pty is missing in the standard library

[deepj]

See https://ruby-doc.org/stdlib-2.0.0/libdoc/pty/rdoc/PTY.html

To reproduce:

require 'pty'

Error:

LoadError: cannot load such file -- pty
	from ~/.rubies/truffleruby-1.0.0-rc12/lib/mri/rubygems/core_ext/kernel_require.rb:55:in `gem_original_require'
	from ~/.rubies/truffleruby-1.0.0-rc12/lib/mri/rubygems/core_ext/kernel_require.rb:55:in `require'
	from (irb):1
	from ~/.rubies/truffleruby-1.0.0-rc12/bin/irb:29:in `<main>'

This gem is used in querly tests

[chrisseaton]

I'm just working on updating our documentation on standard libraries.

Standard libraries

The following standard libraries are unsupported.

• continuation
• dbm
• gdbm
• sdbm
• io/console (partially implemented, could be implemented in the future)
• io/nonblock (could be implemented in the future)
• io/wait (partially implemented, could be implemented in the future)
• pty (could be implemented in the future)
• ripper (could be implemented in the future)
• win32
• win32ole

fiddle is not yet implemented - the module and some methods are there
but not enough to run anything serious.

We provide our own included implementation of the interface of the ffi gem,
like JRuby and Rubinius, but the implemention of this is limited at the
moment.

EDIT: See https://github.com/oracle/truffleruby/blob/master/doc/user/compatibility.md#standard-libraries for up-to-date info.

[eregon]

pty is used by the tests of the debug gem:
https://github.com/ruby/debug/blob/d0a3372a864d3906ac2a81907b9222dba15883be/test/support/utils.rb#L3

It would be worth trying if importing the pty sources from CRuby works.

[eregon]

@bjfish Could you try that?

[matthewford]

also causes an issue with the appsignal apm

[matthewford]

wicked_pdf gem also use pty

[chrisseaton]

I have a PR partially done to add pty - will take a look at it again. It's also needed to run the debug gem tests.

[eregon]

JRuby recently used libfixposix to get pty working in jruby/jruby#6552, possibly relevant for us, as from reading that issue posix_spawn doesn't have that ability. But we could probably also do it in https://github.com/oracle/truffleruby/blob/master/src/main/c/spawn-helper/spawn-helper.c and that would be simpler/more direct.

[eregon]

As a note, using the pty extension won't work because that relies on fork()