Handle deleting broken symlinks on Windows.

utils/pub/entrypoint.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library entrypoint;
 
 import 'dart:async';
 
 import '../../pkg/pathos/lib/path.dart' as path;
 
@@ skipping 279 matching lines @@
       }).toList());
     }).then(flatten);
   }
 
   /// Creates a symlink to the `packages` directory in [dir]. Will replace one
   /// if already there.
   Future _linkSecondaryPackageDir(String dir) {
     return defer(() {
       var symlink = path.join(dir, 'packages');
       return new Future.of(() {
-        if (fileExists(symlink)) {
+        // The order of if tests is significant here. fileExists() will return
+        // true for a symlink (broken or not) but deleteFile() cannot be used
+        // to delete a broken symlink on Windows. So we test for the directory
+        // first since deleteDir() does work on symlinks.

[nweiz, 2013/03/19 19:41:02]

Can we clean up these semantics in io.dart? I'd like deleteFile to always work
on symlinks.

+        if (dirExists(symlink)) {
+          return deleteDir(symlink);
+        } else if (fileExists(symlink)) {
           deleteFile(symlink);
-        } else if (dirExists(symlink)) {
-          return deleteDir(symlink);
         }
       }).then((_) => createSymlink(packagesDir, symlink, relative: true));
     });
   }
 }