Fix SimpleXML invalidations

Test was Co-authored-by: tstarling

Author: nielsdos

ext/dom/tests/DOMDocument_getElementsByTagName_liveness_simplexml.phpt

@@ -0,0 +1,28 @@
+--TEST--
+DOMDocument::getElementsByTagName() liveness with simplexml_import_dom
+--EXTENSIONS--
+dom
+--FILE--
+<?php
+
+$doc = new DOMDocument;
+$doc->loadXML( '<root><e i="1"/><e i="2"/><e i="3"/><e i="4"/><e i="5"/><e i="6"/><e i="7"/><e i="8"/><e i="9"/><e i="10"/></root>' );
+$list = $doc->getElementsByTagName('e');
+print $list->item(5)->getAttribute('i')."\n";
+echo "before import\n";
+$s = simplexml_import_dom($doc->documentElement);
+echo "after import\n";
+
+unset($s->e[5]);
+print $list->item(5)->getAttribute('i')."\n";
+
+unset($s->e[5]);
+print $list->item(5)->getAttribute('i')."\n";
+
+?>
+--EXPECT--
+6
+before import
+after import
+7
+8

ext/simplexml/simplexml.c

@@ -43,6 +43,16 @@ PHP_SXE_API zend_class_entry *sxe_get_element_class_entry(void) /* {{{ */
 }
 /* }}} */
 
+/* Similar to php_dom_invalidate_node_list_cache(), but SimpleXML shouldn't depend on ext/dom. */
+static zend_always_inline void php_sxe_invalidate_node_list_cache(xmlNodePtr node)
+{
+	ZEND_ASSERT(node != NULL);
+	xmlDocPtr docp = node->doc;
+	if (docp && docp->_private) {
+		php_libxml_invalidate_node_list_cache(docp->_private);
+	}
+}
+
 static php_sxe_object* php_sxe_object_new(zend_class_entry *ce, zend_function *fptr_count);
 static xmlNodePtr php_sxe_reset_iterator(php_sxe_object *sxe, int use_data);
 static xmlNodePtr php_sxe_iterator_fetch(php_sxe_object *sxe, xmlNodePtr node, int use_data);
@@ -442,6 +452,8 @@ static zval *sxe_prop_dim_write(zend_object *object, zval *member, zval *value,
 
 	GET_NODE(sxe, node);
 
+	php_sxe_invalidate_node_list_cache(node);
+
 	if (sxe->iter.type == SXE_ITER_ATTRLIST) {
 		attribs = 1;
 		elements = 0;
@@ -813,6 +825,8 @@ static void sxe_prop_dim_delete(zend_object *object, zval *member, bool elements
 
 	GET_NODE(sxe, node);
 
+	php_sxe_invalidate_node_list_cache(node);
+
 	if (Z_TYPE_P(member) == IS_LONG) {
 		if (sxe->iter.type != SXE_ITER_ATTRLIST) {
 			attribs = 0;
@@ -1686,6 +1700,8 @@ PHP_METHOD(SimpleXMLElement, addChild)
 	sxe = Z_SXEOBJ_P(ZEND_THIS);
 	GET_NODE(sxe, node);
 
+	php_sxe_invalidate_node_list_cache(node);
+
 	if (sxe->iter.type == SXE_ITER_ATTRLIST) {
 		php_error_docref(NULL, E_WARNING, "Cannot add element to attributes");
 		return;