feature #1807 Inline original source code in compiled templates (nicolas-grekas)

This PR was submitted for the master branch but it was merged into the 1.x branch instead (closes #1807).

Discussion
----------

Inline original source code in compiled templates

For introspection purposes (e.g. instead of https://github.com/symfony/symfony/pull/15653) it is sometimes useful to be able to retrieve the original template source code.

I propose to inline it commented after the compiled class declaration.
This creates no memory nor cpu overhead while still allowing to get the source with very simple parsing logic.

Commits
-------

c9fb373 Inline original source code in compiled templates

lib/Twig/Environment.php

@@ -593,7 +593,13 @@ class Twig_Environment
     public function compileSource($source, $name = null)
     {
         try {
-            return $this->compile($this->parse($this->tokenize($source, $name)));
+            $compiled = $this->compile($this->parse($this->tokenize($source, $name)), $source);
+
+            if (isset($source[0])) {
+                $compiled .= '// '.str_replace(array("\r\n", "\r", "\n"), "\n// ", $source)."\n";
+            }
+
+            return $compiled;
         } catch (Twig_Error $e) {
             $e->setTemplateFile($name);
             throw $e;

test/Twig/Tests/EnvironmentTest.php

@@ -138,6 +138,14 @@ class Twig_Tests_EnvironmentTest extends PHPUnit_Framework_TestCase
         */
     }
 
+    public function testCompileSource()
+    {
+        $twig = new Twig_Environment($this->getMock('Twig_LoaderInterface'));
+
+        $expected = file_get_contents(__DIR__.'/Fixtures/environment-compile.php');
+        $this->assertSame($expected, $twig->compileSource("{{ foo }}\n{{ bar }}\n", 'index'));
+    }
+
     public function testExtensionsAreNotInitializedWhenRenderingACompiledTemplate()
     {
         $options = array('cache' => sys_get_temp_dir().'/twig', 'auto_reload' => false, 'debug' => false);

test/Twig/Tests/Fixtures/environment-compile.php

@@ -0,0 +1,45 @@
+<?php
+
+/* index */
+class __TwigTemplate_e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855 extends Twig_Template
+{
+    public function __construct(Twig_Environment $env)
+    {
+        parent::__construct($env);
+
+        $this->parent = false;
+
+        $this->blocks = array(
+        );
+    }
+
+    protected function doDisplay(array $context, array $blocks = array())
+    {
+        // line 1
+        echo twig_escape_filter($this->env, (isset($context["foo"]) ? $context["foo"] : null), "html", null, true);
+        echo "
+";
+        // line 2
+        echo twig_escape_filter($this->env, (isset($context["bar"]) ? $context["bar"] : null), "html", null, true);
+        echo "
+";
+    }
+
+    public function getTemplateName()
+    {
+        return "index";
+    }
+
+    public function isTraitable()
+    {
+        return false;
+    }
+
+    public function getDebugInfo()
+    {
+        return array (  23 => 2,  19 => 1,);
+    }
+}
+// {{ foo }}
+// {{ bar }}
+//