Configuration files are only loaded once

lib/vagrant/config/container.rb

@@ -7,7 +7,31 @@ module Vagrant
     # the completely loaded configuration values. This class is meant to
     # be immutable.
     class Container
+      # Initializes the configuration container.
+      #
+      # A `Vagrant::Config::top` should be passed in to initialize this.
+      # The container will use this top in order to separate and provide
+      # access to the configuration.
+      def initialize(top)
+        @top = top
+      end
 
+      # This returns the global configuration values. These are values
+      # that apply to the system as a whole, and not to a specific virtual
+      # machine or so on. Examples of this sort of configuration: the
+      # class of the host system, name of the Vagrant dotfile, etc.
+      def global
+        # For now, we just return all the configuration, until we
+        # separate out global vs. non-global configuration keys.
+        @top
+      end
+
+      # This returns the configuration for a specific virtual machine.
+      # The values for this configuration are usually pertinent to a
+      # single virtual machine and do not affect the system globally.
+      def for_vm(name)
+        @top
+      end
     end
   end
 end

lib/vagrant/config/loader.rb

@@ -19,6 +19,7 @@ module Vagrant
       def initialize
         @logger  = Log4r::Logger.new("vagrant::config::loader")
         @sources = {}
+        @proc_cache = {}
       end
 
       # Set the configuration data for the given name.
@@ -56,7 +57,16 @@ module Vagrant
         @load_order.each do |key|
           @sources[key].each do |source|
             @logger.debug("Loading from: #{key}")
-            procs_for_source(source).each do |proc|
+
+            # Load the procs, caching them by the source key. This makes
+            # sure that files are only loaded once, for example. The reason
+            # for this is because people may put side-effect code in their
+            # Vagrantfiles. This assures that the side effect only occurs
+            # once (which is what they expect)
+            @proc_cache[key] ||= procs_for_source(source)
+
+            # Call each proc with the top-level configuration.
+            @proc_cache[key].each do |proc|
               proc.call(top)
             end
           end

test/unit/vagrant/config/loader_test.rb

@@ -17,6 +17,16 @@ describe Vagrant::Config::Loader do
     config.vagrant.dotfile_name.should == "foo"
   end
 
+  it "should only load configuration files once" do
+    $_config_data = 0
+
+    instance.load_order = [:file]
+    instance.set(:file, temporary_file("$_config_data += 1"))
+    5.times { instance.load }
+
+    $_config_data.should == 1
+  end
+
   it "should raise proper error if there is a syntax error in a Vagrantfile" do
     instance.load_order = [:file]
     instance.set(:file, temporary_file("Vagrant:^Config"))