Fix GH-16317: SimpleXML does not allow __debugInfo() overrides to work

ext/simplexml/simplexml.c

@@ -1225,12 +1225,12 @@ static HashTable *sxe_get_properties(zend_object *object) /* {{{ */
 }
 /* }}} */
 
-static HashTable * sxe_get_debug_info(zend_object *object, int *is_temp) /* {{{ */
+/* This custom handler exists because the var_dump adds a pseudo "@attributes" key. */
+PHP_METHOD(SimpleXMLElement, __debugInfo)
 {
-	*is_temp = 1;
-	return sxe_get_prop_hash(object, 1);
+	ZEND_PARSE_PARAMETERS_NONE();
+	RETURN_ARR(sxe_get_prop_hash(Z_OBJ_P(ZEND_THIS), 1));
 }
-/* }}} */
 
 static int sxe_objects_compare(zval *object1, zval *object2) /* {{{ */
 {
@@ -2733,7 +2733,6 @@ PHP_MINIT_FUNCTION(simplexml)
 	sxe_object_handlers.compare = sxe_objects_compare;
 	sxe_object_handlers.cast_object = sxe_object_cast;
 	sxe_object_handlers.count_elements = sxe_count_elements;
-	sxe_object_handlers.get_debug_info = sxe_get_debug_info;
 	sxe_object_handlers.get_closure = NULL;
 	sxe_object_handlers.get_gc = sxe_get_gc;
 

ext/simplexml/simplexml.stub.php

@@ -51,6 +51,8 @@ public function getName(): string {}
 
     public function __toString(): string {}
 
+    public function __debugInfo(): ?array {}
+
     /** @tentative-return-type */
     public function count(): int {}
 

ext/simplexml/tests/gh16317.phpt

@@ -0,0 +1,22 @@
+--TEST--
+GH-16317 (SimpleXML does not allow __debugInfo() overrides to work)
+--FILE--
+<?php
+
+class MySXE extends SimpleXMLElement {
+    public function __debugInfo(): array {
+        echo "invoked\n";
+        return ['x' => 1];
+    }
+}
+
+$sxe = simplexml_load_string('<root><a/></root>', MySXE::class);
+var_dump($sxe);
+
+?>
+--EXPECT--
+invoked
+object(MySXE)#1 (1) {
+  ["x"]=>
+  int(1)
+}