In a multi-machine environment, don't download box multiple [GH-1467]

CHANGELOG.md

@@ -15,6 +15,8 @@ BUG FIXES:
   - `vagrant package --base` works again. [GH-1615]
   - Box overrides specified in provider config overrides no longer
     fail to detect the box. [GH-1617]
+  - In a multi-machine environment, a box not found won't be downloaded
+    multiple times. [GH-1467]
 
 ## 1.2.1 (April 17, 2013)
 

lib/vagrant/action/builtin/handle_box_url.rb

@@ -24,11 +24,17 @@ module Vagrant
               "vagrant.actions.vm.check_box.not_found",
               :name => box_name,
               :provider => env[:machine].provider_name)
-            env[:action_runner].run(Vagrant::Action.action_box_add, {
-              :box_name     => box_name,
-              :box_provider => env[:machine].provider_name,
-              :box_url      => box_url
-            })
+
+            begin
+              env[:action_runner].run(Vagrant::Action.action_box_add, {
+                :box_name     => box_name,
+                :box_provider => env[:machine].provider_name,
+                :box_url      => box_url
+              })
+            rescue Errors::BoxAlreadyExists
+              # Just ignore this, since it means the next part will succeed!
+              # This can happen in a multi-threaded environment.
+            end
 
             # Reload the environment and set the VM to be the new loaded VM.
             env[:machine] = env[:machine].env.machine(