Cache DateTimeZone instances in DateHandler

Avoid creating new DateTimeZone objects on every deserialization call for the same timezone string. Instance-level caching.

Author: NikoGrano

src/Handler/DateHandler.php

@@ -37,6 +37,11 @@ final class DateHandler implements SubscribingHandlerInterface
      */
     private $xmlCData;
 
+    /**
+     * @var array<string, \DateTimeZone>
+     */
+    private $timezoneCache = [];
+
     /**
      * {@inheritdoc}
      */
@@ -250,7 +255,7 @@ public function deserializeDateIntervalFromJson(DeserializationVisitorInterface
      */
     private function parseDateTime($data, array $type, bool $immutable = false): \DateTimeInterface
     {
-        $timezone = !empty($type['params'][1]) ? new \DateTimeZone($type['params'][1]) : $this->defaultTimezone;
+        $timezone = !empty($type['params'][1]) ? $this->resolveTimezone($type['params'][1]) : $this->defaultTimezone;
         $formats = $this->getDeserializationFormats($type);
 
         $formatTried = [];
@@ -298,6 +303,15 @@ private function parseDateInterval(string $data): \DateInterval
         return $dateInterval;
     }
 
+    private function resolveTimezone(string $timezone): \DateTimeZone
+    {
+        if (!isset($this->timezoneCache[$timezone])) {
+            $this->timezoneCache[$timezone] = new \DateTimeZone($timezone);
+        }
+
+        return $this->timezoneCache[$timezone];
+    }
+
     /**
      * @param TypeArray $type
      */