Fix BC break when using RFC3339 constants with Zulu timezone

Author: alganet

library/Helpers/CanValidateDateTime.php

@@ -16,6 +16,9 @@
 use function date_default_timezone_get;
 use function date_parse_from_format;
 use function preg_match;
+use function strlen;
+use function strrpos;
+use function substr;
 
 /**
  * Helper to handle date/time.
@@ -43,6 +46,10 @@ private function isDateTime(string $format, string $value): bool
         }
 
         if ($this->isDateFormat($format)) {
+            if (($format === DateTime::RFC3339_EXTENDED || $format === DateTime::RFC3339) && strrpos($value, 'Z') === strlen($value) - 1) {
+                $value = substr($value, 0, -1) . '+00:00';
+            }
+
             $formattedDate = DateTime::createFromFormat(
                 '!' . $format,
                 $value,

tests/unit/Helpers/CanValidateDateTimeTest.php

@@ -9,6 +9,7 @@
 
 namespace Respect\Validation\Helpers;
 
+use DateTime;
 use Respect\Validation\Test\TestCase;
 
 /**
@@ -57,6 +58,8 @@ public static function providerForValidDateTime(): array
             ['Y-m-d\TH:i:sP', '2018-01-30T19:04:35+00:00'],
             ['r', 'Tue, 30 Jan 2018 19:06:01 +0000'],
             ['D, d M Y H:i:s O', 'Tue, 30 Jan 2018 19:06:01 +0000'],
+            [DateTime::RFC3339_EXTENDED, '2014-04-12T23:20:50.052Z'],
+            [DateTime::RFC3339, '2005-08-15T15:52:01Z'],
         ];
     }