How to do an "OR" when requiring a Gem version

Question

Currently I have a Gemspec that requires a specific version of Rails 3.x with Rails > 3.1:

Gem::Specification.new do |s|
  # (...)
  s.add_dependency "railties", "~> 3.1"
  # (...)
end

I am looking to update this statement to require ~> 3.1 OR ~> 4.0.0. I had tried already:

~> 3.1, ~> 4.0.0
~> 3.1 OR ~> 4.0.0
~> 3.1 || ~> 4.0.0
~> 3.1 ~> 4.0.0

None have worked. Is that possible with the current RubyGems version?

For now I am using > 3.1, but the real question is if that's possible.

This is an interesting requirement. Let's see if a solution will arise. — Sergio Tulentsev, Sep 16 '12 at 13:56
@TonyHopkinson I know that my Gem is compatible with ~> 3.1 (3.1.x, 3.2.x) and compatible with ~> 4.0.0 (4.0.x), but I am not sure it will work with Rails 4.1.x. — jmonteiro, Sep 24 '12 at 19:59

score 2 · Accepted Answer · answered Sep 16 '12 at 14:40

Since you are using ~>, it seems as if you are willing to use any version of the gem that is after 3.1, that is, any 3.x OR any 4.0.x, but not a 4.x where x is greater than 1.

If that is your intention, then according to the rubygems guide, you'll want to use a pattern like:

spec.add_dependency 'library', ['>= 3.1', '< 4.1']

I think it might be the addition of brackets that you need.

How to do an "OR" when requiring a Gem version

1 Answers1