From 61baaba4e4f52ab7ebf8792228b6c92e15ae501e Mon Sep 17 00:00:00 2001
From: Ruben Bridgewater <ruben@bridgewater.de>
Date: Wed, 7 Feb 2018 02:23:40 +0100
Subject: [PATCH] assert: show proper differences

Right now it is possible to get an AssertionError from input that has
the customInspect function set to always return the same value.

That way the error message is actually misleading because the output
is going to look the same. This fixes it by deactivating the custom
inspect function.

Backport-PR-URL: https://github.com/nodejs/node/pull/19230
PR-URL: https://github.com/nodejs/node/pull/18611
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
---
 lib/internal/errors.js       | 10 ++++++----
 test/parallel/test-assert.js |  6 +++++-
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/lib/internal/errors.js b/lib/internal/errors.js
index 927e121ef3baee..f83458a6a1d70f 100644
--- a/lib/internal/errors.js
+++ b/lib/internal/errors.js
@@ -90,9 +90,9 @@ function createErrDiff(actual, expected, operator) {
   var skipped = false;
   const util = lazyUtil();
   const actualLines = util
-    .inspect(actual, { compact: false }).split('\n');
+    .inspect(actual, { compact: false, customInspect: false }).split('\n');
   const expectedLines = util
-    .inspect(expected, { compact: false }).split('\n');
+    .inspect(expected, { compact: false, customInspect: false }).split('\n');
   const msg = `Input A expected to ${operator} input B:\n` +
         `${green}+ expected${white} ${red}- actual${white}`;
   const skippedMsg = ' ... Lines skipped';
@@ -235,8 +235,10 @@ class AssertionError extends Error {
       } else if (errorDiff === 1) {
         // In case the objects are equal but the operator requires unequal, show
         // the first object and say A equals B
-        const res = util
-          .inspect(actual, { compact: false }).split('\n');
+        const res = util.inspect(
+          actual,
+          { compact: false, customInspect: false }
+        ).split('\n');
 
         if (res.length > 20) {
           res[19] = '...';
diff --git a/test/parallel/test-assert.js b/test/parallel/test-assert.js
index e3088360e3324b..96d5ff20a5ce26 100644
--- a/test/parallel/test-assert.js
+++ b/test/parallel/test-assert.js
@@ -899,7 +899,11 @@ common.expectsError(
     message: `${start}\n` +
     `${actExp}\n` +
     '\n' +
-    '  {}'
+    `${minus} {}\n` +
+    `${plus} {\n` +
+    `${plus}   loop: 'forever',\n` +
+    `${plus}   [Symbol(util.inspect.custom)]: [Function]\n` +
+    `${plus} }`
   });
 
   // notDeepEqual tests