Fiddle support?

[piotrmurach]

I've added TruffleRuby to tty-prompt gem travis configuration to see if it works with a more interesting project of mine. I hope to help you make the 1.0.0 relaese with this issue report. The tty-prompt ci fails due to lack of Fiddle::DLError which will probably be masking a real cause of the issue.

Does TruffleRuby provide support for fiddle anyway? Or does it handle native C calls differently?

[eregon]

Hello and thank you for the report!

We intend to support Fiddle, although currently our support is very minimal.
I'll try to take a look at what's needed to run tty-prompt.

What I see is that Fiddle is used for size_from_win_api in https://github.com/piotrmurach/tty-screen/blob/282ae528974059c16090212dbcfb4a3d5aa3bbeb/lib/tty/screen.rb#L80-L81
So probably just raising Fiddle::DLError when there is missing library is enough to go through that method (we don't support Windows currently).

[chrisseaton]

We worked a bit on Fiddle support in the past but paused when we realised we didn't really have any use-cases at the time. It's good to have a motivating user.

[eregon]

I have a fix for the usage of Fiddle in tty-screen going through CI.
It now works with both IO#ioctl, and also through io/console:

$ jt ruby -rtty-screen -e 'p TTY::Screen.size'
[72, 140]

[piotrmurach]

@eregon Ohh forgotten that tty-screen uses Fiddle as well. The actual dependency in tty-prompt is tty-reader that uses Fiddle to support Windows keyboard input on older systems(please see https://github.com/piotrmurach/tty-reader/blob/master/lib/tty/reader/win_api.rb)

@chrisseaton I thought this may be an interesting gem to try on travis due to Win API integration. I need to support this due to many Windows servers only supporting basic console.

[eregon]

@piotrmurach My fix for tty-screen got merged (e4211f0) and will be in the next release.
I'll try to run tty-prompt tests locally to see if there are other issues.

[eregon]

I ran the tty-prompt specs locally, and they all passed 😃

$ bundle exec rake ci
/home/eregon/code/truffleruby-ws/truffleruby/bin/truffleruby -I/home/eregon/code/truffleruby-ws/truffleruby/lib/ruby/gems/2.4.0/gems/rspec-core-3.8.0/lib:/home/eregon/code/truffleruby-ws/truffleruby/lib/ruby/gems/2.4.0/gems/rspec-support-3.8.0/lib /home/eregon/code/truffleruby-ws/truffleruby/lib/ruby/gems/2.4.0/gems/rspec-core-3.8.0/exe/rspec --pattern spec/\{unit,integration\}\{,/\*/\*\*\}/\*_spec.rb

Randomized with seed 28403
.................................................................................................................................................................................................................................................................................................................

Top 2 slowest examples (0.536 seconds, 14.0% of total time):
  TTY::Prompt::Question#keypress receives line feed with echo on
    0.38 seconds ./spec/unit/keypress_spec.rb:4
  TTY::Prompt::Question#keypress timeouts when no key provided
    0.156 seconds ./spec/unit/keypress_spec.rb:59

Top 2 slowest example groups:
  TTY::Prompt::Question#keypress
    0.1126 seconds average (0.563 seconds / 5 examples) ./spec/unit/keypress_spec.rb:3
  TTY::Prompt#collect
    0.0608 seconds average (0.304 seconds / 5 examples) ./spec/unit/collect_spec.rb:3

Finished in 3.82 seconds (files took 1.25 seconds to load)
305 examples, 0 failures

So I'll close this issue, and notify you when the next release is out.
Thank you again for the report.

[eregon]

BTW, I noticed tty-prompt depends on timers 4.1.2, which depends on hitimes.
hitimes works fine on Linux with TruffleRuby, but not yet on macOS (#1436).
More recent timers releases solve this problem by dropping the hitimes dependency and use Process.clock_gettime, but that also means Ruby >= 2.1 is required.

[piotrmurach]

@eregon Nice one! Thanks for the heads up. I use timers only for one of the prompts, I may consider dropping it altogether and roll my own solution for scheduling calling proc in equal intervals.