TypeError: can't convert Pathname into String - JRuby in 1.9 mode not handling Pathname in $LOAD_PATH consistently with MRI

$ rvm use jruby
Using lenny/.rvm/gems/jruby-1.6.4
$ ruby ./test.rb 
TypeError: can't convert Pathname into String
  require at org/jruby/RubyKernel.java:1047
  require at lenny/.rvm/rubies/jruby-1.6.4/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:29
   (root) at lenny/test.rb:3

$ rvm use 1.9.2
Using lenny/.rvm/gems/ruby-1.9.2-p290
bash-3.2$ ruby ./test.rb 
<internal:lib/rubygems/custom_require>:29:in `require': no such file to load -- foo (LoadError)
	from <internal:lib/rubygems/custom_require>:29:in `require'
	from lenny/test.rb:3:in `<main>'

src/org/jruby/runtime/load/LoadService.java" line 1169 (as of commit a8652d580 Thu Jan 26)
RubyString entryString = loadPath.eltInternal(i).convertToString();

In the case of a Pathname in the Loadpath it wound up invoking RubyBaseObject#convertToString

// org/jruby/RubyBasicObject.java
public RubyString convertToString() {
   return (RubyString) TypeConverter.convertToType(this, getRuntime().getString(), "to_str");
}

require 'pathname'

Pathname.class_eval do
  def to_str
    to_s
  end
end