Optional gem dependency problems

[robd]

I'm not sure if this was intentional, but this change:

group :extras, :optional => true

Caused my call to rake to fail like this:

airbrussh:rake
There was an error in your Gemfile, and Bundler cannot continue.

I tried bundle install and I got this:

bundle install
/Users/robd/.rbenv/versions/2.2.2/lib/ruby/gems/2.2.0/gems/bundler-1.9.4/lib/bundler/dependency.rb:54:in `block in initialize': undefined method `to_sym' for {:optional=>true}:Hash (NoMethodError)

Basically, looks like :optional => true is not backwards compatible with older versions of bundler. I'm not sure if this was intentional - looks like the intention was for v1.10 of bundler to only be needed for people who wanted to run the optional tasks, but this doesn't work - everyone needs v1.10.

I upgraded bundler, reinstalled the gems and then I saw:

airbrussh:rake                                                                                                                                                                        2.2.2
rake aborted!
LoadError: cannot load such file -- chandler/tasks
/Users/robd/dev/airbrussh/Rakefile:14:in `require'

This can be fixed by patching the rake file like this, (but I don't know what gem version find_all_by_name was added):

if !ENV["TRAVIS"] &&  Gem::Specification::find_all_by_name('chandler').any?
  require "chandler/tasks"
  task "release:rubygem_push" => "chandler:push"
end

I'm not sure what the motivation was as far as making some gems optional. I think it is a nice idea in principle, but I wonder if the complexity of trying to make them optional is worth it. Personally I'm happy to just install everything even if I don't use guard, chandler etc.

I'm happy to do a PR for this, but I wanted to discuss first to find out which direction it should go in.

[mattbrictson]

The conditional logic is necessary because guard and chandler do not work in 1.9.3. I believe Ruby 2.1 or higher is required for those. Bundler 1.10 adds some new features regarding optional dependencies, so I wanted to check if that would help solve this problem. Sounds like I didn't get it working quite right.

Maybe the Rakefile problem could be rewritten as:

begin
  require "chandler/tasks"
rescue LoadError
end
task "release:rubygem_push" => "chandler:push" if defined?(Chandler)

Then it just becomes a matter of whether to install the extra gems or not. Perhaps the better Bundler 1.10 feature to use in this case is install_if.

group :ruby_2, :install_if => -> { check_ruby_gte_2_1_0 } do
  #...
end

I mentioned in the CHANGELOG that Bundler 1.10 is now a requirement. Maybe that should go in CONTRIBUTING as well.

[mattbrictson]

I will make the above change to the Rakefile, which will solve the immediate problem. I'm still open to discuss whether the Bundler 1.10 requirement is unreasonable or if bundle install --with extras is a unnecessary step that we should do away with.

[huerlisi]

I think this issue can be closed. It's been fine for me to work with and is properly documented in the contributor documentation.

Bundler >= 1.10 is fine nowadays;-)

I think dropping support for 1.9 could be a topic for the next major release. But as long as it's no pain, this compatibility is a 👍