fix: 🐛 request.url getter fails when using bare IPv6 hosts ([#4556](#4556))

Author: gsoldevila

lib/request.js

@@ -183,8 +183,13 @@ exports = module.exports = internals.Request = class {
                 this._normalizePath(url, options);
                 return url;
             }
+            else {
+
+                const hostname = this._formatIpv6Host(this.info.host || this._core.info.host);
+                const hostPort = this.info.host ? hostname : `${hostname}:${this._core.info.port}`;
 
-            this._url = new Url.URL(`${this._core.info.protocol}://${this.info.host || `${this._core.info.host}:${this._core.info.port}`}${source}`);
+                this._url = new Url.URL(`${this._core.info.protocol}://${hostPort}${source}`);
+            }
         }
         else {
 
@@ -201,6 +206,25 @@ exports = module.exports = internals.Request = class {
         return this._url;
     }
 
+    _isBareIpv6(host) {
+
+        // If it's already bracketed, it's not a 'bare' IPv6 we need to wrap.
+
+        if (host.startsWith('[') && host.endsWith(']')) {
+            return false;
+        }
+
+        // An IPv6 address must contain at least two colons.
+
+        const colonCount = (host.match(/:/g) || []).length;
+        return colonCount >= 2;
+    }
+
+    _formatIpv6Host(host) {
+
+        return this._isBareIpv6(host) ? `[${host}]`: host;
+    }
+
     _normalizePath(url, options) {
 
         let path = this._core.router.normalize(url.pathname);