Treat locales with variants case insensitively

[nampas]

We've noticed a few clients sending along funny locales like English

These result in the following error:

I18n::InvalidLocale: "En" is not a valid locale

That's happening because the locale variant match is case insensitive:
https://github.com/rack/rack-contrib/blob/main/lib/rack/contrib/locale.rb#L91

But then the locale is extracted without a downcase.

I believe it should be safe to just downcase the locale from the client in these cases.

[mpalmer]

While I'm loathe to do anything that encourages people to send broken request headers (:scream_cat:), the RFCs say that locale specifiers are case-insensitive, so your change is a win for that reason.

[nampas]

@mpalmer Thanks for the quick response on this. So quick that I wasn't able to verify that the unit test I added works 😮 My bad. I was having some trouble getting dependencies installed and happy on my machine. Are you seeing the test passing in main? Nvrm, I see that CI is passing so that's probably a good sign.

[mpalmer]

Yeah, if CI passes, it seems reasonable to assume it's working. What were the errors you were seeing locally?

[nampas]

Following the instructions here, I was seeing this from a fresh clone of the repo:

➜  rack-contrib (main) ✗ mise activate
...
➜  rack-contrib (main) ✗ which ruby
/Users/nathanpastor/.local/share/mise/installs/ruby/3.3.3/bin/ruby
➜  rack-contrib (main) ✗ gem install json rack ruby-prof test-spec test-unit
Building native extensions. This could take a while...
Successfully installed json-2.7.5
...
5 gems installed

A new release of RubyGems is available: 3.5.15 → 3.5.22!
Run `gem update --system 3.5.22` to update your installation.

➜  rack-contrib (main) ✗ rake test
...
<internal:/Users/nathanpastor/.local/share/mise/installs/ruby/3.3.3/lib/ruby/site_ruby/3.3.0/rubygems/core_ext/kernel_require.rb>:136:in `require': cannot load such file -- timecop (LoadError)

If I add timecop to the list of gems to install, then rake test fails with:

<internal:/Users/nathanpastor/.local/share/mise/installs/ruby/3.3.3/lib/ruby/site_ruby/3.3.0/rubygems/core_ext/kernel_require.rb>:136:in `require': cannot load such file -- minitest/hooks

I think that was around where I stopped, because I wasn't sure how many more dependencies I'd need to install. But, as one last hurrah, I tried a bundle install, which led to rake test failing with

<internal:/Users/nathanpastor/.local/share/mise/installs/ruby/3.3.3/lib/ruby/site_ruby/3.3.0/rubygems/core_ext/kernel_require.rb>:136:in `require': cannot load such file -- rails/test_unit/reporter

[mpalmer]

Whoof, yeah, those instructions are waaaay out of date (as evidenced by the fact that it mentions Ruby 1.8...) I'll make an issue to get that sorted out, but in the meantime, CI says everything's good, and that's good enough for me. 🎉

[ioquatix]

This code base could do with a lot of TLC, feel free to take the lead on updating it if you have the time and energy to do so.

[nampas]

Ok I will try to get the readme updated at least. Thanks for the assistance y'all 🙏