Mute progress animation while Git is running so it doesn't overwrite credential prompts.

sdk/lib/_internal/pub/lib/src/log.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.
 
 /// Message logging.
 library pub.log;
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
@@ skipping 24 matching lines @@
 ///
 /// This can occur when the backtracking solver stumbles into a pathological
 /// dependency graph. It generally will find a solution, but it may log
 /// thousands and thousands of entries to get there.
 const _MAX_TRANSCRIPT = 10000;
 
 /// The list of recorded log messages. Will only be recorded if
 /// [recordTranscript()] is called.
 Transcript<Entry> _transcript;
 
-/// All currently-running progress indicators.
-final _progresses = new Set<Progress>();
-
 /// The currently-animated progress indicator, if any.
 ///
 /// This will also be in [_progresses].
 Progress _animatedProgress;
 
 final _cyan = getSpecial('\u001b[36m');
 final _green = getSpecial('\u001b[32m');
 final _magenta = getSpecial('\u001b[35m');
 final _red = getSpecial('\u001b[31m');
 final _yellow = getSpecial('\u001b[33m');
@@ skipping 309 matching lines @@
 
 /// Prints [message] then displays an updated elapsed time until the future
 /// returned by [callback] completes.
 ///
 /// If anything else is logged during this (including another call to
 /// [progress]) that cancels the progress animation, although the total time
 /// will still be printed once it finishes. If [fine] is passed, the progress
 /// information will only be visible at [Level.FINE].
 Future progress(String message, Future callback(), {bool fine: false}) {
   _stopProgress();
+
   var progress = new Progress(message, fine: fine);
   _animatedProgress = progress;
-  _progresses.add(progress);
-  return callback().whenComplete(() {
-    progress.stop();
-    _progresses.remove(progress);
-  });
+  return callback().whenComplete(progress.stop);
 }
 
 /// Stops animating the running progress indicator, if currently running.
 void _stopProgress() {
   if (_animatedProgress != null) _animatedProgress.stopAnimating();
   _animatedProgress = null;
 }
 
+/// The number of outstanding calls to [muteProgress] that have not been unmuted
+/// yet.
+int _numMutes = 0;
+
+/// Whether progress animation should be muted or not.
+bool get isMuted => _numMutes > 0;
+
+/// Stops animating any ongoing progress.
+///
+/// This is called before spawning Git since Git sometimes writes directly to
+/// the terminal to ask for login credentials, which would then get overwritten
+/// by the progress animation.
+///
+/// Each call to this must be paired with a call to [unmuteProgress].
+void muteProgress() {
+  _numMutes++;
+}
+
+/// Resumes animating any ongoing progress once all calls to [muteProgress]
+/// have made their matching [unmuteProgress].
+void unmuteProgress() {
+  _numMutes--;

[Jacob, 2015/01/08 23:46:25]

nit:
consider adding

assert(_numMutes > 0); 

[Bob Nystrom, 2015/01/08 23:58:19]

Done.

+}
+
 /// Wraps [text] in the ANSI escape codes to make it bold when on a platform
 /// that supports that.
 ///
 /// Use this to highlight the most important piece of a long chunk of text.
 ///
 /// This is disabled under [withPrejudice] since all text is bold with
 /// prejudice.
 String bold(text) => withPrejudice ? text : "$_bold$text$_none";
 
 /// Wraps [text] in the ANSI escape codes to make it gray when on a platform
@@ skipping 116 matching lines @@
     this.message(errorJson);
   }
 
   /// Encodes [message] to JSON and prints it if JSON output is enabled.
   void message(message) {
     if (!enabled) return;
 
     print(JSON.encode(message));
   }
 }