Suspend not working in IRB Ruby 3.1.2

[sandro]

Description

When I enter IRB session, I expect pressing CTRL-Z to suspend the program, but it does not. If I press <Enter> after CTRL-Z I see irb(main):002:0* ^Z

Suspend functionality works fine for me on Ruby 2.7 and Ruby 3.0.1

Terminal Emulator

What's your terminal emulator?

ZSH
iTerm2 and Terminal on Mac OS

[junaruga]

What's your terminal emulator?

ZSH

I suppose that the "ZSH" is not the terminal emulator but the shell. The terminal emulator is like "terminator", "alacrity", "xterm" and etc. See https://en.wikipedia.org/wiki/List_of_terminal_emulators.

[sandro]

@junaruga my mistake, I use iTerm2 but Terminal on Mac OS is also affected.

[elfham]

It looks like that bug got in at #335.

[sandro]

@elfham that was a year ago. Is IRB in Ruby 3.1.2 really that old?

I have the problem with this sample code running against reline master with Ruby 3.1.2:

  require "reline"
  prompt = "> "

  begin
    while true
      text = Reline.readmultiline(prompt) do |data|
        puts "in", data
      end
      puts "you entered"
      puts text
    end
  rescue Interrupt
    puts "CTRL-C"
    exit 0
  end

Using Ctrl-Z works fine when using Ruby 3.0.1

[elfham]

Since this bug was introduced in #335, I believe that subsequent versions of Reline have had the problem.
(Reline 0.2.8~, Ruby 3.1.0~)

As I commented in #321 (comment) , I think commit #335 is inappropriate and should be reverted once.

[sandro]

@elfham Oh, my mistake, I thought you were saying the bug was fixed in #335 not that it was introduced there. Sorry for the confusion, and thanks for shedding light on this problem!

[casper]

Just installed Ruby 3.2.0 and ran into this same problem (Ubuntu Linux).
Strangely on Ruby 3.0, which also uses Reline, C-z works as expected.

[brasic]

I can confirm that this is still an issue in main for all ruby versions and that it's caused by #335. I use the following awkward monkeypatch in .irbrc to restore the ability to suspend irb with C-z:

module Signal
  @real_trap = method(:trap)
  def self.trap(*args, &block)
    if args[0] != 'TSTP'
      @real_trap.call(*args, &block)
    end
  end
end

I've opened #535 to revert the prior PR, as I don't believe it does anything useful.