Fix leaks with multiple calls to DatePeriod iterator current()

Destroy the old value first. We can't skip recreating the value because
the object may have been changed in between calls.

Closes phpGH-18624.

Author: ndossche

NEWS

@@ -2,6 +2,9 @@ PHP                                                                        NEWS
 |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 ?? ??? ????, PHP 8.3.23
 
+- Date:
+  . Fix leaks with multiple calls to DatePeriod iterator current(). (nielsdos)
+
 - Intl:
   . Fix memory leak in intl_datetime_decompose() on failure. (nielsdos)
 

ext/date/php_date.c

@@ -1607,6 +1607,7 @@ static zval *date_period_it_current_data(zend_object_iterator *iter)
 	php_date_obj   *newdateobj;
 
 	/* Create new object */
+	zval_ptr_dtor(&iterator->current);
 	php_date_instantiate(get_base_date_class(object->start_ce), &iterator->current);
 	newdateobj = Z_PHPDATE_P(&iterator->current);
 	newdateobj->time = timelib_time_ctor();

ext/date/tests/multiple_calls_date_period_iterator_current.phpt

@@ -0,0 +1,42 @@
+--TEST--
+Multiple calls to DatePeriod iterator current() leak objects
+--FILE--
+<?php
+$start = new DateTime('2018-12-31 00:00:00');
+$end   = new DateTime('2019-12-31 00:00:00');
+
+$interval = new DateInterval('P1M');
+$period = new DatePeriod($start, $interval, 1);
+
+$iter = $period->getIterator();
+var_dump($iter->current());
+var_dump($iter->current());
+$iter->current()->setTimestamp(0);
+var_dump($iter->current());
+
+?>
+--EXPECT--
+object(DateTime)#9 (3) {
+  ["date"]=>
+  string(26) "2018-12-31 00:00:00.000000"
+  ["timezone_type"]=>
+  int(3)
+  ["timezone"]=>
+  string(3) "UTC"
+}
+object(DateTime)#9 (3) {
+  ["date"]=>
+  string(26) "2018-12-31 00:00:00.000000"
+  ["timezone_type"]=>
+  int(3)
+  ["timezone"]=>
+  string(3) "UTC"
+}
+object(DateTime)#9 (3) {
+  ["date"]=>
+  string(26) "2018-12-31 00:00:00.000000"
+  ["timezone_type"]=>
+  int(3)
+  ["timezone"]=>
+  string(3) "UTC"
+}