From 74db9f43ba0cd451af165b820b59c336814fe6f2 Mon Sep 17 00:00:00 2001
From: Ruben Bridgewater <ruben@bridgewater.de>
Date: Mon, 7 May 2018 03:53:02 +0200
Subject: [PATCH] assert,util: lazy load comparison functions

PR-URL: https://github.com/nodejs/node/pull/20567
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>
---
 lib/assert.js | 18 ++++++++++++++----
 lib/util.js   | 13 ++++++++-----
 2 files changed, 22 insertions(+), 9 deletions(-)

diff --git a/lib/assert.js b/lib/assert.js
index 8ed90608d8f88d..98900c5151ed41 100644
--- a/lib/assert.js
+++ b/lib/assert.js
@@ -21,10 +21,6 @@
 'use strict';
 
 const { Buffer } = require('buffer');
-const {
-  isDeepEqual,
-  isDeepStrictEqual
-} = require('internal/util/comparisons');
 const { codes: {
   ERR_AMBIGUOUS_ARGUMENT,
   ERR_INVALID_ARG_TYPE,
@@ -36,6 +32,15 @@ const { inspect, types: { isPromise, isRegExp } } = require('util');
 const { EOL } = require('internal/constants');
 const { NativeModule } = require('internal/bootstrap/loaders');
 
+let isDeepEqual;
+let isDeepStrictEqual;
+
+function lazyLoadComparison() {
+  const comparison = require('internal/util/comparisons');
+  isDeepEqual = comparison.isDeepEqual;
+  isDeepStrictEqual = comparison.isDeepStrictEqual;
+}
+
 // Escape control characters but not \n and \t to keep the line breaks and
 // indentation intact.
 // eslint-disable-next-line no-control-regex
@@ -284,6 +289,7 @@ assert.notEqual = function notEqual(actual, expected, message) {
 
 // The equivalence assertion tests a deep equality relation.
 assert.deepEqual = function deepEqual(actual, expected, message) {
+  if (isDeepEqual === undefined) lazyLoadComparison();
   if (!isDeepEqual(actual, expected)) {
     innerFail({
       actual,
@@ -297,6 +303,7 @@ assert.deepEqual = function deepEqual(actual, expected, message) {
 
 // The non-equivalence assertion tests for any deep inequality.
 assert.notDeepEqual = function notDeepEqual(actual, expected, message) {
+  if (isDeepEqual === undefined) lazyLoadComparison();
   if (isDeepEqual(actual, expected)) {
     innerFail({
       actual,
@@ -310,6 +317,7 @@ assert.notDeepEqual = function notDeepEqual(actual, expected, message) {
 /* eslint-enable */
 
 assert.deepStrictEqual = function deepStrictEqual(actual, expected, message) {
+  if (isDeepEqual === undefined) lazyLoadComparison();
   if (!isDeepStrictEqual(actual, expected)) {
     innerFail({
       actual,
@@ -323,6 +331,7 @@ assert.deepStrictEqual = function deepStrictEqual(actual, expected, message) {
 
 assert.notDeepStrictEqual = notDeepStrictEqual;
 function notDeepStrictEqual(actual, expected, message) {
+  if (isDeepEqual === undefined) lazyLoadComparison();
   if (isDeepStrictEqual(actual, expected)) {
     innerFail({
       actual,
@@ -439,6 +448,7 @@ function expectedException(actual, expected, msg) {
     if (expected instanceof Error) {
       keys.push('name', 'message');
     }
+    if (isDeepEqual === undefined) lazyLoadComparison();
     for (const key of keys) {
       if (typeof actual[key] === 'string' &&
           isRegExp(expected[key]) &&
diff --git a/lib/util.js b/lib/util.js
index 45d98de194c836..bd7a98694b91a9 100644
--- a/lib/util.js
+++ b/lib/util.js
@@ -64,10 +64,6 @@ const {
   isTypedArray
 } = types;
 
-const {
-  isDeepStrictEqual
-} = require('internal/util/comparisons');
-
 const {
   customInspectSymbol,
   deprecate,
@@ -95,6 +91,7 @@ const dateToISOString = Date.prototype.toISOString;
 const errorToString = Error.prototype.toString;
 
 let CIRCULAR_ERROR_MESSAGE;
+let internalDeepEqual;
 
 /* eslint-disable */
 const strEscapeSequencesRegExp = /[\x00-\x1f\x27\x5c]/;
@@ -1261,7 +1258,13 @@ module.exports = exports = {
   isArray: Array.isArray,
   isBoolean,
   isBuffer,
-  isDeepStrictEqual,
+  isDeepStrictEqual(a, b) {
+    if (internalDeepEqual === undefined) {
+      internalDeepEqual = require('internal/util/comparisons')
+        .isDeepStrictEqual;
+    }
+    return internalDeepEqual(a, b);
+  },
   isNull,
   isNullOrUndefined,
   isNumber,