From 6eb836b6f9b98c3c1b3078af6afd14c8ab3296e4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Haso=C5=88?= <martin.hason@gmail.com>
Date: Fri, 10 Jul 2020 11:08:50 +0200
Subject: [PATCH] [OptionsResolver] Fix force prepend normalizer

---
 .../Component/OptionsResolver/OptionsResolver.php     |  1 +
 .../OptionsResolver/Tests/OptionsResolverTest.php     | 11 +++++++++++
 2 files changed, 12 insertions(+)

diff --git a/src/Symfony/Component/OptionsResolver/OptionsResolver.php b/src/Symfony/Component/OptionsResolver/OptionsResolver.php
index 3fb3c06f92..d1aad4619b 100644
--- a/src/Symfony/Component/OptionsResolver/OptionsResolver.php
+++ b/src/Symfony/Component/OptionsResolver/OptionsResolver.php
@@ -532,6 +532,7 @@ class OptionsResolver implements Options
         }
 
         if ($forcePrepend) {
+            $this->normalizers[$option] = $this->normalizers[$option] ?? [];
             array_unshift($this->normalizers[$option], $normalizer);
         } else {
             $this->normalizers[$option][] = $normalizer;
diff --git a/src/Symfony/Component/OptionsResolver/Tests/OptionsResolverTest.php b/src/Symfony/Component/OptionsResolver/Tests/OptionsResolverTest.php
index 8e3c1d3331..1fa0e54645 100644
--- a/src/Symfony/Component/OptionsResolver/Tests/OptionsResolverTest.php
+++ b/src/Symfony/Component/OptionsResolver/Tests/OptionsResolverTest.php
@@ -1506,6 +1506,17 @@ class OptionsResolverTest extends TestCase
         $this->assertEquals(['foo' => '2nd-normalized-1st-normalized-bar'], $this->resolver->resolve());
     }
 
+    public function testForcePrependNormalizerForResolverWithoutPreviousNormalizers()
+    {
+        // defined by superclass
+        $this->resolver->setDefault('foo', 'bar');
+        $this->resolver->addNormalizer('foo', function (Options $options, $value) {
+            return '1st-normalized-'.$value;
+        }, true);
+
+        $this->assertEquals(['foo' => '1st-normalized-bar'], $this->resolver->resolve());
+    }
+
     public function testAddNormalizerFailsIfUnknownOption()
     {
         $this->expectException('Symfony\Component\OptionsResolver\Exception\UndefinedOptionsException');