reported ThreadContext file/line do not match (MRI)

[kares]

while implementing (and trying to test) some Thread#name propagating into the Java thread name, I noticed reported file/line get a little wild on JRuby - e.g. test/unit messes them up (although even without the require 'test/unit' the line number is not correct) :

require 'test/unit'

@@inspect = nil

Thread.new do
  @@inspect = Thread.current.inspect
  if defined? JRUBY_VERSION
    @@inspect += ' ' + Thread.current.to_java.native_thread.name
  end
end.join

puts @@inspect

# MRI:
#   #<Thread:0x00000001c9f968@thread_location.rb:5 run>
# JRuby 1.7.22: with commented-out # require 'test/unit' :
#   #<Thread:0x6b281ec1 run> Ruby-0-Thread-2: thread_location.rb:3
# JRuby 9.0.4.0: with commented-out # require 'test/unit' :
#   #<Thread:0x11bdb67e run> Ruby-0-Thread-1: thread_location.rb:3
# JRuby 9.0.4.0: as is - uncommented require 'test/unit' :
#   #<Thread:0x23ab7871 run> Ruby-0-Thread-3: thread_location.rb:1
# JRuby 9K (ruby-2.3) as is - uncommented require 'test/unit' :
#   #<Thread:0x5c92a526@thread_location.rb:1 run> Ruby-0-Thread-1: thread_location.rb:1

class TestTest < Test::Unit::TestCase

  @@inspect = nil

  def test_thread
    Thread.new do
      @@inspect = Thread.current.inspect
        if defined? JRUBY_VERSION
          @@inspect += ' ' + Thread.current.to_java.native_thread.name
        end
    end.join
    puts @@inspect
  end

end

# MRI 2.2.3/2.3.0:
#   #<Thread:0x00000002146598@thread_location.rb:30 run>
# JRuby 9.0.4.0 / 9K (ruby-2.3):
#   #<Thread:0x2de0b137 run> Ruby-0-Thread-4: /opt/local/rvm/rubies/jruby-9.0.4.0/lib/ruby/stdlib/test/unit/testcase.rb:697
#   #<Thread:0x11911e61@/home/kares/workspace/oss/jruby/lib/ruby/stdlib/test/unit/testcase.rb:697 run> Ruby-0-Thread-2: /home/kares/workspace/oss/jruby/lib/ruby/stdlib/test/unit/testcase.rb:697

recall this is smt I've run into in the past as well ... Thread.new sometimes not having a correct line number when looking through VisualVM - although that is not that relevant, since it wasn't much visible. nowdays (since Ruby 2.2) Thread#inspect includes the Thread.new source location so it would be great to have it right.

p.s. also context.getFile gets "" (empty) and context.getLine == 0 when JIT-ed