bug #26895 [Config] Fixes the valid placeholder types for variable node (romain-pierre)

This PR was merged into the 4.1-dev branch.

Discussion
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[Config] Fixes the valid placeholder types for variable node

| Q             | A
| ------------- | ---
| Branch?       | master
| Bug fix?      | yes
| New feature?  | no <!-- don't forget to update src/**/CHANGELOG.md files -->
| BC breaks?    | no     <!-- see https://symfony.com/bc -->
| Deprecations? | no <!-- don't forget to update UPGRADE-*.md and src/**/CHANGELOG.md files -->
| Tests pass?   | we will see...    <!-- please add some, will be required by reviewers -->
| Fixed tickets | #26894
| License       | MIT

This is a proposition, still in discussion.
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Commits
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9fbdcdbeb9 Fixes the valid placeholder types for variable node

Author: fabpot

Tests/Compiler/ValidateEnvPlaceholdersPassTest.php

@@ -209,6 +209,19 @@ public function testEmptyEnvWhichCannotBeEmptyForScalarNode(): void
         $this->assertSame($expected, $container->resolveEnvPlaceholders($ext->getConfig()));
     }
 
+    public function testEnvWithVariableNode(): void
+    {
+        $container = new ContainerBuilder();
+        $container->registerExtension($ext = new EnvExtension());
+        $container->prependExtensionConfig('env_extension', $expected = array(
+            'variable_node' => '%env(SOME)%',
+        ));
+
+        $this->doProcess($container);
+
+        $this->assertSame($expected, $container->resolveEnvPlaceholders($ext->getConfig()));
+    }
+
     private function doProcess(ContainerBuilder $container): void
     {
         (new MergeExtensionConfigurationPass())->process($container);
@@ -247,6 +260,7 @@ public function getConfigTreeBuilder()
                 ->end()
                 ->arrayNode('simple_array_node')->end()
                 ->enumNode('enum_node')->values(array('a', 'b'))->end()
+                ->variableNode('variable_node')->end()
             ->end();
 
         return $treeBuilder;