Cache command now prunes stale .gem files from vendor/cache

If you don't want to prune, pass --no-prune to either cache or pack

lib/bundler/cli.rb

@@ -143,15 +143,18 @@ def show(gem_name = nil)
     map %w(list) => "show"
 
     desc "cache", "Cache all the gems to vendor/cache"
+    method_option "no-prune",  :type => :boolean, :banner => "Don't remove stale gems from the cache."
     def cache
       Bundler.runtime.cache
+      Bundler.runtime.prune_cache unless options[:no_prune]
     rescue GemNotFound => e
       Bundler.ui.error(e.message)
       Bundler.ui.warn "Run `bundle install` to install missing gems."
       exit 128
     end
 
     desc "package", "Locks and then caches all of the gems into vendor/cache"
+    method_option "no-prune",  :type => :boolean, :banner => "Don't remove stale gems from the cache."
     def package
       lock
       cache

lib/bundler/runtime.rb

@@ -79,7 +79,6 @@ def dependencies_for(*groups)
     alias gems specs
 
     def cache
-      cache_path = "#{root}/vendor/cache/"
       FileUtils.mkdir_p(cache_path)
 
       Bundler.ui.info "Copying .gem files into vendor/cache"
@@ -94,12 +93,26 @@ def cache
       end
     end
 
+    def prune_cache
+      FileUtils.mkdir_p(cache_path)
+
+      Bundler.ui.info "Removing outdated .gem files from vendor/cache"
+      cache_path.children.each do |gemfile|
+        spec = Gem::Format.from_file_by_path(gemfile).spec
+        gemfile.rmtree unless specs.include?(spec)
+      end
+    end
+
   private
 
     def load_paths
       specs.map { |s| s.load_paths }.flatten
     end
 
+    def cache_path
+      root.join("vendor/cache")
+    end
+
     def write_yml_lock
       yml = details.to_yaml
       File.open("#{root}/Gemfile.lock", 'w') do |f|

spec/cache/gems_spec.rb

@@ -1,6 +1,7 @@
 require File.expand_path('../../spec_helper', __FILE__)
 
-describe "bundle cache with gems" do
+describe "bundle cache" do
+
   describe "when there are only gemsources" do
     before :each do
       gemfile <<-G
@@ -69,4 +70,51 @@
     end
   end
 
+  describe "when previously cached" do
+    before :each do
+      build_repo2
+      install_gemfile <<-G
+        source "file://#{gem_repo2}"
+        gem "rack"
+        gem "actionpack"
+      G
+      bundle :cache
+      cached_gem("rack-1.0.0").should exist
+      cached_gem("actionpack-2.3.2").should exist
+      cached_gem("activesupport-2.3.2").should exist
+    end
+
+    it "re-caches during install" do
+      cached_gem("rack-1.0.0").rmtree
+      bundle :install
+      out.should include("Copying .gem files into vendor/cache")
+      cached_gem("rack-1.0.0").should exist
+    end
+
+    it "adds updated gems" do
+      update_repo2
+      bundle :install
+      cached_gem("rack-1.2").should exist
+    end
+
+    it "adds new gems and dependencies" do
+      install_gemfile <<-G
+        source "file://#{gem_repo2}"
+        gem "rails"
+      G
+      cached_gem("rails-2.3.2").should exist
+      cached_gem("activerecord-2.3.2").should exist
+    end
+
+    it "removes .gems for removed gems and dependencies" do
+      install_gemfile <<-G
+        source "file://#{gem_repo2}"
+        gem "rack"
+      G
+      cached_gem("rack-1.0.0").should exist
+      cached_gem("actionpack-2.3.2").should_not exist
+      cached_gem("activesupport-2.3.2").should_not exist
+    end
+  end
+
 end

spec/install/gems/packed_spec.rb

@@ -32,43 +32,23 @@
       err.should be_empty
       should_be_installed "rack 1.0"
     end
-  end
 
-  describe "when cached" do
     it "ignores cached gems for the wrong platform" do
       install_gemfile <<-G
         Gem.platforms = [#{java}]
         source "file://#{gem_repo1}"
         gem "platform_specific"
       G
-      bundle :cache
+      bundle :pack
       simulate_new_machine
 
-      install_gemfile <<-G
+      install_gemfile <<-G, :relock => true
         Gem.platforms = [#{rb}]
         source "file://#{gem_repo1}"
         gem "platform_specific"
       G
-      bundle :install
       run "require 'platform_specific' ; puts PLATFORM_SPECIFIC"
       out.should == "1.0.0 RUBY"
     end
-
-    it "updates the cache during later installs" do
-      cached_gem = bundled_app("vendor/cache/rack-1.0.0.gem")
-      install_gemfile <<-G
-        source "file://#{gem_repo1}"
-        gem "rack"
-      G
-
-      bundle :cache
-      cached_gem.should exist
-
-      FileUtils.rm_rf(cached_gem)
-
-      bundle :install
-      out.should include("Copying .gem files into vendor/cache")
-      cached_gem.should exist
-    end
   end
 end

spec/support/path.rb

@@ -30,6 +30,10 @@ def bundled_app2(*path)
       root.join(*path)
     end
 
+    def cached_gem(path)
+      bundled_app("vendor/cache/#{path}.gem")
+    end
+
     def base_system_gems
       tmp.join("gems/base")
     end