From 7b6f767fbedb1162af805555a6081026243b48a2 Mon Sep 17 00:00:00 2001
From: Nicolas Grekas <nicolas.grekas@gmail.com>
Date: Wed, 8 Apr 2020 17:02:25 +0200
Subject: [PATCH] [DI] allow decorators to reference their decorated service
 using the special `.inner` id

---
 .../DependencyInjection/CHANGELOG.md          |  1 +
 .../Compiler/DecoratorServicePass.php         | 22 ++++++++++++++++++-
 .../Compiler/DecoratorServicePassTest.php     | 15 +++++++++++++
 3 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/src/Symfony/Component/DependencyInjection/CHANGELOG.md b/src/Symfony/Component/DependencyInjection/CHANGELOG.md
index 14c4104d89..104fdd56b7 100644
--- a/src/Symfony/Component/DependencyInjection/CHANGELOG.md
+++ b/src/Symfony/Component/DependencyInjection/CHANGELOG.md
@@ -4,6 +4,7 @@ CHANGELOG
 5.1.0
 -----
 
+ * allow decorators to reference their decorated service using the special `.inner` id
  * added support to autowire public typed properties in php 7.4
  * added support for defining method calls, a configurator, and property setters in `InlineServiceConfigurator`
  * added possibility to define abstract service arguments
diff --git a/src/Symfony/Component/DependencyInjection/Compiler/DecoratorServicePass.php b/src/Symfony/Component/DependencyInjection/Compiler/DecoratorServicePass.php
index 7e76064ce6..55f87b04b9 100644
--- a/src/Symfony/Component/DependencyInjection/Compiler/DecoratorServicePass.php
+++ b/src/Symfony/Component/DependencyInjection/Compiler/DecoratorServicePass.php
@@ -24,8 +24,15 @@ use Symfony\Component\DependencyInjection\Reference;
  * @author Fabien Potencier <fabien@symfony.com>
  * @author Diego Saint Esteben <diego@saintesteben.me>
  */
-class DecoratorServicePass implements CompilerPassInterface
+class DecoratorServicePass extends AbstractRecursivePass
 {
+    private $innerId = '.inner';
+
+    public function __construct(?string $innerId = '.inner')
+    {
+        $this->innerId = $innerId;
+    }
+
     public function process(ContainerBuilder $container)
     {
         $definitions = new \SplPriorityQueue();
@@ -49,6 +56,10 @@ class DecoratorServicePass implements CompilerPassInterface
             if (!$renamedId) {
                 $renamedId = $id.'.inner';
             }
+
+            $this->currentId = $renamedId;
+            $this->processValue($definition);
+
             $definition->innerServiceId = $renamedId;
             $definition->decorationOnInvalid = $invalidBehavior;
 
@@ -96,4 +107,13 @@ class DecoratorServicePass implements CompilerPassInterface
             $container->setAlias($inner, $id)->setPublic($public)->setPrivate($private);
         }
     }
+
+    protected function processValue($value, bool $isRoot = false)
+    {
+        if ($value instanceof Reference && $this->innerId === (string) $value) {
+            return new Reference($this->currentId, $value->getInvalidBehavior());
+        }
+
+        return parent::processValue($value, $isRoot);
+    }
 }
diff --git a/src/Symfony/Component/DependencyInjection/Tests/Compiler/DecoratorServicePassTest.php b/src/Symfony/Component/DependencyInjection/Tests/Compiler/DecoratorServicePassTest.php
index ed111d6d2c..bc9ff77b18 100644
--- a/src/Symfony/Component/DependencyInjection/Tests/Compiler/DecoratorServicePassTest.php
+++ b/src/Symfony/Component/DependencyInjection/Tests/Compiler/DecoratorServicePassTest.php
@@ -16,6 +16,7 @@ use Symfony\Component\DependencyInjection\Alias;
 use Symfony\Component\DependencyInjection\Compiler\DecoratorServicePass;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
 use Symfony\Component\DependencyInjection\ContainerInterface;
+use Symfony\Component\DependencyInjection\Reference;
 
 class DecoratorServicePassTest extends TestCase
 {
@@ -242,6 +243,20 @@ class DecoratorServicePassTest extends TestCase
         $this->assertEquals(['bar' => ['attr' => 'baz'], 'foobar' => ['attr' => 'bar']], $container->getDefinition('baz')->getTags());
     }
 
+    public function testGenericInnerReference()
+    {
+        $container = new ContainerBuilder();
+        $container->register('foo');
+
+        $container->register('bar')
+            ->setDecoratedService('foo')
+            ->setProperty('prop', new Reference('.inner'));
+
+        $this->process($container);
+
+        $this->assertEquals(['prop' => new Reference('bar.inner')], $container->getDefinition('bar')->getProperties());
+    }
+
     protected function process(ContainerBuilder $container)
     {
         $pass = new DecoratorServicePass();