Posted by Andrew Carver on Jun 16, 2019; 1:08pm
URL: https://discuss.asciidoctor.org/nokogiri-error-when-installing-asciidoctor-epub3-tp6733p6957.html

P.S. I'm also baffled by asciidoctor 2.0.10 installing just fine without installing nokogiri...??
(I think the below warning about "the last version of nokogiri ... to support your Ruby & RubyGems  was 1.8.5" was probably because I'd already installed asciidoctor 1.5.8, which depends on that version.)

Andrew Carver wrote

Thanks Dan.
May I ask you, then, whether the below sequence run just now on Ruby 2.6.x indicates the nokogiri dependency needs upgrading in asciidoctor-bibliography?

C:\Users\acarver>gem install nokogiri -v 1.8.5
ERROR:  Error installing nokogiri:
        The last version of nokogiri (= 1.8.5) to support your Ruby & RubyGems was 1.8.5. Try installing it with `gem install nokogiri -v 1.8.5`
        nokogiri requires Ruby version >= 2.2, < 2.6. The current ruby version is 2.6.3.62.

C:\Users\acarver>gem install asciidoctor
Fetching asciidoctor-2.0.10.gem
Successfully installed asciidoctor-2.0.10
Parsing documentation for asciidoctor-2.0.10
Installing ri documentation for asciidoctor-2.0.10
Done installing documentation for asciidoctor after 15 seconds
1 gem installed

C:\Users\acarver>gem install asciidoctor-bibliography
ERROR:  Error installing asciidoctor-bibliography:
        The last version of nokogiri (~> 1.8.1) to support your Ruby & RubyGems was 1.8.5. Try installing it with `gem install nokogiri -v 1.8.5` and then running the current command again
        nokogiri requires Ruby version >= 2.2, < 2.6. The current ruby version is 2.6.3.62.