[TxMt] Re: TextMate 1.5 and Ruby 2.0.0

[Matt Neuburg]

Allan Odgaard <mailinglist at textmate.org>
wrote:

> On Mar 6, 2013, at 20:21, Matt Neuburg
> <matt at tidbits.com> wrote:
> 
> > Ruby 2.0.0 is causing further trouble, on this line:
> > 
> >    io = IO.for_fd(ENV['TM_ERROR_FD'].to_i)
> > 
> > This generates "Bad file descriptor".
> 
> What about this:
> 
>     IO.for_fd(2) << "test\n"
> 
> Does that work?
> 
> If it works, try this code as well:
> 
>     rd, wr = IO.pipe
>     fork do
>       io = IO.for_fd(wr.to_i)
>       io << "test\n"
>       io.close
>     end
>     puts rd.gets
> 
> >  don't know how TM_ERROR_FD is set or what might be wrong with it
> >  as a file descriptor (it's just a number).
> 
> It is setup by TextMate.executor and the number is the file descriptor
> which is the write-end of a pipe created.

Very cool, thanks! The problem is that that doesn't fit in with
RubyMate's way of processing the error message. We are in
SharedSupport/Bundles/Ruby.tmbundle/Support/RubyMate/catch_exception.rb.
Here, the error message is parsed and is wrapped in some HTML before
being fed into the IO object whose number comes from TM_ERROR_FD. That
IO object is evidently piped into TextMate's output window, where it
appears formatted. If we feed the HTML to just any old IO (such as 2),
it isn't formatted; it appears as raw HTML in the output window.

It's odd, isn't it? What could there possibly be about Ruby 2.0.0 that
would make the int value of TM_ERROR_FD a "bad file descriptor" when it
is a perfectly good file descriptor under previous versions of Ruby?

I tried just running this script as a way of seeing what file
descriptors are good and what file descriptors are bad:

(-200..200).each do |n|
  begin
    IO.for_fd(n) << "#{n} test\n"
    puts "#{n} succeeded"
  rescue
    puts "#{n} failed"
  end
end

Only 1 and 2 are good. But TM_ERROR_FD is 9 (though that particular
number is just an implementation detail on any given run).

Mysterious, eh?

By the way, I see now that this same question has been asked before:

http://lists.macromates.com/textmate/2012-April/034878.html

m.


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matt neuburg, phd = matt at tidbits.com, http://www.apeth.net/matt/
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