unify constructor initialization style throughout symfony

Author: Tobion

Helper/HelperSet.php

@@ -20,7 +20,7 @@
  */
 class HelperSet implements \IteratorAggregate
 {
-    private $helpers;
+    private $helpers = array();
     private $command;
 
     /**
@@ -30,7 +30,6 @@ class HelperSet implements \IteratorAggregate
      */
     public function __construct(array $helpers = array())
     {
-        $this->helpers = array();
         foreach ($helpers as $alias => $helper) {
             $this->set($helper, is_int($alias) ? null : $alias);
         }

Input/Input.php

@@ -24,9 +24,12 @@
  */
 abstract class Input implements InputInterface
 {
+    /**
+     * @var InputDefinition
+     */
     protected $definition;
-    protected $options;
-    protected $arguments;
+    protected $options = array();
+    protected $arguments = array();
     protected $interactive = true;
 
     /**
@@ -37,8 +40,6 @@ abstract class Input implements InputInterface
     public function __construct(InputDefinition $definition = null)
     {
         if (null === $definition) {
-            $this->arguments = array();
-            $this->options = array();
             $this->definition = new InputDefinition();
         } else {
             $this->bind($definition);

Shell.php

@@ -32,7 +32,7 @@ class Shell
     private $history;
     private $output;
     private $hasReadline;
-    private $processIsolation;
+    private $processIsolation = false;
 
     /**
      * Constructor.
@@ -48,7 +48,6 @@ public function __construct(Application $application)
         $this->application = $application;
         $this->history = getenv('HOME').'/.history_'.$application->getName();
         $this->output = new ConsoleOutput();
-        $this->processIsolation = false;
     }
 
     /**