Fixnum is deprecated in upcoming ruby version

[nimish-mehta]

Fixnum and Bignum are being deprecated in ruby version 2.4
https://bugs.ruby-lang.org/issues/12739, use 0.class to
handle the transition

[macournoyer]

Thanks!

[janko]

I'm curious, why not just use Integer instead of 0.class? I thought that was the idea behind deprecation of Fixnum, that we don't have to differentiate between Fixnum and Bignum anymore.

[junaruga]

@janko-m I think that it is compatibility for Ruby < 2.4.0. you can see the 0.class hack in famous rubygem packages.

Below are for Rails (rails/rails).

$ git clone https://github.com/rails/rails.git
$ cd rails
$ grep -r '0\.class' *
activerecord/test/cases/query_cache_test.rb:        assert_instance_of 0.class, Task.connection.select_value("SELECT count(*) AS count_all FROM tasks")
activesupport/test/core_ext/array/grouping_test.rb:    Fixnum.send :private, :/ unless 0.class == Integer
activesupport/test/core_ext/array/grouping_test.rb:    Fixnum.send :public, :/ unless 0.class == Integer
activesupport/lib/active_support/core_ext/numeric/conversions.rb:if 0.class == Integer
activesupport/lib/active_support/xml_mini.rb:      TYPE_NAMES["Fixnum"] = "integer" unless 0.class == Integer
activesupport/lib/active_support/xml_mini.rb:      TYPE_NAMES["Bignum"] = "integer" unless 0.class == Integer

[nimish-mehta]

@janko-m @junaruga
I just tested this out: https://gist.github.com/nimish-mehta/b6b7d49711eafbb3fcb7f50fd5c79849.
Integer would have worked out just as well. I did know about this when i made the PR 😞

[ttanimichi]

Are you planning to release this in the next version?

[macournoyer]

Just released yesterday.

[KelseyDH]

Would it be possible to backport this fix to thin version 1.5?

The folks over at mailcatcher relying on the skinny gem don't have an easy upgrade path to later versions of thin, so this deprecation message still shows up when they use thin 1.5. So backporting this fix, or alternatively helping skinny upgrade to a newer version of thin 1.7, would be much appreciated.