Fix crashing bug if .vagrant is invalid. [closes GH-496]

CHANGELOG.md

@@ -1,6 +1,7 @@
 ## 0.8.7 (unreleased)
 
   - Fix regression with remote paths from chef-solo. [GH-431]
+  - Fix issue where Vagrant crashes if `.vagrant` file becomes invalid. [GH-496]
 
 ## 0.8.6 (August 28, 2011)
 

lib/vagrant/data_store.rb

@@ -23,7 +23,12 @@ module Vagrant
 
       if File.exist?(file_path)
         File.open(file_path, "r") do |f|
+          begin
             merge!(JSON.parse(f.read))
+          rescue JSON::ParserError
+            # Ignore if the data is invalid in the file.
+            # TODO: Log here.
+          end
         end
       end
     end

test/unit/vagrant/data_store_test.rb

@@ -23,6 +23,14 @@ class DataStoreTest < Test::Unit::TestCase
     }
   end
 
+  should "initialize just fine if the db file contains invalid data" do
+    file = tmp_path.join("data_store_empty_test")
+    File.open(file, "w") { |f| f.write("") }
+
+    instance = @klass.new(file)
+    assert instance.length == 0
+  end
+
   should "be a hash with indifferent access" do
     assert @instance.is_a?(Vagrant::Util::HashWithIndifferentAccess)
   end