From 5cb8b16452cc7379cbfd8f611b0ce471b4fcaf1f Mon Sep 17 00:00:00 2001
From: ZiJian Liu <Lxxyxzj@gmail.com>
Date: Mon, 28 Dec 2020 23:42:33 +0800
Subject: [PATCH] url: fix url.format with ipv6 hostname

Fixes: https://github.com/nodejs/node/issues/36654

PR-URL: https://github.com/nodejs/node/pull/36665
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Robert Nagy <ronagy@icloud.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Daijiro Wachi <daijiro.wachi@gmail.com>
Reviewed-By: Yash Ladha <yash@yashladha.in>
---
 lib/url.js                       | 14 +++++++++++---
 test/parallel/test-url-format.js |  6 ++++++
 2 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/lib/url.js b/lib/url.js
index cc36216f9eb916..49f99a8b5fa621 100644
--- a/lib/url.js
+++ b/lib/url.js
@@ -26,6 +26,7 @@ const {
   ObjectCreate,
   ObjectKeys,
   SafeSet,
+  StringPrototypeCharCodeAt,
 } = primordials;
 
 const { toASCII } = require('internal/idna');
@@ -156,6 +157,14 @@ function urlParse(url, parseQueryString, slashesDenoteHost) {
   return urlObject;
 }
 
+function isIpv6Hostname(hostname) {
+  return (
+    StringPrototypeCharCodeAt(hostname, 0) === CHAR_LEFT_SQUARE_BRACKET &&
+    StringPrototypeCharCodeAt(hostname, hostname.length - 1) ===
+    CHAR_RIGHT_SQUARE_BRACKET
+  );
+}
+
 Url.prototype.parse = function parse(url, parseQueryString, slashesDenoteHost) {
   validateString(url, 'url');
 
@@ -364,8 +373,7 @@ Url.prototype.parse = function parse(url, parseQueryString, slashesDenoteHost) {
 
     // If hostname begins with [ and ends with ]
     // assume that it's an IPv6 address.
-    const ipv6Hostname = hostname.charCodeAt(0) === CHAR_LEFT_SQUARE_BRACKET &&
-      hostname.charCodeAt(hostname.length - 1) === CHAR_RIGHT_SQUARE_BRACKET;
+    const ipv6Hostname = isIpv6Hostname(hostname);
 
     // validate a little.
     if (!ipv6Hostname) {
@@ -590,7 +598,7 @@ Url.prototype.format = function format() {
     host = auth + this.host;
   } else if (this.hostname) {
     host = auth + (
-      this.hostname.includes(':') ?
+      this.hostname.includes(':') && !isIpv6Hostname(this.hostname) ?
         '[' + this.hostname + ']' :
         this.hostname
     );
diff --git a/test/parallel/test-url-format.js b/test/parallel/test-url-format.js
index 2d0132eb38a0bb..720a10a97a979b 100644
--- a/test/parallel/test-url-format.js
+++ b/test/parallel/test-url-format.js
@@ -148,6 +148,12 @@ const formatTests = {
     host: '[fedc:ba98:7654:3210:fedc:ba98:7654:3210]:61616',
     pathname: '/s/stopButton'
   },
+  'http://[::]/': {
+    href: 'http://[::]/',
+    protocol: 'http:',
+    hostname: '[::]',
+    pathname: '/'
+  },
 
   // Encode context-specific delimiters in path and query, but do not touch
   // other non-delimiter chars like `%`.