Handle deleting broken symlinks on Windows.

utils/pub/entrypoint.dart

Index: utils/pub/entrypoint.dart
diff --git a/utils/pub/entrypoint.dart b/utils/pub/entrypoint.dart
index a6afb14a2109bce79ffd3a9b0aef6481ef243e1c..fbe97c7529f666a83dccb7c498d355f76bf2f05b 100644
--- a/utils/pub/entrypoint.dart
+++ b/utils/pub/entrypoint.dart
@@ -297,10 +297,14 @@ class Entrypoint {
     return defer(() {
       var symlink = path.join(dir, 'packages');
       return new Future.of(() {
-        if (fileExists(symlink)) {
-          deleteFile(symlink);
-        } else if (dirExists(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);
         }
       }).then((_) => createSymlink(packagesDir, symlink, relative: true));
     });