From be7195c59cc2eaba4ba322ccbdf3264d988a4253 Mon Sep 17 00:00:00 2001
From: Ruben Bridgewater <ruben@bridgewater.de>
Date: Fri, 11 Aug 2017 14:30:37 -0300
Subject: [PATCH] util: fix circular ref for Set and Map

Fixes #14758
---
 lib/util.js                        | 12 +++++++++---
 test/parallel/test-util-inspect.js | 19 +++++++++++++++++++
 2 files changed, 28 insertions(+), 3 deletions(-)

diff --git a/lib/util.js b/lib/util.js
index a9f267bd416ddc..38bd8dd7daa105 100644
--- a/lib/util.js
+++ b/lib/util.js
@@ -738,7 +738,9 @@ function formatSet(ctx, value, recurseTimes, visibleKeys, keys) {
   var output = [];
   value.forEach(function(v) {
     var nextRecurseTimes = recurseTimes === null ? null : recurseTimes - 1;
-    var str = formatValue(ctx, v, nextRecurseTimes);
+    var str = ctx.seen.includes(v) ?
+      ctx.stylize('[Circular]', 'special') :
+      formatValue(ctx, v, nextRecurseTimes);
     output.push(str);
   });
   for (var n = 0; n < keys.length; n++) {
@@ -753,9 +755,13 @@ function formatMap(ctx, value, recurseTimes, visibleKeys, keys) {
   var output = [];
   value.forEach(function(v, k) {
     var nextRecurseTimes = recurseTimes === null ? null : recurseTimes - 1;
-    var str = formatValue(ctx, k, nextRecurseTimes);
+    var str = ctx.seen.includes(k) ?
+      ctx.stylize('[Circular]', 'special') :
+      formatValue(ctx, k, nextRecurseTimes);
     str += ' => ';
-    str += formatValue(ctx, v, nextRecurseTimes);
+    str += ctx.seen.includes(v) ?
+      ctx.stylize('[Circular]', 'special') :
+      formatValue(ctx, v, nextRecurseTimes);
     output.push(str);
   });
   for (var n = 0; n < keys.length; n++) {
diff --git a/test/parallel/test-util-inspect.js b/test/parallel/test-util-inspect.js
index df9e3d7f7def4d..7e25331efd986e 100644
--- a/test/parallel/test-util-inspect.js
+++ b/test/parallel/test-util-inspect.js
@@ -783,6 +783,13 @@ if (typeof Symbol !== 'undefined') {
   );
 }
 
+// Test circular Set
+{
+  const set = new Set();
+  set.add(set);
+  assert.strictEqual(util.inspect(set), 'Set { [Circular] }');
+}
+
 // test Map
 {
   assert.strictEqual(util.inspect(new Map()), 'Map {}');
@@ -794,6 +801,18 @@ if (typeof Symbol !== 'undefined') {
                      'Map { \'foo\' => null, [size]: 1, bar: 42 }');
 }
 
+// Test circular Map
+{
+  const map = new Map();
+  map.set(map, 'map');
+  assert.strictEqual(util.inspect(map), "Map { [Circular] => 'map' }");
+  map.set(map, map);
+  assert.strictEqual(util.inspect(map), 'Map { [Circular] => [Circular] }');
+  map.delete(map);
+  map.set('map', map);
+  assert.strictEqual(util.inspect(map), "Map { 'map' => [Circular] }");
+}
+
 // test Promise
 {
   const resolved = Promise.resolve(3);