url: reuse existing context in href setter

Correctness-wise, this removes side effects in the href setter if
parsing fails. Style-wise, this allows removing the parse() wrapper
function around C++ _parse().

Also fix an existing bug with whitespace trimming in C++ that was
previously circumvented by additionally trimming the input in
JavaScript.

Fixes: https://github.com/nodejs/node/issues/24345
Refs: https://github.com/nodejs/node/pull/24218#issuecomment-438476591

PR-URL: https://github.com/nodejs/node/pull/24495
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: Franziska Hinkelmann <franziska.hinkelmann@gmail.com>
Reviewed-By: Daijiro Wachi <daijiro.wachi@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

lib/internal/url.js

@@ -43,7 +43,7 @@ const {
   domainToUnicode: _domainToUnicode,
   encodeAuth,
   toUSVString: _toUSVString,
-  parse: _parse,
+  parse,
   setURLConstructor,
   URL_FLAGS_CANNOT_BE_BASE,
   URL_FLAGS_HAS_FRAGMENT,
@@ -243,14 +243,6 @@ function onParseError(flags, input) {
   throw error;
 }
 
-// Reused by URL constructor and URL#href setter.
-function parse(url, input, base) {
-  const base_context = base ? base[context] : undefined;
-  url[context] = new URLContext();
-  _parse(input.trim(), -1, base_context, undefined,
-         onParseComplete.bind(url), onParseError);
-}
-
 function onParseProtocolComplete(flags, protocol, username, password,
                                  host, port, path, query, fragment) {
   const ctx = this[context];
@@ -319,10 +311,13 @@ class URL {
   constructor(input, base) {
     // toUSVString is not needed.
     input = `${input}`;
+    let base_context;
     if (base !== undefined) {
-      base = new URL(base);
+      base_context = new URL(base)[context];
     }
-    parse(this, input, base);
+    this[context] = new URLContext();
+    parse(input, -1, base_context, undefined, onParseComplete.bind(this),
+          onParseError);
   }
 
   get [special]() {
@@ -445,7 +440,8 @@ Object.defineProperties(URL.prototype, {
     set(input) {
       // toUSVString is not needed.
       input = `${input}`;
-      parse(this, input);
+      parse(input, -1, undefined, undefined, onParseComplete.bind(this),
+            onParseError);
     }
   },
   origin: {  // readonly
@@ -491,8 +487,8 @@ Object.defineProperties(URL.prototype, {
           (ctx.host === '' || ctx.host === null)) {
         return;
       }
-      _parse(scheme, kSchemeStart, null, ctx,
+      parse(scheme, kSchemeStart, null, ctx,
-             onParseProtocolComplete.bind(this));
+            onParseProtocolComplete.bind(this));
     }
   },
   username: {
@@ -555,7 +551,7 @@ Object.defineProperties(URL.prototype, {
         // Cannot set the host if cannot-be-base is set
         return;
       }
-      _parse(host, kHost, null, ctx, onParseHostComplete.bind(this));
+      parse(host, kHost, null, ctx, onParseHostComplete.bind(this));
     }
   },
   hostname: {
@@ -572,7 +568,7 @@ Object.defineProperties(URL.prototype, {
         // Cannot set the host if cannot-be-base is set
         return;
       }
-      _parse(host, kHostname, null, ctx, onParseHostnameComplete.bind(this));
+      parse(host, kHostname, null, ctx, onParseHostnameComplete.bind(this));
     }
   },
   port: {
@@ -592,7 +588,7 @@ Object.defineProperties(URL.prototype, {
         ctx.port = null;
         return;
       }
-      _parse(port, kPort, null, ctx, onParsePortComplete.bind(this));
+      parse(port, kPort, null, ctx, onParsePortComplete.bind(this));
     }
   },
   pathname: {
@@ -611,8 +607,8 @@ Object.defineProperties(URL.prototype, {
       path = `${path}`;
       if (this[cannotBeBase])
         return;
-      _parse(path, kPathStart, null, this[context],
+      parse(path, kPathStart, null, this[context],
-             onParsePathComplete.bind(this));
+            onParsePathComplete.bind(this));
     }
   },
   search: {
@@ -635,7 +631,7 @@ Object.defineProperties(URL.prototype, {
         ctx.query = '';
         ctx.flags |= URL_FLAGS_HAS_QUERY;
         if (search) {
-          _parse(search, kQuery, null, ctx, onParseSearchComplete.bind(this));
+          parse(search, kQuery, null, ctx, onParseSearchComplete.bind(this));
         }
       }
       initSearchParams(this[searchParams], search);
@@ -669,7 +665,7 @@ Object.defineProperties(URL.prototype, {
       if (hash[0] === '#') hash = hash.slice(1);
       ctx.fragment = '';
       ctx.flags |= URL_FLAGS_HAS_FRAGMENT;
-      _parse(hash, kFragment, null, ctx, onParseHashComplete.bind(this));
+      parse(hash, kFragment, null, ctx, onParseHashComplete.bind(this));
     }
   },
   toJSON: {

src/node_url.cc

@@ -1376,6 +1376,7 @@ void URL::Parse(const char* input,
       else
         break;
     }
+    input = p;
     len = end - p;
   }
 

test/parallel/test-whatwg-url-custom-href-side-effect.js

@@ -0,0 +1,15 @@
+'use strict';
+
+// Tests below are not from WPT.
+const common = require('../common');
+const assert = require('assert');
+
+const ref = new URL('http://example.com/path');
+const url = new URL('http://example.com/path');
+common.expectsError(() => {
+  url.href = '';
+}, {
+  type: TypeError
+});
+
+assert.deepStrictEqual(url, ref);