Merge branch 'PHP-8.4'

* PHP-8.4:
  Fix phpGH-16149: Null pointer dereference in DOMElement->getAttributeNames()

Author: ndossche

ext/dom/element.c

@@ -361,7 +361,11 @@ PHP_METHOD(DOMElement, getAttributeNames)
 	if (!php_dom_follow_spec_intern(intern)) {
 		for (xmlNsPtr nsptr = nodep->nsDef; nsptr; nsptr = nsptr->next) {
 			const char *prefix = (const char *) nsptr->prefix;
-			ZVAL_NEW_STR(&tmp, dom_node_concatenated_name_helper(strlen(prefix), prefix, strlen("xmlns"), (const char *) "xmlns"));
+			if (prefix == NULL) {
+				ZVAL_STRING(&tmp, "xmlns");
+			} else {
+				ZVAL_NEW_STR(&tmp, dom_node_concatenated_name_helper(strlen(prefix), prefix, strlen("xmlns"), (const char *) "xmlns"));
+			}
 			zend_hash_next_index_insert(ht, &tmp);
 		}
 	}

ext/dom/tests/gh16149.phpt

@@ -0,0 +1,14 @@
+--TEST--
+GH-16149 (Null pointer dereference in DOMElement->getAttributeNames())
+--EXTENSIONS--
+dom
+--FILE--
+<?php
+$element = new DOMElement("b", null, "a");
+var_dump($element->getAttributeNames());
+?>
+--EXPECT--
+array(1) {
+  [0]=>
+  string(5) "xmlns"
+}