Added ActiveRecordInterface::getOldPrimaryKey().

framework/yii/db/ActiveRecordInterface.php

@@ -70,6 +70,23 @@ interface ActiveRecordInterface
 	public function getPrimaryKey($asArray = false);
 
 	/**
+	 * Returns the old primary key value(s).
+	 * This refers to the primary key value that is populated into the record
+	 * after executing a find method (e.g. find(), findAll()).
+	 * The value remains unchanged even if the primary key attribute is manually assigned with a different value.
+	 * @param boolean $asArray whether to return the primary key value as an array. If true,
+	 * the return value will be an array with column name as key and column value as value.
+	 * If this is false (default), a scalar value will be returned for non-composite primary key.
+	 * @property mixed The old primary key value. An array (column name => column value) is
+	 * returned if the primary key is composite. A string is returned otherwise (null will be
+	 * returned if the key value is null).
+	 * @return mixed the old primary key value. An array (column name => column value) is returned if the primary key
+	 * is composite or `$asArray` is true. A string is returned otherwise (null will be returned if
+	 * the key value is null).
+	 */
+	public function getOldPrimaryKey($asArray = false);
+
+	/**
 	 * Creates an [[ActiveQueryInterface|ActiveQuery]] instance for query purpose.
 	 *
 	 * This method is usually ment to be used like this:

framework/yii/validators/ExistValidator.php

@@ -61,7 +61,7 @@ class ExistValidator extends Validator
 			return;
 		}
 
-		/** @var \yii\db\ActiveRecord $className */
+		/** @var \yii\db\ActiveRecordInterface $className */
 		$className = $this->className === null ? get_class($object) : $this->className;
 		$attributeName = $this->attributeName === null ? $attribute : $this->attributeName;
 		$query = $className::find();
@@ -85,7 +85,7 @@ class ExistValidator extends Validator
 		if ($this->attributeName === null) {
 			throw new InvalidConfigException('The "attributeName" property must be set.');
 		}
-		/** @var \yii\db\ActiveRecord $className */
+		/** @var \yii\db\ActiveRecordInterface $className */
 		$className = $this->className;
 		$query = $className::find();
 		$query->where([$this->attributeName => $value]);

framework/yii/validators/UniqueValidator.php

@@ -8,8 +8,6 @@
 namespace yii\validators;
 
 use Yii;
-use yii\base\InvalidConfigException;
-use yii\db\ActiveRecord;
 use yii\db\ActiveRecordInterface;
 
 /**
@@ -57,7 +55,7 @@ class UniqueValidator extends Validator
 			return;
 		}
 
-		/** @var \yii\db\ActiveRecord $className */
+		/** @var \yii\db\ActiveRecordInterface $className */
 		$className = $this->className === null ? get_class($object) : $this->className;
 		$attributeName = $this->attributeName === null ? $attribute : $this->attributeName;
 
@@ -69,9 +67,7 @@ class UniqueValidator extends Validator
 			$exists = $query->exists();
 		} else {
 			// if current $object is in the database already we can't use exists()
-			$query->limit(2);
+			$objects = $query->limit(2)->all();
-			$objects = $query->all();
-
 			$n = count($objects);
 			if ($n === 1) {
 				if (in_array($attributeName, $className::primaryKey())) {