reverted back the previous changes, and fixed ChainedDependency.

framework/caching/ChainedDependency.php

@@ -22,11 +22,10 @@ namespace yii\caching;
 class ChainedDependency extends Dependency
 {
 	/**
-	 * @var array list of dependencies that this dependency is composed of.
-	 * Each array element should be a dependency object or a configuration array
-	 * that can be used to create a dependency object via [[\Yii::createObject()]].
+	 * @var Dependency[] list of dependencies that this dependency is composed of.
+	 * Each array element must be a dependency object.
 	 */
-	public $dependencies = array();
+	public $dependencies;
 	/**
 	 * @var boolean whether this dependency is depending on every dependency in [[dependencies]].
 	 * Defaults to true, meaning if any of the dependencies has changed, this dependency is considered changed.
@@ -37,9 +36,8 @@ class ChainedDependency extends Dependency
 
 	/**
 	 * Constructor.
-	 * @param array $dependencies list of dependencies that this dependency is composed of.
-	 * Each array element should be a dependency object or a configuration array
-	 * that can be used to create a dependency object via [[\Yii::createObject()]].
+	 * @param Dependency[] $dependencies list of dependencies that this dependency is composed of.
+	 * Each array element should be a dependency object.
 	 * @param array $config name-value pairs that will be used to initialize the object properties
 	 */
 	public function __construct($dependencies = array(), $config = array())
@@ -54,9 +52,6 @@ class ChainedDependency extends Dependency
 	public function evaluateDependency()
 	{
 		foreach ($this->dependencies as $dependency) {
-			if (!$dependency instanceof Dependency) {
-				$dependency = \Yii::createObject($dependency);
-			}
 			$dependency->evaluateDependency();
 		}
 	}
@@ -79,10 +74,7 @@ class ChainedDependency extends Dependency
 	 */
 	public function getHasChanged()
 	{
-		foreach ($this->dependencies as $i => $dependency) {
-			if (!$dependency instanceof Dependency) {
-				$this->dependencies[$i] = $dependency = \Yii::createObject($dependency);
-			}
+		foreach ($this->dependencies as $dependency) {
 			if ($this->dependOnAll && $dependency->getHasChanged()) {
 				return true;
 			} elseif (!$this->dependOnAll && !$dependency->getHasChanged()) {

framework/caching/DbDependency.php

@@ -28,23 +28,25 @@ class DbDependency extends Dependency
 	public $db = 'db';
 	/**
 	 * @var string the SQL query whose result is used to determine if the dependency has been changed.
-	 * Only the first row of the query result will be used. This property must be always set, otherwise
-	 * an exception would be raised.
+	 * Only the first row of the query result will be used.
 	 */
 	public $sql;
 	/**
 	 * @var array the parameters (name=>value) to be bound to the SQL statement specified by [[sql]].
 	 */
-	public $params = array();
+	public $params;
 
 	/**
-	 * Initializes the database dependency object.
+	 * Constructor.
+	 * @param string $sql the SQL query whose result is used to determine if the dependency has been changed.
+	 * @param array $params the parameters (name=>value) to be bound to the SQL statement specified by [[sql]].
+	 * @param array $config name-value pairs that will be used to initialize the object properties
 	 */
-	public function init()
+	public function __construct($sql, $params = array(), $config = array())
 	{
-		if ($this->sql === null) {
-			throw new InvalidConfigException('DbDependency::sql must be set.');
-		}
+		$this->sql = $sql;
+		$this->params = $params;
+		parent::__construct($config);
 	}
 
 	/**

framework/caching/ExpressionDependency.php

@@ -22,7 +22,18 @@ class ExpressionDependency extends Dependency
 	/**
 	 * @var string the PHP expression whose result is used to determine the dependency.
 	 */
-	public $expression = 'true';
+	public $expression;
+
+	/**
+	 * Constructor.
+	 * @param string $expression the PHP expression whose result is used to determine the dependency.
+	 * @param array $config name-value pairs that will be used to initialize the object properties
+	 */
+	public function __construct($expression = 'true', $config = array())
+	{
+		$this->expression = $expression;
+		parent::__construct($config);
+	}
 
 	/**
 	 * Generates the data needed to determine if dependency has been changed.

framework/caching/FileDependency.php

@@ -7,8 +7,6 @@
 
 namespace yii\caching;
 
-use yii\base\InvalidConfigException;
-
 /**
  * FileDependency represents a dependency based on a file's last modification time.
  *
@@ -22,19 +20,19 @@ class FileDependency extends Dependency
 {
 	/**
 	 * @var string the name of the file whose last modification time is used to
-	 * check if the dependency has been changed. This property must be always set,
-	 * otherwise an exception would be raised.
+	 * check if the dependency has been changed.
 	 */
 	public $fileName;
 
 	/**
-	 * Initializes the database dependency object.
+	 * Constructor.
+	 * @param string $fileName name of the file whose change is to be checked.
+	 * @param array $config name-value pairs that will be used to initialize the object properties
 	 */
-	public function init()
+	public function __construct($fileName = null, $config = array())
 	{
-		if ($this->file === null) {
-			throw new InvalidConfigException('FileDependency::fileName must be set.');
-		}
+		$this->fileName = $fileName;
+		parent::__construct($config);
 	}
 
 	/**