Handle broken symlinks when creating package dirs.

utils/pub/io.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.
 
 /// Helper functionality to make working with IO easier.
 library io;
 
 import 'dart:async';
 import 'dart:io';
 import 'dart:isolate';
@@ skipping 11 matching lines @@
 
 final NEWLINE_PATTERN = new RegExp("\r\n?|\n\r?");
 
 /// Returns whether or not [entry] is nested somewhere within [dir]. This just
 /// performs a path comparison; it doesn't look at the actual filesystem.
 bool isBeneath(String entry, String dir) {
   var relative = path.relative(entry, from: dir);
   return !path.isAbsolute(relative) && path.split(relative)[0] != '..';
 }
 
-/// Determines if a file or directory at [path] exists.
-bool entryExists(String path) => fileExists(path) || dirExists(path);
+/// Determines if a file or directory exists at [path].
+bool entryExists(String path) => dirExists(path) || fileExists(path);
 
-/// Determines if [file] exists on the file system.
-bool fileExists(String file) => new File(file).existsSync();
+/// Determines if [file] exists on the file system. Will also return `true` if
+/// [file] points to a symlink, even a directory symlink.
+bool fileExists(String file) =>
+    new File(file).existsSync() || new Link(file).existsSync();
 
 /// Reads the contents of the text file [file].
 String readTextFile(String file) =>
     new File(file).readAsStringSync(Encoding.UTF_8);
 
 /// Reads the contents of the binary file [file].
 List<int> readBinaryFile(String file) {
   log.io("Reading binary file $file.");
   var contents = new File(file).readAsBytesSync();
   log.io("Read ${contents.length} bytes from $file.");
@@ skipping 158 matching lines @@
 bool dirExists(String dir) => new Directory(dir).existsSync();
 
 /// "Cleans" [dir]. If that directory already exists, it will be deleted. Then a
 /// new empty directory will be created. Returns a [Future] that completes when
 /// the new clean directory is created.
 Future<String> cleanDir(String dir) {
   return defer(() {
     if (dirExists(dir)) {
       // Delete it first.
       return deleteDir(dir).then((_) => createDir(dir));
-    } else {
-      // Just create it.
+    }
+
+    if (fileExists(dir)) {
+      // If there is a non-directory there (file or symlink), delete it.
+      deleteFile(dir);
       return createDir(dir);
     }
+
+    // Just create it.
+    return createDir(dir);
   });
 }
 
 /// Renames (i.e. moves) the directory [from] to [to]. Returns a [Future] with
 /// the destination directory.
 Future<String> renameDir(String from, String to) {
   log.io("Renaming directory $from to $to.");
 
   return _attemptRetryable(() => new Directory(from).rename(to)).then((dir) {
     log.fine("Renamed directory $from to $to.");
@@ skipping 573 matching lines @@
   const PubProcessResult(this.stdout, this.stderr, this.exitCode);
 
   bool get success => exitCode == 0;
 }
 
 /// Gets a [Uri] for [uri], which can either already be one, or be a [String].
 Uri _getUri(uri) {
   if (uri is Uri) return uri;
   return Uri.parse(uri);
 }