Puppet

If you write a type that looks like this:

Puppet::Type.newtype(:foo) do

  ensurable do
    defaultvalues
    defaultto :present
  end
end

And you then try to instantiate it using something like:

resource = Puppet::Type::Foo.new(:title => 'myfoo')

You will get a very bad error message about Array not having a method called “merge” or something to that effect. This is because in lib/puppet/type.rb around line 225 we have:

 
def self.title_patterns
    case key_attributes.length
    when 0; []
    when 1;
...

Which returns an empty array if there is no namevar, and then in lib/puppet/resource.rb around line 423:

def parse_title
    h = {}
    type = resource_type
    if type.respond_to? :title_patterns
      type.title_patterns.each { |regexp, symbols_and_lambdas|
        if captures = regexp.match(title.to_s)
          symbols_and_lambdas.zip(captures[1..-1]).each { |symbol_and_lambda,capture|
            sym, lam = symbol_and_lambda
            #self[sym] = lam.call(capture)
            h[sym] = lam.call(capture)
          }
          return h
        end
      }
    else
      return { :name => title.to_s }
    end
  end

Basically this method falls through and unintentionally returns that empty array in that case… which leads to a very bad error message. I would have submitted a fix but I’m not sure what the desired behavior is; I suspect it’s that we should give a clear error message about there being no namevar, but if so, I’m not sure whether that should happen in type.rb or resource.rb.