ -162,7 +162,9 @@ trait ActiveQueryTrait
     {
         $primaryModel = reset($models);
         if (!$primaryModel instanceof ActiveRecordInterface) {
-            $primaryModel = new $this->modelClass();
+            /* @var $modelClass ActiveRecordInterface */
+            $modelClass = $this->modelClass;
+            $primaryModel = $modelClass::instance();
         }
         $relations = $this->normalizeRelations($primaryModel, $with);
         /* @var $relation ActiveQuery */

tests/framework/db/ActiveRecordTest.php

@@ -1600,5 +1600,13 @@ abstract class ActiveRecordTest extends DatabaseTestCase
         $this->assertInstanceOf(OrderItemWithConstructor::className(), $item);
 
         $this->assertEquals(1, $item->item_id);
+
+        // @see https://github.com/yiisoft/yii2/issues/15540
+        $orders = OrderWithConstructor::find()
+            ->with(['customer.profile', 'orderItems'])
+            ->orderBy('id')
+            ->asArray(true)
+            ->all();
+        $this->assertCount(3, $orders);
     }
 }