From ab70dc271bc4188898b9cd4ad29156e705514678 Mon Sep 17 00:00:00 2001
From: Mitchell Hashimoto <mitchell.hashimoto@gmail.com>
Date: Sat, 23 Nov 2013 10:47:06 -0800
Subject: [PATCH] core: verify explicit sf types are usable

---
 lib/vagrant/action/builtin/synced_folders.rb    | 17 +++++++++++++----
 lib/vagrant/errors.rb                           |  4 ++++
 templates/locales/en.yml                        |  4 ++++
 .../action/builtin/synced_folders_test.rb       |  8 ++++++++
 4 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/lib/vagrant/action/builtin/synced_folders.rb b/lib/vagrant/action/builtin/synced_folders.rb
index 4daba7a28..0d0eb9356 100644
--- a/lib/vagrant/action/builtin/synced_folders.rb
+++ b/lib/vagrant/action/builtin/synced_folders.rb
@@ -124,10 +124,19 @@ module Vagrant
             impl = ""
             impl = data[:type].to_sym if data[:type]
 
-            if impl != "" && !plugins[impl]
-              # This should never happen because configuration validation
-              # should catch this case. But we put this here as an assert
-              raise "Internal error. Report this as a bug. Invalid: #{data[:type]}"
+            if impl != ""
+              impl_class = plugins[impl]
+              if !impl_class
+                # This should never happen because configuration validation
+                # should catch this case. But we put this here as an assert
+                raise "Internal error. Report this as a bug. Invalid: #{data[:type]}"
+              end
+
+              if !impl_class[0].new.usable?(machine)
+                # Verify that explicitly defined shared folder types are
+                # actually usable.
+                raise Errors::SyncedFolderUnusable, type: data[:type].to_s
+              end
             end
 
             # Keep track of this shared folder by the implementation.
diff --git a/lib/vagrant/errors.rb b/lib/vagrant/errors.rb
index 625637883..6a8cd7466 100644
--- a/lib/vagrant/errors.rb
+++ b/lib/vagrant/errors.rb
@@ -512,6 +512,10 @@ module Vagrant
       error_key(:ssh_unavailable_windows)
     end
 
+    class SyncedFolderUnusable < VagrantError
+      error_key(:synced_folder_unusable)
+    end
+
     class UIExpectsTTY < VagrantError
       error_key(:ui_expects_tty)
     end
diff --git a/templates/locales/en.yml b/templates/locales/en.yml
index 5999ec4ba..114f53913 100644
--- a/templates/locales/en.yml
+++ b/templates/locales/en.yml
@@ -580,6 +580,10 @@ en:
         Port: %{port}
         Username: %{username}
         Private key: %{key_path}
+      synced_folder_unusable: |=
+        The synced folder type '%{type}' is reporting as unusable for
+        your current setup. Please verify you have all the proper
+        prerequisites for using this shared folder type and try again.
       test_key: "test value"
       ui_expects_tty: |-
         Vagrant is attempting to interface with the UI in a way that requires
diff --git a/test/unit/vagrant/action/builtin/synced_folders_test.rb b/test/unit/vagrant/action/builtin/synced_folders_test.rb
index ae7faddfc..2cb123096 100644
--- a/test/unit/vagrant/action/builtin/synced_folders_test.rb
+++ b/test/unit/vagrant/action/builtin/synced_folders_test.rb
@@ -160,6 +160,14 @@ describe Vagrant::Action::Builtin::SyncedFolders do
       result[:nfs].should == { "nfs" => folders["nfs"] }
     end
 
+    it "should error if an explicit type is unusable" do
+      plugins[:unusable] = [impl(false, "bad"), 15]
+      folders["root"] = { type: "unusable" }
+
+      expect { subject.synced_folders(machine) }.
+        to raise_error
+    end
+
     it "should ignore disabled folders" do
       folders["root"] = {}
       folders["foo"] = { disabled: true }