Give a nice error message if there is a syntax error in Vagrantfile [closes GH-154]

CHANGELOG.md

@@ -1,5 +1,7 @@
 ## 0.6.0 (unreleased)
 
+  - Vagrant now gives a nice error message if there is a syntax error
+    in any Vagrantfile. [GH-154]
   - The format of the ".vagrant" file which stores persisted VMs has
     changed. This is **backwards incompatible**. Will provide an upgrade
     utility prior to 0.6 launch.

bin/vagrant

@@ -9,7 +9,7 @@ begin
 rescue Vagrant::Errors::VagrantError => e
   opts = { :_translate => false, :_prefix => false }
   env.ui.error e.message, opts if e.message
-  env.ui.error e.backtrace.join("\n"), opts if ENV["VAGRANT_DEBUG"]
+  env.ui.error e.backtrace.join("\n"), opts if ENV["VAGRANT_DEBUG"] || e.show_stacktrace
   exit e.status_code if e.respond_to?(:status_code)
   exit 999 # An error occurred with no status code defined
 end

lib/vagrant/config.rb

@@ -52,7 +52,12 @@ module Vagrant
 
       queue.flatten.each do |item|
         if item.is_a?(String) && File.exist?(item)
-          load item
+          begin
+            load item
+          rescue SyntaxError
+            # Report syntax errors in a nice way for Vagrantfiles
+            raise Errors::VagrantfileSyntaxError.new(:file => item)
+          end
         elsif item.is_a?(Proc)
           self.class.run(&item)
         end

lib/vagrant/errors.rb

@@ -29,6 +29,10 @@ module Vagrant
         define_method(:error_namespace) { namespace }
       end
 
+      def self.force_stacktrace
+        define_method(:show_stacktrace) { true }
+      end
+
       def initialize(message=nil, *args)
         message = { :_key => message } if message && !message.is_a?(Hash)
         message = { :_key => error_key, :_namespace => error_namespace }.merge(message || {})
@@ -46,6 +50,9 @@ module Vagrant
       # {error_key} method but can be overridden here if needed.
       def error_key; nil; end
 
+      # Force the stacktrace to show (false by default)
+      def show_stacktrace; false; end
+
       protected
 
       def translate_error(opts)
@@ -209,6 +216,12 @@ module Vagrant
       error_key(:interrupted)
     end
 
+    class VagrantfileSyntaxError < VagrantError
+      status_code(41)
+      error_key(:vagrantfile_syntax_error)
+      force_stacktrace
+    end
+
     class VirtualBoxInvalidOSE < VagrantError
       status_code(9)
       error_key(:virtualbox_invalid_ose)

templates/locales/en.yml

@@ -56,6 +56,11 @@ en:
         unspecified: |-
           A VM system type must be specified! This is done via the `config.vm.system`
           configuration value. Please read the documentation online for more information.
+      vagrantfile_syntax_error: |-
+        There is a syntax error in the following Vagrantfile. The stack trace
+        is also printed below for convenience.
+
+        %{file}
       virtualbox_invalid_ose: |-
         Vagrant has detected you're using an OSE ("Open Source Edition") of VirtualBox.
         Vagrant currently doesn't support any of the OSE editions due to slight API

test/vagrant/config_test.rb

@@ -57,6 +57,16 @@ class ConfigTest < Test::Unit::TestCase
       @instance.queue << filename
       @instance.load!
     end
+
+    should "raise an exception if there is a syntax error in a file" do
+      @instance.queue << "foo"
+      File.expects(:exist?).with("foo").returns(true)
+      @instance.expects(:load).with("foo").raises(SyntaxError.new)
+
+      assert_raises(Vagrant::Errors::VagrantfileSyntaxError) {
+        @instance.load!
+      }
+    end
   end
 
   context "adding configures" do

test/vagrant/errors_test.rb

@@ -39,4 +39,13 @@ class ErrorsTest < Test::Unit::TestCase
     klass = Class.new(@super) { error_key(:test_key_with_interpolation) }
     assert_equal I18n.t("vagrant.test.errors.test_key_with_interpolation", :key => "yo"), klass.new(:key => "yo").message
   end
+
+  should "not force stacktrace show by default" do
+    assert !@super.new.show_stacktrace
+  end
+
+  should "force stacktrace to show if enabled" do
+    klass = Class.new(@super) { force_stacktrace }
+    assert klass.new.show_stacktrace
+  end
 end