[php-src] Issue #7979: DatePeriod::getIterator()->valid() advances DatePeriod iterator

Issue: https://github.com/php/php-src/issues/7979 Comment Author: TysonAndre Specifically, it's caused by /* apply modification if it's not the first iteration */ in ext/date/php_date.c ```c // ext/date/php_date.c /* iterator handler table */ static const zend_object_iterator_funcs date_period_it_funcs = { date_period_it_dtor, date_period_it_has_more, // ... /* {{{ date_period_it_has_more */ static int date_period_it_has_more(zend_object_iterator *iter) { // ext/date/php_date.c date_period_it *iterator = (date_period_it *)iter; php_period_obj *object = Z_PHPPERIOD_P(&iterator->intern.data); timelib_time *it_time = object->current; /* apply modification if it's not the first iteration */ if (!object->include_start_date || iterator->current_index > 0) { it_time->have_relative = 1; it_time->relative = *object->interval; it_time->sse_uptodate = 0; timelib_update_ts(it_time, NULL); timelib_update_from_sse(it_time); } if (object->end) { return object->current->sse < object->end->sse ? SUCCESS : FAILURE; } else { return (iterator->current_index < object->recurrences) ? SUCCESS : FAILURE; } } /* }}} */ ```