Fixes #3772: Behaviors adding validation rules do not work as expected

framework/CHANGELOG.md

@@ -44,6 +44,7 @@ Yii Framework 2 Change Log
 - Bug #3751: Fixed postgreSQL schema data for enum values, do not add values if there are none (makroxyz)
 - Bug #3752: `QueryBuilder::batchInsert()` does not typecast input values (qiangxue)
 - Bug #3756: Fix number formatting error for `\yii\base\Formatter` by converting strings to float (kartik-v)
+- Bug #3772: Behaviors adding validation rules do not work as expected (qiangxue)
 - Bug #3817: `yii\rbac\PhpManager::getChildren()` returns null instead of expected empty array (qiangxue)
 - Bug #3843: Fixed Menu bug when using `template` with `encodeLabel` => false (creocoder, umneeq)
 - Bug #3863: Fixed incorrect js selector for `\yii\widgets\ActiveForm::errorSummaryCssClass` when it contains multiple classes (creocoder, umneeq)

framework/base/Model.php

@@ -310,28 +310,30 @@ class Model extends Component implements IteratorAggregate, ArrayAccess, Arrayab
      */
     public function validate($attributeNames = null, $clearErrors = true)
     {
+        if ($clearErrors) {
+            $this->clearErrors();
+        }
+
+        if (!$this->beforeValidate()) {
+            return false;
+        }
+
         $scenarios = $this->scenarios();
         $scenario = $this->getScenario();
         if (!isset($scenarios[$scenario])) {
             throw new InvalidParamException("Unknown scenario: $scenario");
         }
 
-        if ($clearErrors) {
-            $this->clearErrors();
-        }
         if ($attributeNames === null) {
             $attributeNames = $this->activeAttributes();
         }
-        if ($this->beforeValidate()) {
-            foreach ($this->getActiveValidators() as $validator) {
-                $validator->validateAttributes($this, $attributeNames);
-            }
-            $this->afterValidate();
 
-            return !$this->hasErrors();
+        foreach ($this->getActiveValidators() as $validator) {
+            $validator->validateAttributes($this, $attributeNames);
         }
+        $this->afterValidate();
 
-        return false;
+        return !$this->hasErrors();
     }
 
     /**