core: load system plugins if they are installed

lib/vagrant.rb

@@ -125,14 +125,6 @@ module Vagrant
     c.register([:"2", :synced_folder]) { Plugin::V2::SyncedFolder }
   end
 
-  # This returns a true/false showing whether we're running from the
-  # environment setup by the Vagrant installers.
-  #
-  # @return [Boolean]
-  def self.in_installer?
-    !!ENV["VAGRANT_INSTALLER_ENV"]
-  end
-
   # Configure a Vagrant environment. The version specifies the version
   # of the configuration that is expected by the block. The block, based
   # on that version, configures the environment.

lib/vagrant/plugin/manager.rb

@@ -1,3 +1,4 @@
+require "pathname"
 require "set"
 
 require_relative "../bundler"
@@ -8,20 +9,31 @@ module Vagrant
   module Plugin
     # The Manager helps with installing, listing, and initializing plugins.
     class Manager
-      # Returns the path to the [StateFile] for global plugins.
+      # Returns the path to the [StateFile] for user plugins.
       #
       # @return [Pathname]
-      def self.global_plugins_file
+      def self.user_plugins_file
         Vagrant.user_data_path.join("plugins.json")
       end
 
-      def self.instance
-        @instance ||= self.new(global_plugins_file)
+      # Returns the path to the [StateFile] for system plugins.
+      def self.system_plugins_file
+        dir = Vagrant.installer_embedded_dir
+        return nil if !dir
+        Pathname.new(dir).join("plugins.json")
       end
 
-      # @param [Pathname] global_file
-      def initialize(global_file)
-        @global_file = StateFile.new(global_file)
+      def self.instance
+        @instance ||= self.new(user_plugins_file)
+      end
+
+      # @param [Pathname] user_file
+      def initialize(user_file)
+        @user_file   = StateFile.new(user_file)
+
+        system_path  = self.class.system_plugins_file
+        @system_file = nil
+        @system_file = StateFile.new(system_path) if system_path && system_path.file?
       end
 
       # Installs another plugin into our gem directory.
@@ -65,7 +77,7 @@ module Vagrant
         opts.delete(:version) if opts[:version] && opts[:version] =~ /^\d/
 
         # Add the plugin to the state file
-        @global_file.add_plugin(
+        @user_file.add_plugin(
           result.name,
           version: opts[:version],
           require: opts[:require],
@@ -83,7 +95,7 @@ module Vagrant
       #
       # @param [String] name
       def uninstall_plugin(name)
-        @global_file.remove_plugin(name)
+        @user_file.remove_plugin(name)
 
         # Clean the environment, removing any old plugins
         Vagrant::Bundler.instance.clean(installed_plugins)
@@ -102,7 +114,8 @@ module Vagrant
       #
       # @return [Hash]
       def installed_plugins
-        @global_file.installed_plugins
+        system = @system_file ? @system_file.installed_plugins : {}
+        system.merge(@user_file.installed_plugins)
       end
 
       # This returns the list of plugins that are installed as

lib/vagrant/plugin/state_file.rb

@@ -57,6 +57,13 @@ module Vagrant
         @data["installed"]
       end
 
+      # Returns true/false if the plugin is present in this state file.
+      #
+      # @return [Boolean]
+      def has_plugin?(name)
+        @data["installed"].has_key?(name)
+      end
+
       # Remove a plugin that is installed from the state file.
       #
       # @param [String] name The name of the plugin.

lib/vagrant/shared_helpers.rb

@@ -8,6 +8,14 @@ module Vagrant
   # @return [String]
   DEFAULT_SERVER_URL = "https://www.vagrantcloud.com"
 
+  # This returns a true/false showing whether we're running from the
+  # environment setup by the Vagrant installers.
+  #
+  # @return [Boolean]
+  def self.in_installer?
+    !!ENV["VAGRANT_INSTALLER_ENV"]
+  end
+
   # Returns the path to the embedded directory of the Vagrant installer,
   # if there is one (if we're running in an installer).
   #

test/unit/vagrant/plugin/state_file_test.rb

@@ -38,6 +38,12 @@ describe Vagrant::Plugin::StateFile do
       })
     end
 
+    it "should check for plugins" do
+      expect(subject.has_plugin?("foo")).to be_false
+      subject.add_plugin("foo")
+      expect(subject.has_plugin?("foo")).to be_true
+    end
+
     it "should remove plugins" do
       subject.add_plugin("foo")
       subject.remove_plugin("foo")

test/unit/vagrant/shared_helpers_test.rb

@@ -8,6 +8,20 @@ describe Vagrant do
 
   subject { described_class }
 
+  describe "#in_installer?" do
+    it "is not if env is not set" do
+      with_temp_env("VAGRANT_INSTALLER_ENV" => nil) do
+        expect(subject.in_installer?).to be_false
+      end
+    end
+
+    it "is if env is set" do
+      with_temp_env("VAGRANT_INSTALLER_ENV" => "/foo") do
+        expect(subject.in_installer?).to be_true
+      end
+    end
+  end
+
   describe "#installer_embedded_dir" do
     it "returns nil if not in an installer" do
       Vagrant.stub(in_installer?: false)