From bd03f1ca70b0fe2d3ed22d98af2e83d8cbcf5f43 Mon Sep 17 00:00:00 2001
From: "Davide P. Cervone" <dpvc@union.edu>
Date: Thu, 14 Sep 2023 10:08:11 -0400
Subject: [PATCH] Prevent setting a propery that has a getter. 
 (mathjax/MathJax#3098)

---
 ts/components/global.ts | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/ts/components/global.ts b/ts/components/global.ts
index 65825b611..adec367c2 100644
--- a/ts/components/global.ts
+++ b/ts/components/global.ts
@@ -78,18 +78,21 @@ export function isObject(x: any): boolean {
  * Combine user-produced configuration with existing defaults.  Values
  * from src will replace those in dst.
  *
- * @param {any} dst      The destination config object (to be merged into)
- * @param {any} src      The source configuration object (to replace defaul values in dst}
- * @return {any}         The resulting (modified) config object
+ * @param {any} dst         The destination config object (to be merged into)
+ * @param {any} src         The source configuration object (to replace defaul values in dst}
+ * @param {boolean} check   True when combining into MathJax._ to avoid setting getter properties
+ * @return {any}            The resulting (modified) config object
  */
-export function combineConfig(dst: any, src: any): any {
+export function combineConfig(dst: any, src: any, check: boolean = false): any {
   for (const id of Object.keys(src)) {
-    if (id === '__esModule') continue;
+    if (id === '__esModule' || dst[id] === src[id]) continue;
     if (isObject(dst[id]) && isObject(src[id]) &&
         !(src[id] instanceof Promise) /* needed for IE polyfill */) {
-      combineConfig(dst[id], src[id]);
-    } else if (src[id] !== null && src[id] !== undefined && dst[id] !== src[id]) {
-      dst[id] = src[id];
+      combineConfig(dst[id], src[id], check || id === '_');
+    } else if (src[id] !== null && src[id] !== undefined) {
+      if (!check || !Object.getOwnPropertyDescriptor(dst, id)?.get) {
+        dst[id] = src[id];
+      }
     }
   }
   return dst;