IRB 1.2.1 (2019-12-24) (ruby) not compatible byexample

[eldipa]

Describe the bug

root@7a2b065b0459:/mnt# byexample -l shell,ruby --timeout 20 docs/languages/ruby.md 
[w] Initialization of Ruby Runner failed.
[!] Something went wrong processing the file 'docs/languages/ruby.md':
Prompt not found: the code is taking too long to finish or there is a syntax error.

Last 1000 bytes read:
▽

Rerun with -vvv to get a full stack trace.
^[[38;2Rroot@7a2b065b0459:/mnt# ;2R

IRB/pexpect breaks in a really weird way. It seems that IRB never prints the prompts which makes byexample time out and instead, it prints some weird symbols/bytes.

Expected behavior
It should work.

byexample version
byexample 10.0.1 (Python 3.8.5) - GNU GPLv3
irb 1.2.1 (2019-12-24)
ruby 2.7.0p0 (2019-12-25 revision 647ee6f091) [x86_64-linux-gnu]

irb(main):005:0> Reline::VERSION
=> "0.1.2"

reline is the new lib used by irb to implement the prompt which is probably the reason of this problem.

May not be related but:
https://github.com/ruby/reline/blob/master/lib/reline.rb
ruby/reline#207
https://github.com/ruby/reline/blob/d1a7e74aa432ca1dda4e94aa1389f22c08b59c58/lib/reline/line_editor.rb#L530

[fnordfish]

I'm using byexample -l ruby --options="-ruby-pretty-print" -x-shebang "ruby:%e %p -f --nocolorize %a"

[eldipa]

@fnordfish thanks for the tip!

I'm testing your solution but I'm still getting the same error (same version of ruby, irb and byexample than the ones in the initial description of this ticket).

However, I ran byexample successfully as follows:

byexample -l ruby -x-shebang "ruby:%e %p --nocolorize --nomultiline %a" a.md

So a lot of thanks!

Could you confirm me that that my setting works for you?

I will add it as fix in the next version (I'm going to take some time before the release because I need to figure out how to do the change without breaking older versions of irb).

As a side note I saw that you opened an issue in the IRB project (ruby/irb#241) about a spurious new line after the => marker.

You can workaround it quickly with something like:

>> somecode
=><...>expected output

Or,

>> somecode    # byexample: +norm-ws
=> expected output

Unfortunately I couldn't trigger it in my environment so I couldn't test it (I think that the issue happens only in IRB >= 1.3.0).

I will keep an eye on that issue: if there is not response from the IRB developers I will try to add a workaround in byexample.

[fnordfish]

I've added the -f to make sure ~/.irbrc is ignored. For completeness, here's the shell script I've been using:

byexample -l ruby \
--options="-ruby-pretty-print" \
-x-shebang "ruby:%e %p -f --nomultiline --nocolorize %a -r bundler/setup -r ./_pages/docs/docs_base.rb -r my_lib" \
 $@ \
$(ruby -e 'puts Dir["_pages/**/*.{rb,md}"]')

(I know, I could have used find for the file patterns, but didn't want to care about potential differences between different operating systems)

Because I'm lazy, I've added those -r directly into my script to load the library code needed to test the docs.

[fnordfish]

BTW: Thanks for workaround, but I'd rather pin my irb dependency to a working version (1.3.0 is fine. 1.3.1 to 1.3.5 have that weird extra new line)
Just tested my script on ruby 2.7.0 and it's working fine.

Little note on irb dependency pin using bundler:

With a Gemfile like this:

# Gemfile
# ...
group :development, :test do
  gem "irb", ">= 1.2.7", "< 1.3.1", platform: :mri
end

I have to use bundle exec in the shebang, to make sure the correct irb version is used:
-x-shebang "ruby:bundle exec %e %p ${irb_opts} %a ${irb_r}"
Again, the bundle exec is only needed, if you're installing ruby dependencies via bundler.

If you just install a specific irb version manually like gem install irb -v 1.3.0, you can use a shebang like this:
-x-shebang "ruby:%e %p _1.3.0_ ${irb_opts} %a ${irb_r}"

[eldipa]

I found that IRB >= 1.2.2 added on purpose the newline after the => marker if the output is multiline.

The feature was introduced in this commit: https://github.com/ruby/irb/blob/2eb7d9cdca63a443ce220debe1b9669ffdd926db/lib/irb/context.rb#L274-L285

The idea is to fix this from byexample restoring the behavior of IRB < 1.2.2 (see cc226a7) and allowing the user to switch to the newer behavior of IRB >= 1.2.2 if he/she wants (see e0916fa)

[eldipa]

@fnordfish I released byexample 10.0.4. This issue and the issue of the "unexpected newline" (ruby/irb#241) should be fixed by now.

Let me know if you find any trouble.

By the way, since 10.0.3 you can use "file patterns" to select which files you want to execute.

For example:

$ byexample -l ruby '_pages/**/*.rb'  '_pages/**/*.md'

You need to protect those patterns with single quotes so it is byexample and not the shell who will interpret them. They are not as powerful as Ruby's (this will not work: _pages/**/*.{rb,md}) but something is something.

[fnordfish]

Brilliant. Thanks! Will give at a go.