From bee96124c5e00113caec0ef01240e4c328b4f26f Mon Sep 17 00:00:00 2001
From: Moonchild <moonchild@palemoon.org>
Date: Fri, 24 Apr 2026 20:38:39 +0200
Subject: [PATCH] [DOM] Avoid leaks in nsXMLPrettyPrinter.

---
 dom/xml/nsXMLPrettyPrinter.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/dom/xml/nsXMLPrettyPrinter.cpp b/dom/xml/nsXMLPrettyPrinter.cpp
index 7f1f2b07a8..3573523186 100644
--- a/dom/xml/nsXMLPrettyPrinter.cpp
+++ b/dom/xml/nsXMLPrettyPrinter.cpp
@@ -256,6 +256,8 @@ nsXMLPrettyPrinter::ContentRemoved(nsIDocument* aDocument,
 void
 nsXMLPrettyPrinter::NodeWillBeDestroyed(const nsINode* aNode)
 {
+    MOZ_DIAGNOSTIC_ASSERT(mDocument == aNode);
+    mDocument->RemoveMutationObserver(this);
     mDocument = nullptr;
     NS_RELEASE_THIS();
 }