Fix #18308: Fixed `\yii\base\Model::getErrorSummary()` reverse order

framework/CHANGELOG.md

@@ -6,6 +6,7 @@ Yii Framework 2 Change Log
 
 - Bug #16418: Fixed `yii\data\Pagination::getLinks()` to return links to the first and the last pages regardless of the current page (ptz-nerf, bizley)
 - Bug #18297: Replace usage of deprecated `ReflectionParameter::isArray()` method in PHP8 (baletskyi)
+- Bug #18308: Fixed `\yii\base\Model::getErrorSummary()` reverse order (DrDeath72)
 
 
 2.0.38 September 14, 2020

framework/base/Model.php

@@ -639,7 +639,7 @@ class Model extends Component implements StaticInstanceInterface, IteratorAggreg
         $lines = [];
         $errors = $showAllErrors ? $this->getErrors() : $this->getFirstErrors();
         foreach ($errors as $es) {
-            $lines = array_merge((array)$es, $lines);
+            $lines = array_merge($lines, (array)$es);
         }
         return $lines;
     }

tests/framework/base/ModelTest.php

@@ -322,8 +322,8 @@ class ModelTest extends TestCase
             'lastName' => ['Another one!'],
         ], $speaker->getErrors());
 
-        $this->assertEquals(['Another one!', 'Something is wrong!', 'Totally wrong!'], $speaker->getErrorSummary(true));
-        $this->assertEquals(['Another one!', 'Something is wrong!'], $speaker->getErrorSummary(false));
+        $this->assertEquals(['Something is wrong!', 'Totally wrong!', 'Another one!'], $speaker->getErrorSummary(true));
+        $this->assertEquals(['Something is wrong!', 'Another one!'], $speaker->getErrorSummary(false));
 
         $speaker->clearErrors('firstName');
         $this->assertEquals([