Force command to be re-run after installing local plugins

Reloading the Vagrantfile causes issue with multiple evaluations
where users expect single evaluation. Instead of allowing local
plugin installation to happen prior to command execution, force
halt after installation and the command to be re-run. This will
prevent multiple loads of the Vagrantfile within a single run.

lib/vagrant/environment.rb

@@ -167,21 +167,18 @@ module Vagrant
 
       # Initialize localized plugins
       plugins = Vagrant::Plugin::Manager.instance.localize!(self)
+      # Load any environment local plugins
+      Vagrant::Plugin::Manager.instance.load_plugins(plugins)
+
+      # Initialize globalize plugins
+      plugins = Vagrant::Plugin::Manager.instance.globalize!
+      # Load any global plugins
+      Vagrant::Plugin::Manager.instance.load_plugins(plugins)
 
       if !vagrantfile.config.vagrant.plugins.empty?
         plugins = process_configured_plugins
       end
 
-      # Load any environment local plugins
-      Vagrant::Plugin::Manager.instance.load_plugins(plugins)
-
-      plugins = Vagrant::Plugin::Manager.instance.globalize!
-      Vagrant::Plugin::Manager.instance.load_plugins(plugins)
-
-      # Reset so Vagrantfile will be reloaded with expected support for
-      # any new plugins provided
-      post_plugins_reset!
-
       # Call the hooks that does not require configurations to be loaded
       # by using a "clean" action runner
       hook(:environment_plugins_loaded, runner: Action::Runner.new(env: self))
@@ -917,18 +914,6 @@ module Vagrant
 
     protected
 
-    # Unsets the internal vagrantfile and config_loader
-    # to force them to be regenerated. This is used after
-    # plugins have been loaded so that newly discovered
-    # plugin configurations are properly available
-    #
-    # @return [nil]
-    def post_plugins_reset!
-      @vagrantfile = nil
-      @config_loader = nil
-      nil
-    end
-
     # Check for any local plugins defined within the Vagrantfile. If
     # found, validate they are available. If they are not available,
     # request to install them, or raise an exception
@@ -982,7 +967,10 @@ module Vagrant
             name: spec.name, version: spec.version.to_s))
         end
         ui.info("\n")
-        Vagrant::Plugin::Manager.instance.localize!(self)
+        # Force halt after installation and require command to be run again. This
+        # will proper load any new locally installed plugins which are now available.
+        ui.warn(I18n.t("vagrant.plugins.local.install_rerun_command"))
+        exit(-1)
       end
       Vagrant::Plugin::Manager.instance.local_file.installed_plugins
     end

templates/locales/en.yml

@@ -419,6 +419,9 @@ en:
             %{plugins}
         request_plugin_install: |-
           Install local plugins (Y/N)
+        install_rerun_command: |-
+          Vagrant has completed installing local plugins for the current Vagrant
+          project directory. Please run the requested command again.
 
         install_all: |-
           Vagrant will now install the following plugins to the local project

test/unit/vagrant/environment_test.rb

@@ -25,13 +25,6 @@ describe Vagrant::Environment do
   let(:instance)  { env.create_vagrant_env }
   subject { instance }
 
-  describe "#initialize" do
-    it "should do an internal reset after plugin loading" do
-      expect_any_instance_of(described_class).to receive(:post_plugins_reset!)
-      instance
-    end
-  end
-
   describe "#can_install_provider?" do
     let(:plugin_hosts) { {} }
     let(:plugin_host_caps) { {} }
@@ -1495,6 +1488,8 @@ VF
 
       context "without plugin installed" do
 
+        before { allow(instance).to receive(:exit) }
+
         it "should prompt user before installation" do
           expect(instance.ui).to receive(:ask).and_return("n")
           expect(plugin_manager).to receive(:installed_plugins).and_return({})
@@ -1507,6 +1502,14 @@ VF
           expect(plugin_manager).to receive(:install_plugin).and_return(double("spec", "name" => "vagrant", "version" => "1"))
           instance.send(:process_configured_plugins)
         end
+
+        it "should exit after install" do
+          expect(instance.ui).to receive(:ask).and_return("y")
+          expect(plugin_manager).to receive(:installed_plugins).and_return({})
+          expect(plugin_manager).to receive(:install_plugin).and_return(double("spec", "name" => "vagrant", "version" => "1"))
+          expect(instance).to receive(:exit)
+          instance.send(:process_configured_plugins)
+        end
       end
     end
   end