From 1ee2d1f51a27bf74ce74aac06a96777d18976ee9 Mon Sep 17 00:00:00 2001
From: Ruben Bridgewater <ruben.bridgewater@datadoghq.com>
Date: Thu, 15 Jan 2026 01:51:15 +0100
Subject: [PATCH] assert,util: fix deep comparison for sets and maps with mixed
 types

When comparing a Set or a Map and they contain primitives as keys
as well as objects, the primitives would always be skipped. That
is not correct, since that may only be skipped in case all keys
are objects.

Fixes: https://github.com/nodejs/node/issues/61386
---
 lib/internal/util/comparisons.js  | 17 +++++++++++------
 test/parallel/test-assert-deep.js | 15 +++++++++++++++
 2 files changed, 26 insertions(+), 6 deletions(-)

diff --git a/lib/internal/util/comparisons.js b/lib/internal/util/comparisons.js
index 754e0b1d5d44bd..a8d5178242fdc8 100644
--- a/lib/internal/util/comparisons.js
+++ b/lib/internal/util/comparisons.js
@@ -669,8 +669,10 @@ function setObjectEquiv(array, a, b, mode, memo) {
         if (b.has(val1)) {
           continue;
         }
-      } else if (mode !== kLoose || b.has(val1)) {
+      } else if (b.has(val1)) {
         continue;
+      } else if (mode !== kLoose) {
+        return false;
       }
     }
 
@@ -816,11 +818,14 @@ function mapObjectEquiv(array, a, b, mode, memo) {
   const extraChecks = mode === kLoose || array.length !== a.size;
 
   for (const { 0: key1, 1: item1 } of a) {
-    if (extraChecks &&
-        (typeof key1 !== 'object' || key1 === null) &&
-        (mode !== kLoose ||
-          (b.has(key1) && innerDeepEqual(item1, b.get(key1), mode, memo)))) { // Mixed mode
-      continue;
+    if (extraChecks && (typeof key1 !== 'object' || key1 === null)) {
+      if (b.has(key1)) {
+        if (mode !== kLoose || innerDeepEqual(item1, b.get(key1), mode, memo)) {
+          continue;
+        }
+      } else if (mode !== kLoose) {
+        return false;
+      }
     }
 
     let innerStart = start;
diff --git a/test/parallel/test-assert-deep.js b/test/parallel/test-assert-deep.js
index 9c1d8eefe09252..c1a42aa4de624d 100644
--- a/test/parallel/test-assert-deep.js
+++ b/test/parallel/test-assert-deep.js
@@ -634,6 +634,21 @@ test('Handle sparse arrays', () => {
   assertNotDeepOrStrict(a, b, AssertionError, { partial: 'pass' });
 });
 
+test('Handle sets and maps with mixed keys', () => {
+  // https://github.com/nodejs/node/issues/61386
+  const aSet = new Set([0, new Set([1, 2, 3]), new Set([4, 5, 6])]);
+  const bSet = new Set([
+    0,
+    new Set([1, new Set([2, 3]), new Set([20, 30])]),
+    new Set([4, new Set([5, 6]), new Set([50, 60])]),
+  ]);
+  assertNotDeepOrStrict(aSet, bSet);
+
+  const aMap = new Map([[0, 'zero'], [1, 'one'], [new Set([1, 2, 3]), 'A']]);
+  const bMap = new Map([[0, 'zero'], [new Set([1, 2, 3]), 'A'], [new Set([9]), 'B']]);
+  assertNotDeepOrStrict(aMap, bMap);
+});
+
 test('Handle different error messages', () => {
   const err1 = new Error('foo1');
   assertNotDeepOrStrict(err1, new Error('foo2'), assert.AssertionError);