Show nice error if vagrant destroy can't confirm [GH-779]

CHANGELOG.md

@@ -2,6 +2,8 @@
 
   - Add missing `rubygems` require in `environment.rb` to avoid
     possible load errors. [GH-781]
+  - `vagrant destroy` shows a nice error when called without a
+    TTY (and hence can't confirm). [GH-779]
 
 ## 1.0.0 (March 6, 2012)
 

lib/vagrant/command/destroy.rb

@@ -30,8 +30,15 @@ module Vagrant
             if options[:force]
               do_destroy = true
             else
-              choice = @env.ui.ask(I18n.t("vagrant.commands.destroy.confirmation",
+              choice = nil
-                                          :name => vm.name))
+              begin
+                choice = @env.ui.ask(I18n.t("vagrant.commands.destroy.confirmation",
+                                            :name => vm.name))
+              rescue Errors::UIExpectsTTY
+                # We raise a more specific error but one which basically
+                # means the same thing.
+                raise Errors::DestroyRequiresForce
+              end
               do_destroy = choice.upcase == "Y"
             end
 

lib/vagrant/errors.rb

@@ -148,6 +148,11 @@ module Vagrant
       error_key(:deprecation)
     end
 
+    class DestroyRequiresForce < VagrantError
+      status_code(74)
+      error_key(:destroy_requires_force)
+    end
+
     class DotfileIsDirectory < VagrantError
       status_code(46)
       error_key(:dotfile_is_directory)

templates/locales/en.yml

@@ -36,6 +36,10 @@ en:
 
         %{message}
         Note that this error message will not appear in the next version of Vagrant.
+      destroy_requires_force: |-
+        Destroy doesn't have a TTY to ask for confirmation. Please pass the
+        `--force` flag to force a destroy, otherwise attach a TTY so that
+        the destroy can be confirmed.
       dotfile_is_directory: |-
         The local file Vagrant uses to store data ".vagrant" already exists
         and is a directory! If you are in your home directory, then please run