Support subcommands in pub and pub help.

sdk/lib/_internal/pub/lib/src/command/lish.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.
 
 library pub.command.lish;
 
 import 'dart:async';
 
 import 'package:http/http.dart' as http;
 
 import '../command.dart';
 import '../directory_tree.dart';
-import '../exit_codes.dart' as exit_codes;
 import '../http.dart';
 import '../io.dart';
 import '../log.dart' as log;
 import '../oauth2.dart' as oauth2;
 import '../source/hosted.dart';
 import '../utils.dart';
 import '../validator.dart';
 
 /// Handles the `lish` and `publish` pub commands.
 class LishCommand extends PubCommand {
@@ skipping 63 matching lines @@
       } else if (urisEqual(Uri.parse(url.origin), Uri.parse(server.origin))) {
         handleJsonError(error.response);
       } else {
         throw error;
       }
     });
   }
 
   Future onRun() {
     if (force && dryRun) {
-      log.error('Cannot use both --force and --dry-run.');
-      this.printUsage();
-      return flushThenExit(exit_codes.USAGE);
+      usageError('Cannot use both --force and --dry-run.');
     }
 
     var packageBytesFuture = entrypoint.packageFiles().then((files) {
       log.fine('Archiving and publishing ${entrypoint.root}.');
 
       // Show the package contents so the user can verify they look OK.
       var package = entrypoint.root;
       log.message(
           'Publishing ${package.name} ${package.version} to $server:\n'
           '${generateTree(files, baseDir: entrypoint.root.dir)}');
@@ skipping 27 matching lines @@
             "${(errors.length > 1) ? 'some requirements' : 'a requirement'} "
             "and can't be published yet.\nFor more information, see: "
             "http://pub.dartlang.org/doc/pub-lish.html.\n");
         return false;
       }
 
       if (force) return true;
 
       if (dryRun) {
         var s = warnings.length == 1 ? '' : 's';
-        log.warning("Package has ${warnings.length} warning$s.");
+        log.warning("\nPackage has ${warnings.length} warning$s.");
         return false;
       }
 
-      var message = 'Looks great! Are you ready to upload your package';
+      var message = '\nLooks great! Are you ready to upload your package';
 
       if (!warnings.isEmpty) {
         var s = warnings.length == 1 ? '' : 's';
-        message = "Package has ${warnings.length} warning$s. Upload anyway";
+        message = "\nPackage has ${warnings.length} warning$s. Upload anyway";
       }
 
       return confirm(message).then((confirmed) {
         if (!confirmed) {
           log.error("Package upload canceled.");
           return false;
         }
         return true;
       });
     });
   }
 }