feature #2635 Optimize the performance of the dot operator (fabpot)

This PR was squashed before being merged into the 2.x branch (closes #2635).

Discussion
----------

Optimize the performance of the dot operator

This is an alternative to #2359 and #2361, and closes #2326.

Basically, we don't need to call `hasExtension()` at runtime for the sandbox check when calling the dot operator as we know if it's enabled at compile time (the cache hash depends on enables extensions).

My benchmarks shows a *huge* performance improvement (**around 20%**) by doing so (especially when not using the sandbox, which is almost always the case).

Commits
-------

c917d352 fixed resetting options hash when overriding all extensions
89876d23 optimized the . operator performance

lib/Twig/Environment.php

@@ -681,6 +681,7 @@ class Twig_Environment
     public function setExtensions(array $extensions)
     {
         $this->extensionSet->setExtensions($extensions);
+        $this->updateOptionsHash();
     }
 
     /**

lib/Twig/Extension/Core.php

@@ -1432,7 +1432,7 @@ function twig_array_batch($items, $size, $fill = null)
  *
  * @internal
  */
-function twig_get_attribute(Twig_Environment $env, Twig_Source $source, $object, $item, array $arguments = array(), $type = Twig_Template::ANY_CALL, $isDefinedTest = false, $ignoreStrictCheck = false)
+function twig_get_attribute(Twig_Environment $env, Twig_Source $source, $object, $item, array $arguments = array(), $type = Twig_Template::ANY_CALL, $isDefinedTest = false, $ignoreStrictCheck = false, $sandboxed = false)
 {
     // array
     if (Twig_Template::METHOD_CALL !== $type) {
@@ -1514,7 +1514,7 @@ function twig_get_attribute(Twig_Environment $env, Twig_Source $source, $object,
                 return true;
             }
 
-            if ($env->hasExtension('Twig_Extension_Sandbox')) {
+            if ($sandboxed) {
                 $env->getExtension('Twig_Extension_Sandbox')->checkPropertyAllowed($object, $item);
             }
 
@@ -1591,7 +1591,7 @@ function twig_get_attribute(Twig_Environment $env, Twig_Source $source, $object,
         return true;
     }
 
-    if ($env->hasExtension('Twig_Extension_Sandbox')) {
+    if ($sandboxed) {
         $env->getExtension('Twig_Extension_Sandbox')->checkMethodAllowed($object, $method);
     }
 

lib/Twig/Node/Expression/GetAttr.php

@@ -23,9 +23,11 @@ class Twig_Node_Expression_GetAttr extends Twig_Node_Expression
 
     public function compile(Twig_Compiler $compiler)
     {
+        $env = $compiler->getEnvironment();
+
         // optimize array calls
         if (
-            (!$compiler->getEnvironment()->isStrictVariables() || $this->getAttribute('ignore_strict_check'))
+            (!$env->isStrictVariables() || $this->getAttribute('ignore_strict_check'))
             && !$this->getAttribute('is_defined_test')
             && Twig_Template::ARRAY_CALL === $this->getAttribute('type')
         ) {
@@ -58,7 +60,8 @@ class Twig_Node_Expression_GetAttr extends Twig_Node_Expression
         $compiler->raw(', ')->subcompile($this->getNode('attribute'));
 
         // only generate optional arguments when needed (to make generated code more readable)
-        $needFourth = $this->getAttribute('ignore_strict_check');
+        $needFifth = $env->hasExtension('Twig_Extension_Sandbox');
+        $needFourth = $needFifth || $this->getAttribute('ignore_strict_check');
         $needThird = $needFourth || $this->getAttribute('is_defined_test');
         $needSecond = $needThird || Twig_Template::ANY_CALL !== $this->getAttribute('type');
         $needFirst = $needSecond || $this->hasNode('arguments');
@@ -83,6 +86,10 @@ class Twig_Node_Expression_GetAttr extends Twig_Node_Expression
             $compiler->raw(', ')->repr($this->getAttribute('ignore_strict_check'));
         }
 
+        if ($needFifth) {
+            $compiler->raw(', ')->repr($env->hasExtension('Twig_Extension_Sandbox'));
+        }
+
         $compiler->raw(')');
     }
 }

test/Twig/Tests/TemplateTest.php

@@ -80,7 +80,7 @@ class Twig_Tests_TemplateTest extends \PHPUnit\Framework\TestCase
         $template = new Twig_TemplateTest($twig);
 
         try {
-            twig_get_attribute($twig, $template->getSourceContext(), $object, $item, array(), 'any');
+            twig_get_attribute($twig, $template->getSourceContext(), $object, $item, array(), 'any', false, false, true);
 
             if (!$allowed) {
                 $this->fail();