Drop support for JRuby 1.7

[flavorjones]

See jruby/jruby#4112 for background on JRuby 1.7 reaching EOL last year.

Also see our CI builds going red because Rake has ended support for "ruby 1.9" which is what JRuby self-identifies as.

[flavorjones]

Things to do here:

• remove from Concourse CI (see 308d70c which was reverted)
• remove from Travis CI
• update gem spec which currently says :required_ruby_version => '>= 1.9.3' # JRuby >= 1.7\
• look at ext/java/nokogiri/XmlSyntaxError.java and ext/java/nokogiri/internals/NokogiriHelpers.java which appear to have 1.7-specific code that can be removed

[flavorjones]

Note: JRuby 1.7 was removed from the CI pipelines when concourse-gem v0.19.0 dropped in September.

Note: the .travis.yml file hasn't been changed since Feb 2018 which reinforces my belief that it's unused and unnecessary. Also, I turned off Travis builds 10 months ago and nobody has noticed. I am going to delete the travis config file.

So the updated punch list is:

• delete Travis config file
• update gem spec
• look at code that has 1.7-specific handling

[flavorjones]

@jvshahid I'm curious if you see any other JRuby code that's specific to 1.7 support (or Ruby 1.9 support)?

Notably, in ext/java/nokogiri/XmlSyntaxError.java the to_s19 method appears to still be required on JRuby 9.2.x.x despite being explicitly commented as specific to JRuby 1.7 and named after Ruby 1.9 string handling.

[flavorjones]

@jvshahid bumping this. I think what I have on master is OK and so if you can't take a look I'll probably proceed anyway.

[jvshahid]

I took a quick look and couldn't find anything besides the few comments we had. I'm not sure if there is an easy way to discover things that we can remove other than trying them out. I made a few changes locally to stop using deprecated JRuby APIs. I don't think it is a blocker though. I will probably push those to a PR in the next few hours to test the changes in CI.

[flavorjones]

Word, OK. I'm going to close this, then. Thanks, @jvshahid!

[kares]

Notably, in ext/java/nokogiri/XmlSyntaxError.java the to_s19 method appears to still be required on JRuby 9.2.x.x despite being explicitly commented as specific to JRuby 1.7 and named after Ruby 1.9 string handling.

most of the is1_9 checking (and pre 1.9 missing encoding logic etc) was already gone, recall did update the above mentioned piece and it should be working fine on 9K but we should also change the signature to avoid (future) deprecation warnings. guess @jvshahid already has those.

btw. I did notice CI builds missing :) 1edf503 ... what's the status there, would you guys care to get Travis builds back or are they problematic to manage (we could simplify or allow failures)?

[flavorjones]

Can you help me understand what you're perceiving as "missing" with respect to CI? We have CI running a multi-ruby cross-platform build suite on every commit on master and every PR at https://ci.nokogiri.org/.