Avoid playing with `Oj` shared `default_options`

[BuonOmo]

rabl/lib/rabl/configuration.rb

Line 22 in 02b3464

Oj.default_options = { :mode => :compat, :time_format => :ruby, :use_to_json => true }

This line causes a lot of trouble for anyone using Oj and requiring rabl after having set Oj themselves:

Oj.default_options = my = { mode: :strict }
require "rabl"

Oj.default_options != my

Oj has its share of responsibility on that, however, IMHO the bug comes from rabl.

I'd love to fix it by using MultiJson, yet I came across one of your commits removing it (9bfb1a4).

Another option may be to have a condition in the format_json method, but I'm not a big fan..

[nesquena]

Thanks for the report, I agree this is an issue. However, I am unclear of the cleanest way to solve it. I'll give it some thought 🤔 . MultiJson was removed just to streamline and remove dependencies. If anyone wants to submit a PR that they think fixes this relatively cleanly, I'd be happy to review, consider, and merge as well.

[BuonOmo]

@nesquena well:

• MultiJson is more downloaded than Rack or Rails (https://rubygems.org/stats) hence there are great chances one already depends to multi_json in its Gemfile,
• It is only 1.2k LOC (rabl is 1.7k for instance),
• On my computer, repositories have in average 1 dependency that itself depends on MultiJson:

  `rg multi_json **/Gemfile.lock -c`.split.map { _1[/\d+\z/].to_i - 1 }.sum / `fd Gemfile.lock | wc -l`.to_i

Hence I'd be incline to add it back 🙂