From 763ea05db5c7ab8b5297aeabc5616d3eb9bd6fc7 Mon Sep 17 00:00:00 2001
From: Edvin Hultberg <hultberg@mittnett.net>
Date: Tue, 5 Oct 2021 19:39:51 +0200
Subject: [PATCH] [Serializer] Respect default context in
 DateTimeNormalizer::denormalize

fixes #29030
---
 .../Normalizer/DateTimeNormalizer.php         | 10 +++++++++
 .../Normalizer/DateTimeNormalizerTest.php     | 22 +++++++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/src/Symfony/Component/Serializer/Normalizer/DateTimeNormalizer.php b/src/Symfony/Component/Serializer/Normalizer/DateTimeNormalizer.php
index f48745031e8b7..5fab3d8a55d6d 100644
--- a/src/Symfony/Component/Serializer/Normalizer/DateTimeNormalizer.php
+++ b/src/Symfony/Component/Serializer/Normalizer/DateTimeNormalizer.php
@@ -113,6 +113,16 @@ public function denormalize($data, $type, $format = null, array $context = [])
             throw new NotNormalizableValueException(sprintf('Parsing datetime string "%s" using format "%s" resulted in %d errors: ', $data, $dateTimeFormat, $dateTimeErrors['error_count'])."\n".implode("\n", $this->formatDateTimeErrors($dateTimeErrors['errors'])));
         }
 
+        $defaultDateTimeFormat = $this->defaultContext[self::FORMAT_KEY] ?? null;
+
+        if (null !== $defaultDateTimeFormat) {
+            $object = \DateTime::class === $type ? \DateTime::createFromFormat($defaultDateTimeFormat, $data, $timezone) : \DateTimeImmutable::createFromFormat($defaultDateTimeFormat, $data, $timezone);
+
+            if (false !== $object) {
+                return $object;
+            }
+        }
+
         try {
             return \DateTime::class === $type ? new \DateTime($data, $timezone) : new \DateTimeImmutable($data, $timezone);
         } catch (\Exception $e) {
diff --git a/src/Symfony/Component/Serializer/Tests/Normalizer/DateTimeNormalizerTest.php b/src/Symfony/Component/Serializer/Tests/Normalizer/DateTimeNormalizerTest.php
index 51fc17d85afea..ca740a4d7e89e 100644
--- a/src/Symfony/Component/Serializer/Tests/Normalizer/DateTimeNormalizerTest.php
+++ b/src/Symfony/Component/Serializer/Tests/Normalizer/DateTimeNormalizerTest.php
@@ -305,6 +305,28 @@ public function testDenormalizeDateTimeStringWithSpacesUsingFormatPassedInContex
         $this->normalizer->denormalize('  2016.01.01  ', \DateTime::class, null, [DateTimeNormalizer::FORMAT_KEY => 'Y.m.d|']);
     }
 
+    public function testDenormalizeDateTimeStringWithDefaultContextFormat()
+    {
+        $format = 'd/m/Y';
+        $string = '01/10/2018';
+
+        $normalizer = new DateTimeNormalizer([DateTimeNormalizer::FORMAT_KEY => $format]);
+        $denormalizedDate = $normalizer->denormalize($string, \DateTimeInterface::class);
+
+        $this->assertSame('01/10/2018', $denormalizedDate->format($format));
+    }
+
+    public function testDenormalizeDateTimeStringWithDefaultContextAllowsErrorFormat()
+    {
+        $format = 'd/m/Y'; // the default format
+        $string = '2020-01-01'; // the value which is in the wrong format, but is accepted because of `new \DateTime` in DateTimeNormalizer::denormalize
+
+        $normalizer = new DateTimeNormalizer([DateTimeNormalizer::FORMAT_KEY => $format]);
+        $denormalizedDate = $normalizer->denormalize($string, \DateTimeInterface::class);
+
+        $this->assertSame('2020-01-01', $denormalizedDate->format('Y-m-d'));
+    }
+
     public function testDenormalizeFormatMismatchThrowsException()
     {
         $this->expectException(UnexpectedValueException::class);