Parse error when using jbuilder partials without an options hash

[RavenXce]

Steps to reproduce:

1. Call a partial with no options hash:

# new.json.jbuilder
json.foo do
  json.partial! 'foo/partial'
end

2. Render the jbuilder template

# foo controller
def new
  gon.jbuilder
end

Expected result:

The template is assigned to the JS gon.foo variable successfully.

Actual result:

Exception thrown: NoMethodError: undefined method '[]' for nil:NilClass Stacktrace:

21:29:06 web.1   |   gon (6.1.0) lib/gon/jbuilder/parser.rb:78:in `parse_partial'
21:29:06 web.1   |   gon (6.1.0) lib/gon/jbuilder/parser.rb:119:in `block in find_partials'
21:29:06 web.1   |   gon (6.1.0) lib/gon/jbuilder/parser.rb:117:in `find_partials'
21:29:06 web.1   |   gon (6.1.0) lib/gon/jbuilder/parser.rb:22:in `parse!'
21:29:06 web.1   |   gon (6.1.0) lib/gon/jbuilder.rb:18:in `handler'
21:29:06 web.1   |   gon (6.1.0) lib/gon.rb:96:in `jbuilder'
...

Notes:

It seems that line 78 of the parser tries to access the MatchData array even though String#match will return nil when there are no matches. The options_hash will therefore never be empty in a valid jbuilder template, meaning that the check is wrongly done.