From bf553f22da96a6e61dfa9b5804af273a6b13852d Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Thu, 17 Apr 2025 14:01:53 +0200
Subject: [PATCH] Ensure that the /P-entry is actually a dictionary in
 `StructTreePage.prototype.addNode`

This may fix issue 19822, but without a test-case it's simply impossible to know for sure.
---
 src/core/struct_tree.js | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/core/struct_tree.js b/src/core/struct_tree.js
index a8766e92e..59ba40cb6 100644
--- a/src/core/struct_tree.js
+++ b/src/core/struct_tree.js
@@ -757,7 +757,10 @@ class StructTreePage {
 
     const parent = dict.get("P");
 
-    if (!parent || isName(parent.get("Type"), "StructTreeRoot")) {
+    if (
+      !(parent instanceof Dict) ||
+      isName(parent.get("Type"), "StructTreeRoot")
+    ) {
       if (!this.addTopLevelNode(dict, element)) {
         map.delete(dict);
       }