TTY Input Buffer Issue

Zach_Dennis · 7 March 2015 20:18

I've got a strange input buffer issue that seems to exist with a
combination of OSX/Bash/Ruby.

It seems that after suspending a child process of Ruby with SIGTSTP the
first character (or the first line) will get put in the wrong buffer.

Would anyone mind taking a look and seeing if I'm doing or not doing
something stupid?

gist.github.com

https://gist.github.com/zdennis/3a0b685047ac086725b0

readme.md

* Make sure you are running the bash shell.
* Run `repl.rb` which will echo what you print unless you enter "irb".
* Type "irb" to launch a new irb process.
* Hit Ctrl-Z to send SIGTSTP to stop the irb process.
* You'll be brought back to the main repl. 
* Type "foo", hit enter. You'll be echoed "oo".
* Type "foo" again, hit enter. You'll see "foo".
* Now hit Ctrl-C to interrupt the process, it will die and the missing "f" will show up.

This seems to not be a problem with irb, but any child process that calls "gets". If you launch "irb" from bash though and do the same steps, bash doesn't exhibit this issue, just a ruby REPL.

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repl.rb

Signal.trap("SIGTSTP", "IGNORE")

pids = []
stty_save = `stty -g`
loop do
  print "#{$0}> "
  input = STDIN.gets.chomp
  if input == "exit"
    exit
  else

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TIA,

···

--
@zachdennis
http://www.continuousthinking.com

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TTY Input Buffer Issue

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