Escape arguments in pub error message command line reproduction.

sdk/lib/_internal/pub/lib/src/command_runner.dart

 // Copyright (c) 2014, 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 pub.command_runner;
 
 import 'dart:async';
 import 'dart:io';
 
 import 'package:args/args.dart';
@@ skipping 112 matching lines @@
 
       // Explicitly exit on success to ensure that any dangling dart:io handles
       // don't cause the process to never terminate.
       await flushThenExit(exit_codes.SUCCESS);
     } catch (error, chain) {
       log.exception(error, chain);
 
       if (options['trace']) {
         log.dumpTranscript();
       } else if (!isUserFacingException(error)) {
+        // TODO(23505): Implement proper shell escaping, not a partial hack.
+        protectArgument(String x) => x.contains(' ') ? '"$x"' : x;

[nweiz, 2015/05/22 20:01:34]

Nit: don't type-annotate local variables, including parameters for local
functions.

         log.error("""
 This is an unexpected error. Please run
 
-    pub --trace ${options.arguments.map((arg) => "'$arg'").join(' ')}
+    pub --trace ${options.arguments.map(protectArgument).join(' ')}
 
 and include the results in a bug report on http://dartbug.com/new.
 """);
       }
 
       await flushThenExit(_chooseExitCode(error));
     }
   }
 
   void printUsage() {
@@ skipping 25 matching lines @@
   Future _validatePlatform() async {
     if (Platform.operatingSystem != 'windows') return;
 
     var result = await runProcess('ver', []);
     if (result.stdout.join('\n').contains('XP')) {
       log.error('Sorry, but pub is not supported on Windows XP.');
       await flushThenExit(exit_codes.USAGE);
     }
   }
 }