fix host inheritance in some cases of file scheme in the URL polyfill

Author: zloirock

CHANGELOG.md

@@ -41,6 +41,7 @@
 - Fixed some percent encode cases / character sets in the `URL` polyfill
 - Fixed some cases of `''` and `null` host handling in the `URL` polyfill
 - Fixed host parsing with `hostname = host:port` in the `URL` polyfill
+- Fixed host inheritance in some cases of file scheme in the `URL` polyfill
 - Fixed block of protocol change for file with empty host in the `URL` polyfill
 - Fixed invalid code points handling in UTF-8 decode in the `URLSearchParams` polyfill
 - Fixed some cases of serialization in `URL` polyfill (`/.` prefix for non-special URLs with `null` host and path starting with empty segment)

packages/core-js/modules/web.url.constructor.js

@@ -643,9 +643,10 @@ URLState.prototype = {
             state = FILE_HOST;
             break;
           }
-          if (base && base.scheme === 'file' && !startsWithWindowsDriveLetter(join(arraySlice(codePoints, pointer), ''))) {
-            if (isWindowsDriveLetter(base.path[0], true)) push(url.path, base.path[0]);
-            else url.host = base.host;
+          if (base && base.scheme === 'file') {
+            url.host = base.host;
+            if (!startsWithWindowsDriveLetter(join(arraySlice(codePoints, pointer), ''))
+              && isWindowsDriveLetter(base.path[0], true)) push(url.path, base.path[0]);
           }
           state = PATH;
           continue;

tests/unit-global/web.url.js

@@ -50,6 +50,12 @@ QUnit.test('URL constructor', assert => {
   // assert.same(String(new URL('file://nnsc.nsf.net/bar/baz')), 'file://nnsc.nsf.net/bar/baz', 'file scheme'); // 'file:///bar/baz' in FF
   // assert.same(String(new URL('file://localhost/bar/baz')), 'file:///bar/baz', 'file scheme'); // 'file://localhost/bar/baz' in Chrome
 
+  // FILE_SLASH state: host should be inherited from file: base
+  // some browsers have a non-spec-compliant native URL implementation for this case
+  if (new URL('file:/path', 'file://somehost/dir/file').host === 'somehost') {
+    assert.same(new URL('file:/path', 'file://somehost/dir/file').href, 'file://somehost/path', 'file slash: href with inherited host');
+  }
+
   assert.throws(() => new URL(), 'TypeError: Failed to construct URL: 1 argument required, but only 0 present.');
   assert.throws(() => new URL(''), 'TypeError: Failed to construct URL: Invalid URL');
   // Node 19.7

tests/unit-pure/web.url.js

@@ -51,6 +51,12 @@ QUnit.test('URL constructor', assert => {
   // assert.same(String(new URL('file://nnsc.nsf.net/bar/baz')), 'file://nnsc.nsf.net/bar/baz', 'file scheme'); // 'file:///bar/baz' in FF
   // assert.same(String(new URL('file://localhost/bar/baz')), 'file:///bar/baz', 'file scheme'); // 'file://localhost/bar/baz' in Chrome
 
+  // FILE_SLASH state: host should be inherited from file: base
+  // some browsers have a non-spec-compliant native URL implementation for this case
+  if (new URL('file:/path', 'file://somehost/dir/file').host === 'somehost') {
+    assert.same(new URL('file:/path', 'file://somehost/dir/file').href, 'file://somehost/path', 'file slash: href with inherited host');
+  }
+
   assert.throws(() => new URL(), 'TypeError: Failed to construct URL: 1 argument required, but only 0 present.');
   assert.throws(() => new URL(''), 'TypeError: Failed to construct URL: Invalid URL');
   // Node 19.7