undefined method `position' for #<Nokogiri::XML::Element:0x0000000002465008> (NoMethodError)

[deivid-rodriguez]

In order to generate bundler's man pages, we currently use the ronn gem. However, this gem and its dependencies have not been updated for years, and just now I found out that they started segfaulting in some situations.

I tried replacing ronn with ronn-ng. It did generate some man pages (didn't check correctness, but it didn't crash), but it ended up crashing with the following error

/home/travis/.rvm/rubies/ruby-2.6.1/bin/ruby -S ronn --roff --pipe man/gemfile.5.ronn > man/gemfile.5
warn: unrecognized inline tag: ["p"]
warn: unrecognized inline tag: ["p"]
warn: unrecognized inline tag: ["p"]
Traceback (most recent call last):
	23: from /home/travis/.rvm/gems/ruby-2.6.1/bin/ronn:23:in `<main>'
	22: from /home/travis/.rvm/gems/ruby-2.6.1/bin/ronn:23:in `load'
	21: from /home/travis/.rvm/gems/ruby-2.6.1/gems/ronn-ng-0.8.0.SNAPSHOT/bin/ronn:184:in `<top (required)>'
	20: from /home/travis/.rvm/gems/ruby-2.6.1/gems/ronn-ng-0.8.0.SNAPSHOT/bin/ronn:184:in `each'
	19: from /home/travis/.rvm/gems/ruby-2.6.1/gems/ronn-ng-0.8.0.SNAPSHOT/bin/ronn:199:in `block in <top (required)>'
	18: from /home/travis/.rvm/gems/ruby-2.6.1/gems/ronn-ng-0.8.0.SNAPSHOT/bin/ronn:199:in `each'
	17: from /home/travis/.rvm/gems/ruby-2.6.1/gems/ronn-ng-0.8.0.SNAPSHOT/bin/ronn:220:in `block (2 levels) in <top (required)>'
	16: from /home/travis/.rvm/gems/ruby-2.6.1/gems/ronn-ng-0.8.0.SNAPSHOT/lib/ronn/document.rb:238:in `convert'
	15: from /home/travis/.rvm/gems/ruby-2.6.1/gems/ronn-ng-0.8.0.SNAPSHOT/lib/ronn/document.rb:243:in `to_roff'
	14: from /home/travis/.rvm/gems/ruby-2.6.1/gems/ronn-ng-0.8.0.SNAPSHOT/lib/ronn/document.rb:243:in `new'
	13: from /home/travis/.rvm/gems/ruby-2.6.1/gems/ronn-ng-0.8.0.SNAPSHOT/lib/ronn/roff.rb:18:in `initialize'
	12: from /home/travis/.rvm/gems/ruby-2.6.1/gems/ronn-ng-0.8.0.SNAPSHOT/lib/ronn/roff.rb:91:in `block_filter'
	11: from /home/travis/.rvm/gems/ruby-2.6.1/gems/ronn-ng-0.8.0.SNAPSHOT/lib/ronn/roff.rb:88:in `block_filter'
	10: from /home/travis/.rvm/gems/ruby-2.6.1/gems/nokogiri-1.10.1/lib/nokogiri/xml/node_set.rb:237:in `each'
	 9: from /home/travis/.rvm/gems/ruby-2.6.1/gems/nokogiri-1.10.1/lib/nokogiri/xml/node_set.rb:237:in `upto'
	 8: from /home/travis/.rvm/gems/ruby-2.6.1/gems/nokogiri-1.10.1/lib/nokogiri/xml/node_set.rb:238:in `block in each'
	 7: from /home/travis/.rvm/gems/ruby-2.6.1/gems/ronn-ng-0.8.0.SNAPSHOT/lib/ronn/roff.rb:88:in `block in block_filter'
	 6: from /home/travis/.rvm/gems/ruby-2.6.1/gems/ronn-ng-0.8.0.SNAPSHOT/lib/ronn/roff.rb:160:in `block_filter'
	 5: from /home/travis/.rvm/gems/ruby-2.6.1/gems/ronn-ng-0.8.0.SNAPSHOT/lib/ronn/roff.rb:88:in `block_filter'
	 4: from /home/travis/.rvm/gems/ruby-2.6.1/gems/nokogiri-1.10.1/lib/nokogiri/xml/node_set.rb:237:in `each'
	 3: from /home/travis/.rvm/gems/ruby-2.6.1/gems/nokogiri-1.10.1/lib/nokogiri/xml/node_set.rb:237:in `upto'
	 2: from /home/travis/.rvm/gems/ruby-2.6.1/gems/nokogiri-1.10.1/lib/nokogiri/xml/node_set.rb:238:in `block in each'
	 1: from /home/travis/.rvm/gems/ruby-2.6.1/gems/ronn-ng-0.8.0.SNAPSHOT/lib/ronn/roff.rb:88:in `block in block_filter'
/home/travis/.rvm/gems/ruby-2.6.1/gems/ronn-ng-0.8.0.SNAPSHOT/lib/ronn/roff.rb:165:in `block_filter': undefined method `position' for #<Nokogiri::XML::Element:0x0000000002465008> (NoMethodError)

In order to reproduce, you can clone bundler, replace the ronn development dependency with ronn-ng, and then run bin/rake spec:deps followed by bin/rake man:build.

