core: scope hash override synced folder settings

lib/vagrant/action/builtin/synced_folders.rb

@@ -1,6 +1,7 @@
 require "log4r"
 
 require 'vagrant/util/platform'
+require 'vagrant/util/scoped_hash_override'
 
 module Vagrant
   module Action
@@ -8,6 +9,8 @@ module Vagrant
       # This middleware will setup the synced folders for the machine using
       # the appropriate synced folder plugin.
       class SyncedFolders
+        include Vagrant::Util::ScopedHashOverride
+
         def initialize(app, env)
           @app    = app
           @logger = Log4r::Logger.new("vagrant::action::builtin::synced_folders")
@@ -16,18 +19,21 @@ module Vagrant
         def call(env)
           folders = synced_folders(env[:machine])
 
-          # Log all the folders that we have enabled and with what
-          # implementation...
-          folders.each do |impl, fs|
-            @logger.info("Synced Folder Implementation: #{impl}")
+          folders.each do |impl_name, fs|
+            @logger.info("Synced Folder Implementation: #{impl_name}")
+
             fs.each do |id, data|
+              # Log every implementation and their paths
               @logger.info("  - #{id}: #{data[:hostpath]} => #{data[:guestpath]}")
+
+              # Scope hash override
+              fs[id] = scoped_hash_override(data, impl_name)
             end
           end
 
           # Go through each folder and make sure to create it if
           # it does not exist on host
-          folders.each do |impl, fs|
+          folders.each do |_, fs|
             fs.each do |id, data|
               data[:hostpath] = File.expand_path(data[:hostpath], env[:root_path])
 

test/unit/vagrant/action/builtin/synced_folders_test.rb

@@ -101,6 +101,28 @@ describe Vagrant::Action::Builtin::SyncedFolders do
 
       order.should == [:prepare, :enable]
     end
+
+    it "should scope hash override the settings" do
+      actual = nil
+      tracker = Class.new(impl(true, "good")) do
+        define_method(:prepare) do |machine, folders, opts|
+          actual = folders
+        end
+      end
+
+      plugins[:tracker] = [tracker, 15]
+
+      synced_folders["tracker"] = {
+        "root" => {
+          hostpath: "foo",
+          tracker__foo: "bar",
+        },
+      }
+
+      subject.call(env)
+
+      actual["root"][:foo].should == "bar"
+    end
   end
 
   describe "default_synced_folder_type" do