lib: make `IterableWeakMap` safe to iterate

PR-URL: https://github.com/nodejs/node/pull/38523
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

1 files changed, 7 insertions, 1 deletions

diff --git a/test/parallel/test-internal-iterable-weak-map.js b/test/parallel/test-internal-iterable-weak-map.js
index e0282c9081..f2befe13da 100644
--- a/test/parallel/test-internal-iterable-weak-map.js
+++ b/test/parallel/test-internal-iterable-weak-map.js
@@ -1,10 +1,16 @@
 // Flags: --expose-gc --expose-internals
 'use strict';
 
-require('../common');
+const common = require('../common');
 const { deepStrictEqual, strictEqual } = require('assert');
 const { IterableWeakMap } = require('internal/util/iterable_weak_map');
 
+// Ensures iterating over the map does not rely on methods which can be
+// mutated by users.
+Reflect.getPrototypeOf(function*() {}).prototype.next = common.mustNotCall();
+Reflect.getPrototypeOf(new Set()[Symbol.iterator]()).next =
+  common.mustNotCall();
+
 // It drops entry if a reference is no longer held.
 {
   const wm = new IterableWeakMap();