feature #25780 [TwigBundle] Deprecating "false" in favor of "kernel.debug" as default value of "strict_variable" (yceruto)

This PR was merged into the 4.1-dev branch.

Discussion
----------

[TwigBundle] Deprecating "false" in favor of "kernel.debug" as default value of "strict_variable"

| Q             | A
| ------------- | ---
| Branch?       | master
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | yes
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

> http://symfony.com/doc/current/reference/configuration/twig.html#strict-variables
>**strict_variables**
> **type**: boolean **default**: `'%kernel.debug%'`

Nope, really it's `false` by default:
https://github.com/symfony/symfony/blob/1df45e43563a37633b50d4a36478090361a0b9de/src/Symfony/Bundle/TwigBundle/DependencyInjection/Configuration.php#L130

Fixing it in symfony/symfony-docs#9050, but yes `'%kernel.debug%'` is a better default value, the [TwigBundle recipe](https://github.com/symfony/recipes/blob/bf2148f9f1fe5af7e19c3145b6f7246c6cabb3a5/symfony/twig-bundle/3.3/config/packages/twig.yaml#L4:) affirms that:
```yaml
twig:
    # ...
    strict_variables: '%kernel.debug%'
```
So yeah, it definitely looks like it should be the default value, wdyt?

Commits
-------

922878e Deprecating "false" as default value of "strict_variable" under Twig configuration

Author: fabpot

UPGRADE-4.1.md

@@ -47,6 +47,11 @@ Translation
  * The `FileDumper::setBackup()` method is deprecated and will be removed in 5.0.
  * The `TranslationWriter::disableBackup()` method is deprecated and will be removed in 5.0.
 
+TwigBundle
+----------
+
+ * Deprecated relying on the default value (`false`) of the `twig.strict_variables` configuration option. You should use `%kernel.debug%` explicitly instead, which will be the new default in 5.0.
+
 Validator
 --------
 

UPGRADE-5.0.md

@@ -40,6 +40,11 @@ Translation
  * The `FileDumper::setBackup()` method has been removed.
  * The `TranslationWriter::disableBackup()` method has been removed.
 
+TwigBundle
+----------
+
+ * The default value (`false`) of the `twig.strict_variables` configuration option has been changed to `%kernel.debug%`.
+
 Validator
 --------
 

src/Symfony/Bundle/SecurityBundle/Tests/Functional/app/JsonLogin/config.yml

@@ -1,5 +1,5 @@
 imports:
-    - { resource: ./../config/framework.yml }
+    - { resource: ./../config/default.yml }
 
 security:
     encoders:

src/Symfony/Bundle/SecurityBundle/Tests/Functional/app/JsonLogin/custom_handlers.yml

@@ -1,5 +1,5 @@
 imports:
-    - { resource: ./../config/framework.yml }
+    - { resource: ./../config/default.yml }
 
 security:
     encoders:

src/Symfony/Bundle/TwigBundle/CHANGELOG.md

@@ -5,6 +5,7 @@ CHANGELOG
 -----
 
  * added priority to Twig extensions 
+ * deprecated relying on the default value (`false`) of the `twig.strict_variables` configuration option. The `%kernel.debug%` parameter will be the new default in 5.0
 
 4.0.0
 -----

src/Symfony/Bundle/TwigBundle/DependencyInjection/Configuration.php

@@ -127,7 +127,13 @@ private function addTwigOptions(ArrayNodeDefinition $rootNode)
                 ->scalarNode('cache')->defaultValue('%kernel.cache_dir%/twig')->end()
                 ->scalarNode('charset')->defaultValue('%kernel.charset%')->end()
                 ->booleanNode('debug')->defaultValue('%kernel.debug%')->end()
-                ->booleanNode('strict_variables')->end()
+                ->booleanNode('strict_variables')
+                    ->defaultValue(function () {
+                        @trigger_error('Relying on the default value ("false") of the "twig.strict_variables" configuration option is deprecated since Symfony 4.1. You should use "%kernel.debug%" explicitly instead, which will be the new default in 5.0.', E_USER_DEPRECATED);
+
+                        return false;
+                    })
+                ->end()
                 ->scalarNode('auto_reload')->end()
                 ->integerNode('optimizations')->min(-1)->end()
                 ->scalarNode('default_path')

src/Symfony/Bundle/TwigBundle/Tests/DependencyInjection/ConfigurationTest.php

@@ -20,6 +20,7 @@ class ConfigurationTest extends TestCase
     public function testDoNoDuplicateDefaultFormResources()
     {
         $input = array(
+            'strict_variables' => false, // to be removed in 5.0 relying on default
             'form_themes' => array('form_div_layout.html.twig'),
         );
 
@@ -28,4 +29,16 @@ public function testDoNoDuplicateDefaultFormResources()
 
         $this->assertEquals(array('form_div_layout.html.twig'), $config['form_themes']);
     }
+
+    /**
+     * @group legacy
+     * @expectedDeprecation Relying on the default value ("false") of the "twig.strict_variables" configuration option is deprecated since Symfony 4.1. You should use "%kernel.debug%" explicitly instead, which will be the new default in 5.0.
+     */
+    public function testGetStrictVariablesDefaultFalse()
+    {
+        $processor = new Processor();
+        $config = $processor->processConfiguration(new Configuration(), array(array()));
+
+        $this->assertFalse($config['strict_variables']);
+    }
 }

src/Symfony/Bundle/TwigBundle/Tests/DependencyInjection/Fixtures/php/customTemplateEscapingGuesser.php

@@ -3,4 +3,5 @@
 $container->loadFromExtension('twig', array(
     'autoescape_service' => 'my_project.some_bundle.template_escaping_guesser',
     'autoescape_service_method' => 'guess',
+    'strict_variables' => false, // to be removed in 5.0 relying on default
 ));

src/Symfony/Bundle/TwigBundle/Tests/DependencyInjection/Fixtures/php/empty.php

@@ -1,3 +1,5 @@
 <?php
 
-$container->loadFromExtension('twig', array());
+$container->loadFromExtension('twig', array(
+    'strict_variables' => false, // to be removed in 5.0 relying on default
+));

src/Symfony/Bundle/TwigBundle/Tests/DependencyInjection/Fixtures/php/extra.php

@@ -1,7 +1,8 @@
 <?php
 
 $container->loadFromExtension('twig', array(
-     'paths' => array(
-         'namespaced_path3' => 'namespace3',
-      ),
+    'paths' => array(
+        'namespaced_path3' => 'namespace3',
+    ),
+    'strict_variables' => false, // to be removed in 5.0 relying on default
 ));