added ignore_invalid_variables setting to throw an exception when an invalid variable is used in a template

CHANGELOG

@@ -3,6 +3,7 @@
 Backward incompatibilities:
  * The short notation of the `block` tag changed.
 
+ * added ignore_invalid_variables setting to throw an exception when an invalid variable is used in a template (disabled automatically when debug is true)
  * added the lexer, parser, and compiler as arguments to the Twig_Environment constructor
  * changed the cache option to only accepts an explicit path to a cache directory or false
  * added a way to add token parsers, filters, and visitors without creating an extension

lib/Twig/Environment.php

@@ -29,6 +29,7 @@ class Twig_Environment
     protected $filters;
     protected $runtimeInitialized;
     protected $loadedTemplates;
+    protected $ignoreInvalidVars;
 
     /**
      * Constructor.
@@ -55,6 +56,8 @@ class Twig_Environment
      *    If you don't provide the auto_reload option, it will be
      *    determined automatically base on the debug value.
      *
+     *  * ignore_invalid_variables: Whether to ignore invalid variables in templates (default to the opposite value of debug).
+     *
      * @param Twig_LoaderInterface $loader  A Twig_LoaderInterface instance
      * @param array                $options An array of options
      */
@@ -74,6 +77,7 @@ class Twig_Environment
         $this->baseTemplateClass  = isset($options['base_template_class']) ? $options['base_template_class'] : 'Twig_Template';
         $this->autoReload         = isset($options['auto_reload']) ? (bool) $options['auto_reload'] : $this->debug;
         $this->extensions         = array('core' => new Twig_Extension_Core());
+        $this->ignoreInvalidVars  = isset($options['ignore_invalid_variables']) ? (bool) $options['ignore_invalid_variables'] : !$this->debug;
         $this->runtimeInitialized = false;
         if (isset($options['cache']) && $options['cache']) {
             $this->setCache($options['cache']);
@@ -115,6 +119,21 @@ class Twig_Environment
         $this->autoReload = (Boolean) $autoReload;
     }
 
+    public function enableignoreInvalidVars()
+    {
+        $this->ignoreInvalidVars = true;
+    }
+
+    public function disableignoreInvalidVars()
+    {
+        $this->ignoreInvalidVars = false;
+    }
+
+    public function ignoresInvalidVars()
+    {
+        return $this->ignoreInvalidVars;
+    }
+
     public function getCache()
     {
         return $this->cache;

lib/Twig/Node/Expression/Name.php

@@ -26,7 +26,7 @@ class Twig_Node_Expression_Name extends Twig_Node_Expression
 
     public function compile($compiler)
     {
-        $compiler->raw(sprintf('(isset($context[\'%s\']) ? $context[\'%s\'] : null)', $this->name, $this->name));
+        $compiler->raw(sprintf('$this->getContext($context, \'%s\')', $this->name, $this->name));
     }
 
     public function getName()

lib/Twig/Resource.php

@@ -29,6 +29,19 @@ abstract class Twig_Resource
         throw new Twig_RuntimeError(sprintf('The filter "%s" does not exist', $name));
     }
 
+    protected function getContext($context, $item)
+    {
+        if (isset($context[$item])) {
+            return $context[$item];
+        }
+
+        if ($this->env->ignoresInvalidVars()) {
+            return null;
+        }
+
+        throw new InvalidArgumentException(sprintf('Item "%s" from context does not exist.', $item));
+    }
+
     protected function getAttribute($object, $item, array $arguments = array(), $arrayOnly = false)
     {
         $item = (string) $item;
@@ -38,7 +51,11 @@ abstract class Twig_Resource
         }
 
         if ($arrayOnly || !is_object($object)) {
-            return null;
+            if ($this->env->ignoresInvalidVars()) {
+                return null;
+            }
+
+            throw new InvalidArgumentException(sprintf('Key "%s" for array "%s" does not exist.', $item, $object));
         }
 
         if (isset($object->$item)) {
@@ -67,7 +84,11 @@ abstract class Twig_Resource
         } elseif (isset($this->cache[$class]['__call'])) {
             $method = $item;
         } else {
-            return null;
+            if ($this->env->ignoresInvalidVars()) {
+                return null;
+            }
+
+            throw new InvalidArgumentException(sprintf('Method "%s" for object "%s" does not exist.', $item, get_class($object)));
         }
 
         if ($this->env->hasExtension('sandbox')) {