providers/virtualbox: detect conflict in name [GH-4681]

CHANGELOG.md

@@ -1,3 +1,10 @@
+## 1.7.0 (unreleased)
+
+BUG FIXES:
+
+  - providers/virtualbox: Show a human-friendly error if VirtualBox didn't
+      clean up an existing VM. [GH-4681]
+
 ## 1.6.5 (September 4, 2014)
 
 BUG FIXES:

lib/vagrant/errors.rb

@@ -728,6 +728,10 @@ module Vagrant
       error_key(:virtualbox_no_name)
     end
 
+    class VirtualBoxNameExists < VagrantError
+      error_key(:virtualbox_name_exists)
+    end
+
     class VMBaseMacNotSpecified < VagrantError
       error_key(:no_base_mac, "vagrant.actions.vm.match_mac")
     end

plugins/providers/virtualbox/driver/version_4_3.rb

@@ -475,6 +475,13 @@ module VagrantPlugins
 
         def set_name(name)
           execute("modifyvm", @uuid, "--name", name, retryable: true)
+        rescue Vagrant::Errors::VBoxManageError => e
+          raise if !e.extra_data[:stderr].include?("VERR_ALREADY_EXISTS")
+
+          # We got VERR_ALREADY_EXISTS. This means that we're renaming to
+          # a VM name that already exists. Raise a custom error.
+          raise Vagrant::Errors::VirtualBoxNameExists,
+            stderr: e.extra_data[:stderr]
         end
 
         def share_folders(folders)

templates/locales/en.yml

@@ -1193,6 +1193,18 @@ en:
         VirtualBox is complaining that the installation is incomplete. Please
         run `VBoxManage --version` to see the error message which should contain
         instructions on how to fix this error.
+      virtualbox_name_exists: |-
+        The name of your virtual machine couldn't be set because VirtualBox
+        is reporting another VM with that name already exists. Most of the
+        time, this is because of an error with VirtualBox not cleaning up
+        properly. To fix this, verify that no VMs with that name do exist
+        (by opening the VirtualBox GUI). If they don't, then look at the
+        folder in the error message from VirtualBox below and remove it
+        if there isn't any information you need in there.
+
+        VirtualBox error:
+
+        %{stderr}
       virtualbox_no_name: |-
         Vagrant was unable to determine the recommended name for your
         VirtualBox VM. This is usually an issue with VirtualBox. The output