sdk/lib/_internal/pub/lib/src/command/downgrade.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.downgrade;

import 'dart:async';

import '../command.dart';
import '../log.dart' as log;
import '../solver/version_solver.dart';

/// Handles the `downgrade` pub command.
class DowngradeCommand extends PubCommand {
  String get description =>
      "Downgrade the current package's dependencies to oldest versions.\n\n"
      "This doesn't modify the lockfile, so it can be reset with \"pub get\".";
  String get usage => "pub downgrade [dependencies...]";
  bool get takesArguments => true;

  bool get isOffline => commandOptions['offline'];

  DowngradeCommand() {
    commandParser.addFlag('offline',
        help: 'Use cached packages instead of accessing the network.');

    commandParser.addFlag('dry-run', abbr: 'n', negatable: false,
        help: "Report what dependencies would change but don't change any.");
  }

  Future onRun() {
    var dryRun = commandOptions['dry-run'];
    return entrypoint.acquireDependencies(SolveType.DOWNGRADE,
        useLatest: commandOptions.rest, dryRun: dryRun).then((_) {
      if (isOffline) {
        log.warning("Warning: Downgrading when offline may not update you to "
            "the oldest versions of your dependencies.");
      }
    });
  }
}