From 1c979c01729672b13c44637f2cc55484dfc1fb33 Mon Sep 17 00:00:00 2001
From: soyuka <soyuka@users.noreply.github.com>
Date: Mon, 27 Apr 2020 15:09:19 +0200
Subject: [PATCH] Fix serializer do not transform empty \Traversable to Array

---
 .../Component/Serializer/Serializer.php       |  6 +++++-
 .../Serializer/Tests/SerializerTest.php       | 21 +++++++++++++++++++
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/src/Symfony/Component/Serializer/Serializer.php b/src/Symfony/Component/Serializer/Serializer.php
index 94770484738f0..c166e1263040b 100644
--- a/src/Symfony/Component/Serializer/Serializer.php
+++ b/src/Symfony/Component/Serializer/Serializer.php
@@ -157,6 +157,10 @@ public function normalize($data, $format = null, array $context = [])
         }
 
         if (\is_array($data) || $data instanceof \Traversable) {
+            if ($data instanceof \Countable && 0 === $data->count()) {
+                return $data;
+            }
+
             $normalized = [];
             foreach ($data as $key => $val) {
                 $normalized[$key] = $this->normalize($val, $format, $context);
@@ -173,7 +177,7 @@ public function normalize($data, $format = null, array $context = [])
             throw new NotNormalizableValueException(sprintf('Could not normalize object of type "%s", no supporting normalizer found.', \get_class($data)));
         }
 
-        throw new NotNormalizableValueException(sprintf('An unexpected value could not be normalized: %s.', !\is_resource($data) ? var_export($data, true) : sprintf('%s resource', get_resource_type($data))));
+        throw new NotNormalizableValueException(sprintf('An unexpected value could not be normalized: "%s".', !\is_resource($data) ? var_export($data, true) : sprintf('"%s" resource', get_resource_type($data))));
     }
 
     /**
diff --git a/src/Symfony/Component/Serializer/Tests/SerializerTest.php b/src/Symfony/Component/Serializer/Tests/SerializerTest.php
index 9864c4e940360..fe8f8de929692 100644
--- a/src/Symfony/Component/Serializer/Tests/SerializerTest.php
+++ b/src/Symfony/Component/Serializer/Tests/SerializerTest.php
@@ -25,6 +25,7 @@
 use Symfony\Component\Serializer\Mapping\Factory\ClassMetadataFactory;
 use Symfony\Component\Serializer\Mapping\Factory\ClassMetadataFactoryInterface;
 use Symfony\Component\Serializer\Mapping\Loader\AnnotationLoader;
+use Symfony\Component\Serializer\Normalizer\AbstractObjectNormalizer;
 use Symfony\Component\Serializer\Normalizer\ArrayDenormalizer;
 use Symfony\Component\Serializer\Normalizer\CustomNormalizer;
 use Symfony\Component\Serializer\Normalizer\DenormalizerAwareInterface;
@@ -490,6 +491,26 @@ public function testNotNormalizableValueExceptionMessageForAResource()
         (new Serializer())->normalize(tmpfile());
     }
 
+    public function testNormalizePreserveEmptyArrayObject()
+    {
+        $serializer = new Serializer(
+          [
+              new PropertyNormalizer(),
+              new ObjectNormalizer(),
+              new ArrayDenormalizer(),
+          ],
+          [
+              'json' => new JsonEncoder(),
+          ]
+        );
+
+        $object = [];
+        $object['foo'] = new \ArrayObject();
+        $object['bar'] = new \ArrayObject(['notempty']);
+        $object['baz'] = new \ArrayObject(['nested' => new \ArrayObject()]);
+        $this->assertEquals('{"foo":{},"bar":["notempty"],"baz":{"nested":{}}}', $serializer->serialize($object, 'json', [AbstractObjectNormalizer::PRESERVE_EMPTY_OBJECTS => true]));
+    }
+
     private function serializerWithClassDiscriminator()
     {
         $classMetadataFactory = new ClassMetadataFactory(new AnnotationLoader(new AnnotationReader()));