Thanks!

[ssgelm]

I ran into this also with git-lfs and it appears to be caused by having a numbered list. Any man pages without one work fine. Here's a really simple one that worked before but now fails:

test
====

## SYNOPSIS

 1. Test

[deivid-rodriguez]

Thanks @ssgelm for digging into it! This gem looks very promising if this is fixed! 🎉

[apjanke]

Thanks for the report! Prioritizing this bug since it's causing problems for Debian.

Looks like this could be a leftover bug from the hpricot-to-Nokogiri migration.

[ssgelm]

@apjanke Thanks for looking into it! Please let me know if I can help in any way.

[apjanke]

This was indeed an hpricot-to-Nokogiri migration bug.

It looks like one of those fabled one-line fixes: e91949f#diff-8c2a2b56f00218c211ba4fc3ed93077c

This fix won't fix all ordered list rendering: in particular, I don't know whether nested ordered lists are working well. But it fixes this regression and gets Ronn-NG back to what the original Ronn supported. And should get your man pages building.

I added an ordered list test to Ronn-NG's test suite, and the results look good to me, based on manual inspection and viewing under man on macOS.

Fixes the git-lfs man build failure for me, though I haven't inspected the resulting pages for correctness.

Before:

[~/local/repos/git-lfs]
$ make man                                                                                                     testing-ronn-ng
ronn  -r --pipe < docs/man/git-lfs-checkout.1.ronn > man/git-lfs-checkout.1
ronn  -r --pipe < docs/man/git-lfs-clean.1.ronn > man/git-lfs-clean.1
[...]
ronn  -r --pipe < docs/man/git-lfs.1.ronn > man/git-lfs.1
Traceback (most recent call last):
	23: from /usr/local/Cellar/ronn-ng/0.8.0/libexec/bin/ronn:23:in `<main>'
	22: from /usr/local/Cellar/ronn-ng/0.8.0/libexec/bin/ronn:23:in `load'
[...]
	 2: from /usr/local/lib/ruby/gems/2.6.0/gems/nokogiri-1.10.1/lib/nokogiri/xml/node_set.rb:238:in `block in each'
	 1: from /usr/local/Cellar/ronn-ng/0.8.0/libexec/gems/ronn-ng-0.8.0/lib/ronn/roff.rb:88:in `block in block_filter'
/usr/local/Cellar/ronn-ng/0.8.0/libexec/gems/ronn-ng-0.8.0/lib/ronn/roff.rb:165:in `block_filter': undefined method `position' for #<Nokogiri::XML::Element:0x00007fdf5990f048> (NoMethodError)
make: *** [man/git-lfs.1] Error 1

After:

[~/local/repos/git-lfs]
$ make man                                                                                    testing-ronn-ng
ronn  -5 --pipe < docs/man/git-lfs-checkout.1.ronn > man/git-lfs-checkout.1.html
ronn  -5 --pipe < docs/man/git-lfs-clean.1.ronn > man/git-lfs-clean.1.html
[...]
ronn  -5 --pipe < docs/man/git-lfs.1.ronn > man/git-lfs.1.html
[~/local/repos/git-lfs]
$

This fix justifies a patch release since the problem is affecting end users and especially because it's a regression from original Ronn.

I've pushed out an 0.8.1.beta.1 release with this fix included. Can you test it out? Install with brew install ronn-ng --devel on macOS or gem install ronn-ng --pre on other platforms.

[apjanke]

@deivid-rodriguez I think I've got this fixed for you, but I'm not enough of a Ruby wizard to get the bundler man page build working with the ronn-ng gem. Could you test it against the ronn-ng 0.8.1.beta.1 gem and see if it's working for you under that?

[ssgelm]

Seems to work for me. I diffed the old and new man pages and there seem to be some slight differences but none that cause obvious visual differences so I think it's fine.

[apjanke]

Great.

Yeah, the ROFF output isn't going to be byte-for-byte identical between Ronn and Ronn-NG – in particular, I've removed what I considered to be excess non-significant whitespace that hindered readability for experienced ROFF users (who are the only folks that should be reading raw ROFF files ;) ) – but it should render the same (in most cases) or “better” (in the case of nested lists or some other indented constructs).

[apjanke]

BTW, sorry for taking so long to respond to this bug report. I had food poisoning earlier this week. :(

[deivid-rodriguez]

Tried it and it worked just fine! As @ssgelm pointed out, I also diffed the generated man pages and they show minor changes that don't seem to make any visual difference.

So this seems fixed, thanks!!

[apjanke]

This fix went out in version 0.8.1.