Make pub publish more user friendly:

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:io';
@@ skipping 451 matching lines @@
     if (basename(utilDir) == '') throw 'Could not find path to pub.';
     utilDir = dirname(utilDir);
   }
 
   return path.normalize(join(utilDir, 'pub', target));
 }
 
 /// A StringInputStream reading from stdin.
 final _stringStdin = new StringInputStream(stdin);
 
+/// Displays a message and reads a yes/no confirmation from the user. Returns
+/// a [Future] that completes to `true` if the user confirms or `false` if they
+/// do not.
+///
+/// This will automatically append " (y/n)?" to the message, so [message]
+/// should just be a fragment like, "Are you sure you want to proceed".
+Future<bool> confirm(String message) {
+  log.fine('Showing confirm message: $message');
+  stdout.writeString("$message (y/n)? ");
+  return readLine().transform((line) => new RegExp(r"^[yY]").hasMatch(line));
+}
+
 /// Returns a single line read from a [StringInputStream]. By default, reads
 /// from stdin.
 ///
 /// A [StringInputStream] passed to this should have no callbacks registered.
 Future<String> readLine([StringInputStream stream]) {
   if (stream == null) stream = _stringStdin;
   if (stream.closed) return new Future.immediate('');
   void removeCallbacks() {
     stream.onClosed = null;
     stream.onLine = null;
     stream.onError = null;
   }
 
   // TODO(nweiz): remove this when issue 4061 is fixed.
   var stackTrace;
   try {
     throw "";
   } catch (_, localStackTrace) {
     stackTrace = localStackTrace;
   }
 
   var completer = new Completer();
   stream.onClosed = () {
     removeCallbacks();
     completer.complete('');
   };
 
   stream.onLine = () {
     removeCallbacks();
-    completer.complete(stream.readLine());
+    var line = stream.readLine();
+    log.io('Read line: $line');
+    completer.complete(line);
   };
 
   stream.onError = (e) {
     removeCallbacks();
     completer.completeException(e, stackTrace);
   };
 
   return completer.future;
 }
 
@@ skipping 433 matching lines @@
   }).transform((_) => true);
 }
 
 /// Create a .tar.gz archive from a list of entries. Each entry can be a
 /// [String], [Directory], or [File] object. The root of the archive is
 /// considered to be [baseDir], which defaults to the current working directory.
 /// Returns an [InputStream] that will emit the contents of the archive.
 InputStream createTarGz(List contents, {baseDir}) {
   var buffer = new StringBuffer();
   buffer.add('Creating .tag.gz stream containing:\n');
-  contents.forEach(buffer.add);
+  contents.forEach((file) => buffer.add('$file\n'));
   log.fine(buffer.toString());
 
   // TODO(nweiz): Propagate errors to the returned stream (including non-zero
   // exit codes). See issue 3657.
   var stream = new ListInputStream();
 
   if (baseDir == null) baseDir = path.current;
   baseDir = getFullPath(baseDir);
   contents = contents.map((entry) {
     entry = getFullPath(entry);
@@ skipping 144 matching lines @@
   return new Directory(entry);
 }
 
 /**
  * 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 new Uri.fromString(uri);
 }