Always entering debugger in Ruby 2.7 (4.0.0.rc1)

[riccardoporreca]

When running htmlproofer 4.0.0.rc1 on Ruby 2.7, it seems to always trigger the debugger. This does not occur on Ruby 3.1.

I tested this in a reproducible way in a "fresh" Ruby installation using Docker via

docker run --rm -it ruby:2.7 bash
gem install html-proofer -v 4.0.0.rc1

Just asking for the version reveals the issue

$ ruby -v
ruby 2.7.5p203 (2021-11-24 revision f69aeb8314) [x86_64-linux]
$ htmlproofer -v
usr/local/lib/ruby/2.7.0/x86_64-linux/continuation.so: warning: callcc is obsolete; use Fiber instead
Debug.rb
Emacs support available.

/usr/local/lib/ruby/2.7.0/rubygems/core_ext/kernel_require.rb:162:    if RUBYGEMS_ACTIVATION_MONITOR.respond_to?(:mon_owned?)
(rdb:1) n
/usr/local/lib/ruby/2.7.0/rubygems/core_ext/kernel_require.rb:163:      if monitor_owned != (ow = RUBYGEMS_ACTIVATION_MONITOR.mon_owned?)
(rdb:1) n
/usr/local/bundle/gems/zeitwerk-2.5.3/lib/zeitwerk/kernel.rb:36:      if required
(rdb:1) n
/usr/local/bundle/gems/zeitwerk-2.5.3/lib/zeitwerk/kernel.rb:37:        abspath = $LOADED_FEATURES.last
(rdb:1) n
/usr/local/bundle/gems/zeitwerk-2.5.3/lib/zeitwerk/kernel.rb:38:        if loader = Zeitwerk::Registry.loader_for(abspath)
(rdb:1) n
/usr/local/bundle/gems/zeitwerk-2.5.3/lib/zeitwerk/kernel.rb:42:      required
(rdb:1) n
/usr/local/bundle/gems/html-proofer-4.0.0.rc1/lib/html_proofer.rb:21:module HTMLProofer
(rdb:1) n
/usr/local/bundle/gems/html-proofer-4.0.0.rc1/lib/html_proofer.rb:56:gem_loader.eager_load
(rdb:1) n
/usr/local/lib/ruby/2.7.0/rubygems/core_ext/kernel_require.rb:162:    if RUBYGEMS_ACTIVATION_MONITOR.respond_to?(:mon_owned?)
(rdb:1) n
/usr/local/lib/ruby/2.7.0/rubygems/core_ext/kernel_require.rb:163:      if monitor_owned != (ow = RUBYGEMS_ACTIVATION_MONITOR.mon_owned?)
(rdb:1) n
/usr/local/bundle/gems/html-proofer-4.0.0.rc1/bin/htmlproofer:9:require 'mercenary'
(rdb:1) n
/usr/local/bundle/gems/html-proofer-4.0.0.rc1/bin/htmlproofer:11:Mercenary.program(:htmlproofer) do |p|
(rdb:1) n
htmlproofer 4.0.0.rc1

UPDATE The same occurs with a yet more minimal example of simply requiring html-proofer

ruby -e "require 'html-proofer'"

[riccardoporreca]

