feature #393 Updated to Symfony 3.2 BETA1 (javiereguiluz)

This PR was squashed before being merged into the master branch (closes #393).

Discussion
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Updated to Symfony 3.2 BETA1

The beta1 of Symfony 3.2 has just been released, so let's upgrade the Symfony Demo to catch bugs and deprecations before the final release.

Commits
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1caf537 Updated to Symfony 3.2 BETA1

Author: javiereguiluz

composer.json

@@ -23,9 +23,9 @@
         "sensio/framework-extra-bundle"        : "^3.0",
         "symfony/monolog-bundle"               : "^2.8",
         "symfony/swiftmailer-bundle"           : "^2.3",
-        "symfony/symfony"                      : "^3.1",
+        "symfony/symfony"                      : "^3.2-beta1",
         "twig/extensions"                      : "^1.3",
-        "twig/twig"                            : "^1.25",
+        "twig/twig"                            : "^1.27",
         "white-october/pagerfanta-bundle"      : "^1.0"
     },
     "require-dev": {

composer.lock

@@ -99,15 +99,16 @@ private function getCallableReflector($callable)
 
     private function getTemplateSource(\Twig_Template $template)
     {
+        $templateSource = $template->getSourceContext();
+
         return [
-            // Twig templates are not always stored in files, and so there is no
-            // API to get the filename from a template name in a generic way.
-            // The logic used here works only for templates stored in app/Resources/views
-            // and referenced via the "filename.html.twig" notation, not via the "::filename.html.twig"
-            // one or stored in bundles. This is enough for the needs of the demo app.
-            'file_path' => $this->kernelRootDir.'/Resources/views/'.$template->getTemplateName(),
+            // Twig templates are not always stored in files (they can be stored
+            // in a database for example). However, for the needs of the Symfony
+            // Demo app, we consider that all templates are stored in files and
+            // that their file paths can be obtained through the source context.
+            'file_path' => $templateSource->getPath(),
             'starting_line' => 1,
-            'source_code' => $template->getSource(),
+            'source_code' => $templateSource->getCode(),
         ];
     }