[bundler/bundler] Alias `cache` to `package` now

The additions of the `package` command are not actually backwards
incompatible, so we can do this transition without further care. All
existing specs of `bundle cache` pass when using the `bundle package`
implementation for it.

https://github.com/bundler/bundler/commit/69497adf90

lib/bundler/cli.rb

@@ -410,20 +410,6 @@ module Bundler
       Outdated.new(options, gems).run
     end
 
-    if Bundler.feature_flag.bundler_3_mode?
-      map %w[cache] => :package
-    else
-      desc "cache [OPTIONS]", "Cache all the gems to vendor/cache", :hide => true
-      method_option "all", :type => :boolean,
-                           :banner => "Include all sources (including path and git)."
-      method_option "all-platforms", :type => :boolean, :banner => "Include gems for all platforms present in the lockfile, not only the current one"
-      method_option "no-prune", :type => :boolean, :banner => "Don't remove stale gems from the cache."
-      def cache
-        require_relative "cli/cache"
-        Cache.new(options).run
-      end
-    end
-
     desc "#{Bundler.feature_flag.bundler_3_mode? ? :cache : :package} [OPTIONS]", "Locks and then caches all of the gems into vendor/cache"
     method_option "all",  :type => :boolean,
                           :default => Bundler.feature_flag.cache_all?,
@@ -449,7 +435,7 @@ module Bundler
       require_relative "cli/package"
       Package.new(options).run
     end
-    map %w[pack] => :package
+    map %w[cache pack] => :package
 
     desc "exec [OPTIONS]", "Run the command in context of the bundle"
     method_option :keep_file_descriptors, :type => :boolean, :default => false

lib/bundler/cli/cache.rb

@@ -1,36 +0,0 @@
-# frozen_string_literal: true
-
-module Bundler
-  class CLI::Cache
-    attr_reader :options
-    def initialize(options)
-      @options = options
-    end
-
-    def run
-      Bundler.definition.validate_runtime!
-      Bundler.definition.resolve_with_cache!
-      setup_cache_all
-      Bundler.settings.set_command_option_if_given :cache_all_platforms, options["all-platforms"]
-      Bundler.load.cache
-      Bundler.settings.set_command_option_if_given :no_prune, options["no-prune"]
-      Bundler.load.lock
-    rescue GemNotFound => e
-      Bundler.ui.error(e.message)
-      Bundler.ui.warn "Run `bundle install` to install missing gems."
-      exit 1
-    end
-
-  private
-
-    def setup_cache_all
-      Bundler.settings.set_command_option_if_given :cache_all, options[:all]
-
-      if Bundler.definition.has_local_dependencies? && !Bundler.feature_flag.cache_all?
-        Bundler.ui.warn "Your Gemfile contains path and git dependencies. If you want "    \
-          "to package them as well, please pass the --all flag. This will be the default " \
-          "on Bundler 3.0."
-      end
-    end
-  end
-end