From 1868de8b1064b1fab4fd7c4a4b72a778ed3ca004 Mon Sep 17 00:00:00 2001
From: Scott Dawson <scott@loyaltycorp.com.au>
Date: Mon, 18 Nov 2019 13:12:17 +1100
Subject: [PATCH] [Validator] Validate timezone before passing to
 IntlDateFormatter

---
 .../Component/Validator/ConstraintValidator.php |  8 +++++++-
 .../Validator/Tests/ConstraintValidatorTest.php | 17 +++++++++++++++++
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/src/Symfony/Component/Validator/ConstraintValidator.php b/src/Symfony/Component/Validator/ConstraintValidator.php
index 93cca2ea74a5e..08811c9798b71 100644
--- a/src/Symfony/Component/Validator/ConstraintValidator.php
+++ b/src/Symfony/Component/Validator/ConstraintValidator.php
@@ -87,8 +87,14 @@ protected function formatValue($value, $format = 0)
     {
         if (($format & self::PRETTY_DATE) && $value instanceof \DateTimeInterface) {
             if (class_exists('IntlDateFormatter')) {
+                $timezone = $value->getTimezone();
+                // Timezone 'Z' is a valid ISO8601 indicator for UTC
+                $timezone = 'Z' === strtoupper($timezone->getName()) ? new \DateTimeZone('UTC') : $timezone;
+                // Only use timezone if it's valid, otherwise fall back to system default
+                $timezone = \in_array($timezone->getName(), \DateTimeZone::listIdentifiers(), true) ? $timezone : null;
+
                 $locale = \Locale::getDefault();
-                $formatter = new \IntlDateFormatter($locale, \IntlDateFormatter::MEDIUM, \IntlDateFormatter::SHORT, $value->getTimezone());
+                $formatter = new \IntlDateFormatter($locale, \IntlDateFormatter::MEDIUM, \IntlDateFormatter::SHORT, $timezone);
 
                 // neither the native nor the stub IntlDateFormatter support
                 // DateTimeImmutable as of yet
diff --git a/src/Symfony/Component/Validator/Tests/ConstraintValidatorTest.php b/src/Symfony/Component/Validator/Tests/ConstraintValidatorTest.php
index 96af6f13eb4e7..8584e0dc91511 100644
--- a/src/Symfony/Component/Validator/Tests/ConstraintValidatorTest.php
+++ b/src/Symfony/Component/Validator/Tests/ConstraintValidatorTest.php
@@ -25,6 +25,22 @@ public function testFormatValue($expected, $value, $format = 0)
         $this->assertSame($expected, (new TestFormatValueConstraintValidator())->formatValueProxy($value, $format));
     }
 
+    public function testInvalidTimezoneFallback()
+    {
+        if (!class_exists(\IntlDateFormatter::class)) {
+            $this->markTestSkipped('Test is only valid if IntlDateFormatter is present.');
+        }
+
+        $dateTime = new \DateTimeImmutable('1970-01-01T00:00:00X');
+
+        $locale = \Locale::getDefault();
+        $formatter = new \IntlDateFormatter($locale, \IntlDateFormatter::MEDIUM, \IntlDateFormatter::SHORT);
+        $expected = $formatter->format($dateTime);
+
+        $this->assertSame('X', $dateTime->getTimezone()->getName());
+        $this->assertSame($expected, (new TestFormatValueConstraintValidator())->formatValueProxy($dateTime, ConstraintValidator::PRETTY_DATE));
+    }
+
     public function formatValueProvider()
     {
         $data = [
@@ -38,6 +54,7 @@ public function formatValueProvider()
             ['ccc', $toString, ConstraintValidator::OBJECT_TO_STRING],
             ['object', $dateTime = (new \DateTimeImmutable('@0'))->setTimezone(new \DateTimeZone('UTC'))],
             [class_exists(\IntlDateFormatter::class) ? 'Jan 1, 1970, 12:00 AM' : '1970-01-01 00:00:00', $dateTime, ConstraintValidator::PRETTY_DATE],
+            [class_exists(\IntlDateFormatter::class) ? 'Jan 1, 1970, 12:00 AM' : '1970-01-01 00:00:00', (new \DateTimeImmutable('@0'))->setTimezone(new \DateTimeZone('Z')), ConstraintValidator::PRETTY_DATE],
         ];
 
         return $data;