url: fix url.parse() for @hostname

Make url.parse() behave more like browsers and WHATWHG URL when dealing
with URLs that of the format `http:@example.com`. This is the same as
`http://example.com`.

This issue was reported by P0cas. https://github.com/P0cas

PR-URL: nodejs#42136
Reviewed-By: Darshan Sen <raisinten@gmail.com>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>

lib/url.js

@@ -294,22 +294,29 @@ Url.prototype.parse = function parse(url, parseQueryString, slashesDenoteHost) {
     rest = rest.slice(proto.length);
   }
 
-  // Figure out if it's got a host
-  // user@server is *always* interpreted as a hostname, and url
+  // Figure out if it's got a host.
+  // user@server is *always* interpreted as a hostname, and URL
   // resolution will treat //foo/bar as host=foo,path=bar because that's
-  // how the browser resolves relative URLs.
+  // how the browser resolves relative URLs. http:@example.com is treated
+  // the same as http://example.com.
   let slashes;
+  let at;
   if (slashesDenoteHost || proto || hostPattern.test(rest)) {
     slashes = rest.charCodeAt(0) === CHAR_FORWARD_SLASH &&
-              rest.charCodeAt(1) === CHAR_FORWARD_SLASH;
-    if (slashes && !(proto && hostlessProtocol.has(lowerProto))) {
-      rest = rest.slice(2);
-      this.slashes = true;
+                  rest.charCodeAt(1) === CHAR_FORWARD_SLASH;
+    at = rest.charCodeAt(0) === CHAR_AT;
+    if (!(proto && hostlessProtocol.has(lowerProto))) {
+      if (slashes) {
+        rest = rest.slice(2);
+        this.slashes = true;
+      } else if (at) {
+        rest = rest.slice(1);
+      }
     }
   }
 
   if (!hostlessProtocol.has(lowerProto) &&
-      (slashes || (proto && !slashedProtocol.has(proto)))) {
+      (slashes || at || (proto && !slashedProtocol.has(proto)))) {
 
     // there's a hostname.
     // the first instance of /, ?, ;, or # ends the host.

test/parallel/test-url-parse-format.js

@@ -975,7 +975,22 @@ const parseTests = {
     query: null,
     pathname: '/everybody',
     path: '/everybody',
-    href: '//fhqwhgads@example.com/everybody#to-the-limit'
+    href: '//fhqwhgads@example.com/everybody#to-the-limit',
+  },
+
+  'http:@localhost': {
+    protocol: 'http:',
+    slashes: null,
+    auth: null,
+    host: 'localhost',
+    port: null,
+    hostname: 'localhost',
+    hash: null,
+    search: null,
+    query: null,
+    pathname: '/',
+    path: '/',
+    href: 'http://localhost/',
   },
 };