Even worse on Ruby 3.0.3, with an error raised

$ ruby -v
ruby 3.0.3p157 (2021-11-24 revision 3fb7d2cadc) [x86_64-linux]
$ ruby -e "require 'html-proofer'"
/usr/local/lib/ruby/3.0.0/debug.rb:6:in `<top (required)>': undefined method `>' for nil:NilClass (NoMethodError)
        from <internal:/usr/local/lib/ruby/3.0.0/rubygems/core_ext/kernel_require.rb>:85:in `require'
        from <internal:/usr/local/lib/ruby/3.0.0/rubygems/core_ext/kernel_require.rb>:85:in `require'
        from /usr/local/bundle/gems/zeitwerk-2.5.3/lib/zeitwerk/kernel.rb:35:in `require'
        from /usr/local/bundle/gems/html-proofer-4.0.0.rc1/lib/html_proofer.rb:18:in `block in <top (required)>'
        from /usr/local/bundle/gems/html-proofer-4.0.0.rc1/lib/html_proofer.rb:17:in `each'
        from /usr/local/bundle/gems/html-proofer-4.0.0.rc1/lib/html_proofer.rb:17:in `<top (required)>'
        from /usr/local/bundle/gems/html-proofer-4.0.0.rc1/lib/html-proofer.rb:3:in `require_relative'
        from /usr/local/bundle/gems/html-proofer-4.0.0.rc1/lib/html-proofer.rb:3:in `<top (required)>'
        from <internal:/usr/local/lib/ruby/3.0.0/rubygems/core_ext/kernel_require.rb>:160:in `require'
        from <internal:/usr/local/lib/ruby/3.0.0/rubygems/core_ext/kernel_require.rb>:160:in `rescue in require'
        from <internal:/usr/local/lib/ruby/3.0.0/rubygems/core_ext/kernel_require.rb>:149:in `require'
        from -e:1:in `<main>'
<internal:/usr/local/lib/ruby/3.0.0/rubygems/core_ext/kernel_require.rb>:85:in `require': cannot load such file -- html-proofer (LoadError)
        from <internal:/usr/local/lib/ruby/3.0.0/rubygems/core_ext/kernel_require.rb>:85:in `require'
        from -e:1:in `<main>'

This seems to point to

html-proofer/lib/html_proofer.rb

Lines 17 to 18 in fda9ef4

	%w[awesome_print debug].each do |gem|
	require gem

where there is something related to debugging.

[riccardoporreca]

I also found a possibly related ruby/debug#275 and PR ruby/debug#278. I tried to give a go to the approach used in the PR (
https://github.com/ruby/debug/blob/2e5482064aa27d20d1432abf8e13ad064199ae9d/lib/debug/session.rb#L26-L28), as follows:

$ ruby -v
ruby 3.0.3p157 (2021-11-24 revision 3fb7d2cadc) [x86_64-linux]
$ ruby -e "\$LOADED_FEATURES << 'debug.rb'; require 'html-proofer'"

which does not error (nor enters the debugger on 2.7)

Hope this helps.

[riccardoporreca]

I can confirm requiring debug in

html-proofer/lib/html_proofer.rb

Lines 17 to 18 in fda9ef4

	%w[awesome_print debug].each do |gem|
	require gem

is the root cause of the issues in both Ruby 3.0 and 2.7

$ docker run --rm ruby:3.0.3 ruby -e "require 'debug'"
/usr/local/lib/ruby/3.0.0/debug.rb:6:in `<top (required)>': undefined method `>' for nil:NilClass (NoMethodError)
        from <internal:/usr/local/lib/ruby/3.0.0/rubygems/core_ext/kernel_require.rb>:85:in `require'
        from <internal:/usr/local/lib/ruby/3.0.0/rubygems/core_ext/kernel_require.rb>:85:in `require'
        from -e:1:in `<main>'
$  docker run --rm ruby:2.7.5 ruby -e "require 'debug'"
/usr/local/lib/ruby/2.7.0/x86_64-linux/continuation.so: warning: callcc is obsolete; use Fiber instead
(rdb:1) Debug.rb
Emacs support available.

/usr/local/lib/ruby/2.7.0/rubygems/core_ext/kernel_require.rb:162:    if RUBYGEMS_ACTIVATION_MONITOR.respond_to?(:mon_owned?)

[gjtorikian]

I wonder why CI didn't complain about this? Thanks for finding it. I'm just going to comment the gem out, it's non-essential.

[riccardoporreca]

@gjtorikian, thanks for quick fix(es)!

I still see this happening with 4.0.0.rc2: I guess it is key to also prevent requiring debug in

html-proofer/lib/html_proofer.rb

Lines 17 to 18 in fda9ef4

	%w[awesome_print debug].each do |gem|
	require gem

Good point about CI... but it seems like entering the debugger does not bother the CI, but we still see it in the logs there, see the 4.0.0.rc2 jobs:

• 2.7.5: https://github.com/gjtorikian/html-proofer/runs/4732151627?check_suite_focus=true#step:6:8
• 3.0.0: https://github.com/gjtorikian/html-proofer/runs/4732151583?check_suite_focus=true#step:6:8

(Un)likely, 3.0.0 indeed just enters the debugger as 2.7.5 (could confirm locally with Docker), as opposed to the error I see with 3.0.3 does, which might have broken CI.

[gjtorikian]

Ohhh damn it, I understand what’s happening now. Ugh! Thank you for your patience.