core: re-ask if confirmation bad input [GH-3027]

CHANGELOG.md

@@ -37,6 +37,7 @@ IMPROVEMENTS:
 
   - core: Added "error-exit" type to machine-readable output which contains
     error information that caused a non-zero exit status. [GH-2999]
+  - command/destroy: confirmation will re-ask question if bad input. [GH-3027]
   - guests/solaris: More accurate Solaris >= 11, < 11 detection. [GH-2824]
   - provisioners/chef-solo: New config `synced_folder_type` replaces the
     `nfs` option. This can be used to set the synced folders the provisioner

lib/vagrant/action/builtin/confirm.rb

@@ -11,10 +11,11 @@ module Vagrant
         # @param [String] message The message to ask the user.
         # @param [Symbol] force_key The key that if present and true in
         #   the environment hash will skip the confirmation question.
-        def initialize(app, env, message, force_key=nil)
+        def initialize(app, env, message, force_key=nil, **opts)
           @app      = app
           @message  = message
           @force_key = force_key
+          @allowed  = opts[:allowed]
         end
 
         def call(env)
@@ -24,8 +25,16 @@ module Vagrant
           # the result to "Y"
           choice = "Y" if @force_key && env[@force_key]
 
-          # If we haven't chosen yes, then ask the user via TTY
+          if !choice
-          choice = env[:ui].ask(@message) if !choice
+            while true
+              # If we haven't chosen yes, then ask the user via TTY
+              choice = env[:ui].ask(@message)
+
+              # If we don't have an allowed set just exit
+              break if !@allowed
+              break if @allowed.include?(choice)
+            end
+          end
 
           # The result is only true if the user said "Y"
           env[:result] = choice && choice.upcase == "Y"

lib/vagrant/action/builtin/destroy_confirm.rb

@@ -13,7 +13,7 @@ module Vagrant
           message   = I18n.t("vagrant.commands.destroy.confirmation",
                              :name => env[:machine].name)
 
-          super(app, env, message, force_key)
+          super(app, env, message, force_key, allowed: ["y", "n", "Y", "N"])
         end
       end
     end

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

@@ -33,4 +33,21 @@ describe Vagrant::Action::Builtin::Confirm do
     described_class.new(app, env, message).call(env)
     env[:result].should_not be
   end
+
+  it "should ask multiple times if an allowed set is given and response isn't in that set" do
+    times = 0
+    env[:ui].stub(:ask) do |arg|
+      expect(arg).to eql(message)
+      times += 1
+
+      if times <= 3
+        "nope"
+      else
+        "y"
+      end
+    end
+    described_class.new(app, env, message, allowed: ["y", "N"]).call(env)
+    expect(env[:result]).to be_true
+    expect(times).to eq(4)
+  end
 end