Make requiring gems optional.

Signed-off-by: Michael Koziarski <michael@koziarski.com>
[#743 state:resolved]

railties/lib/initializer.rb

@@ -688,13 +688,17 @@ Run `rake gems:install` to install the missing gems.
     # You can add gems with the #gem method.
     attr_accessor :gems
 
-    # Adds a single Gem dependency to the rails application.
+    # Adds a single Gem dependency to the rails application. By default, it will require
+    # the library with the same name as the gem. Use :lib to specify a different name.
     #
     #   # gem 'aws-s3', '>= 0.4.0'
     #   # require 'aws/s3'
     #   config.gem 'aws-s3', :lib => 'aws/s3', :version => '>= 0.4.0', \
     #     :source => "http://code.whytheluckystiff.net"
     #
+    # To require a library be installed, but not attempt to load it, pass :lib => false
+    #
+    #   config.gem 'qrp', :version => '0.4.1', :lib => false
     def gem(name, options = {})
       @gems << Rails::GemDependency.new(name, options)
     end

railties/lib/rails/gem_dependency.rb

@@ -58,7 +58,7 @@ module Rails
 
     def load
       return if @loaded || @load_paths_added == false
-      require(@lib || @name)
+      require(@lib || @name) unless @lib == false
       @loaded = true
     rescue LoadError
       puts $!.to_s

railties/test/gem_dependency_test.rb

@@ -11,6 +11,7 @@ uses_mocha "Plugin Tests" do
       @gem_with_source  = Rails::GemDependency.new "hpricot", :source => "http://code.whytheluckystiff.net"
       @gem_with_version = Rails::GemDependency.new "hpricot", :version => "= 0.6"
       @gem_with_lib     = Rails::GemDependency.new "aws-s3", :lib => "aws/s3"
+      @gem_without_load  = Rails::GemDependency.new "hpricot", :lib => false
     end
 
     def test_configuration_adds_gem_dependency
@@ -62,5 +63,13 @@ uses_mocha "Plugin Tests" do
       @gem_with_lib.add_load_paths
       @gem_with_lib.load
     end
+
+    def test_gem_without_lib_loading
+      @gem_without_load.expects(:gem).with(@gem_without_load.name)
+      @gem_without_load.expects(:require).with(@gem_without_load.lib).never
+      @gem_without_load.add_load_paths
+      @gem_without_load.load
+    end
+
   end
 end