From 54364ca727bb70f9ee85f812129cb40045fdf829 Mon Sep 17 00:00:00 2001
From: Niels Dossche <7771979+nielsdos@users.noreply.github.com>
Date: Thu, 11 Jul 2024 18:07:17 +0200
Subject: [PATCH] Avoid reconciling when cloning into the same document

We don't need to reconcile when we clone into the same document because
the namespace mapper is the same. Only when cloning into another
document is the namespace mapper different and do we need a
reconciliation.
---
 ext/dom/php_dom.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/ext/dom/php_dom.c b/ext/dom/php_dom.c
index e6e7a23600d94..f61b362d26baa 100644
--- a/ext/dom/php_dom.c
+++ b/ext/dom/php_dom.c
@@ -2567,7 +2567,9 @@ xmlNodePtr dom_clone_node(php_dom_libxml_ns_mapper *ns_mapper, xmlNodePtr node,
 
 	if (ns_mapper != NULL) {
 		xmlNodePtr clone = dom_clone_helper(ns_mapper, node, doc, recursive);
-		if (EXPECTED(clone != NULL)) {
+		if (EXPECTED(clone != NULL) && doc != node->doc) {
+			/* We only need to reconcile the namespace when the document changes because the namespaces have to be
+			 * put into their respective namespace mapper. */
 			if (clone->type == XML_DOCUMENT_NODE || clone->type == XML_HTML_DOCUMENT_NODE || clone->type == XML_DOCUMENT_FRAG_NODE) {
 				for (xmlNodePtr child = clone->children; child != NULL; child = child->next) {
 					php_dom_libxml_reconcile_modern(ns_mapper, child);