Use config finalize to move some version-specific logic to the version

This moves out the concept of a "default VM" from the Environment class
and makes it the responsibility of the V1 configuration that at least
one VM is defined on it. This lets the configuration ultimately decide
what a "default" implementation is.

lib/vagrant/config/v1.rb

@@ -13,6 +13,17 @@ module Vagrant
         new_root_object
       end
 
+      # Finalizes the configuration by making sure there is at least
+      # one VM defined in it.
+      def self.finalize(config)
+        # Call the `#finalize` method on each of the configuration keys.
+        # They're expected to modify themselves in our case.
+        config.finalize!
+
+        # Return the object
+        config
+      end
+
       # Loads the configuration for the given proc and returns a configuration
       # object.
       #

lib/vagrant/config/v1/base.rb

@@ -5,6 +5,15 @@ module Vagrant
       # from this class but this class provides useful helpers that config
       # classes may wish to use.
       class Base
+        # This is called as a last-minute hook that allows the configuration
+        # object to finalize itself before it will be put into use. This is
+        # a useful place to do some defaults in the case the user didn't
+        # configure something or so on.
+        #
+        # The configuration object is expected to mutate itself.
+        def finalize!
+        end
+
         # Merge another configuration object into this one. This assumes that
         # the other object is the same class as this one.
         #

lib/vagrant/config/v1/root.rb

@@ -30,6 +30,15 @@ module Vagrant
           end
         end
 
+        # Called to finalize this object just prior to it being used by
+        # the Vagrant system. The "!" signifies that this is expected to
+        # mutate itself.
+        def finalize!
+          @keys.each do |_key, instance|
+            instance.finalize!
+          end
+        end
+
         # Validates the configuration classes of this instance and raises an
         # exception if they are invalid. If you are implementing a custom configuration
         # class, the method you want to implement is {Base#validate}. This is

lib/vagrant/config/version_base.rb

@@ -23,6 +23,10 @@ module Vagrant
       # This is an optional method to implement. The default implementation
       # will simply return the same object.
       #
+      # This will ONLY be called if this is the version that is being
+      # used. In the case that an `upgrade` is called, this will never
+      # be called.
+      #
       # @param [Object] obj Final configuration object.
       # @param [Object] Finalized configuration object.
       def self.finalize(obj)

lib/vagrant/environment.rb

@@ -13,7 +13,6 @@ module Vagrant
   # access to the VMs, CLI, etc. all in the scope of this environment.
   class Environment
     HOME_SUBDIRS = ["tmp", "boxes", "gems"]
-    DEFAULT_VM = :default
     DEFAULT_HOME = "~/.vagrant.d"
     DEFAULT_RC = "~/.vagrantrc"
 
@@ -163,7 +162,7 @@ module Vagrant
     #
     # @return [Bool]
     def multivm?
-      vms.length > 1 || vms.keys.first != DEFAULT_VM
+      vms.length > 1
     end
 
     # Makes a call to the CLI with the given arguments as if they
@@ -418,13 +417,6 @@ module Vagrant
       defined_vm_keys = global.vm.defined_vm_keys.dup
       defined_vms     = global.vm.defined_vms.dup
 
-      # If this isn't a multi-VM environment, then setup the default VM
-      # to simply be our configuration.
-      if defined_vm_keys.empty?
-        defined_vm_keys << DEFAULT_VM
-        defined_vms[DEFAULT_VM] = nil
-      end
-
       vm_configs = defined_vm_keys.map do |vm_name|
         @logger.debug("Loading configuration for VM: #{vm_name}")
 
@@ -434,11 +426,7 @@ module Vagrant
         config = inner_load[subvm]
 
         # Second pass, with the box
-        config = inner_load[subvm, boxes.find(config.vm.box)]
-        config.vm.name = vm_name
-
-        # Return the final configuration for this VM
-        config
+        inner_load[subvm, boxes.find(config.vm.box)]
       end
 
       # Finally, we have our configuration. Set it and forget it.

plugins/kernel_v1/config/vm.rb

@@ -8,6 +8,8 @@ require File.expand_path("../vm_subvm", __FILE__)
 module VagrantPlugins
   module Kernel_V1
     class VMConfig < Vagrant::Config::V1::Base
+      DEFAULT_VM_NAME = :default
+
       attr_accessor :name
       attr_accessor :auto_port_range
       attr_accessor :box
@@ -99,11 +101,25 @@ module VagrantPlugins
         defined_vm_keys << name
 
         # Add the SubVM to the hash of defined VMs
+        if !defined_vms[name]
+          # If it hasn't been defined before, then create the sub-VM configuration
+          # and configure it so that it has the proper name.
           defined_vms[name] ||= VagrantConfigSubVM.new
+          defined_vms[name].push_proc do |config|
+            config.vm.name = name
+          end
+        end
+
         defined_vms[name].options.merge!(options)
         defined_vms[name].push_proc(&block) if block
       end
 
+      def finalize!
+        # If we haven't defined a single VM, then we need to define a
+        # default VM which just inherits the rest of the configuration.
+        define(DEFAULT_VM_NAME) if defined_vm_keys.empty?
+      end
+
       def validate(env, errors)
         errors.add(I18n.t("vagrant.config.vm.box_missing")) if !box
         errors.add(I18n.t("vagrant.config.vm.box_not_found", :name => box)) if box && !box_url && !env.boxes.find(box)

test/unit/vagrant/config/v1_test.rb

@@ -10,6 +10,43 @@ describe Vagrant::Config::V1 do
     end
   end
 
+  describe "finalizing" do
+    it "should call `#finalize` on the configuration object" do
+      # Register a plugin for our test
+      plugin_class = Class.new(Vagrant.plugin("1")) do
+        name "test"
+        config "foo" do
+          Class.new do
+            attr_accessor :bar
+
+            def finalize!
+              @bar = "finalized"
+            end
+          end
+        end
+      end
+
+      # Create the proc we're testing
+      config_proc = Proc.new do |config|
+        config.foo.bar = "value"
+      end
+
+      begin
+        # Test that it works properly
+        config = described_class.load(config_proc)
+        config.foo.bar.should == "value"
+
+        # Finalize it
+        described_class.finalize(config)
+        config.foo.bar.should == "finalized"
+      ensure
+        # We have to unregister the plugin so that future tests
+        # aren't mucked up.
+        plugin_class.unregister!
+      end
+    end
+  end
+
   describe "loading" do
     it "should configure with all plugin config keys loaded" do
       # Register a plugin for our test