Monkey-patched `Array#sum` method changes/breaks Ruby 2.4 method functionality

[sjdemartini]

In lib/statsample.rb, the core Ruby Array class is monkey-patched to change the behavior of the sum method:

statsample/lib/statsample.rb

Lines 57 to 59 in 0f283e2

	def sum
	inject(:+)
	end

Active Support (included by Rails) already defines behavior for #sum, which has slightly different behavior and can accept a block for evaluation: https://github.com/rails/rails/blob/3d716b9e66e334c113c98fb3fc4bcf8a945b93a1/activesupport/lib/active_support/core_ext/enumerable.rb#L2-L27

Similarly, the Ruby core library added the #sum method to the Enumerable class in Ruby 2.4:

• https://ruby-doc.org/core-2.4.1/Enumerable.html
• http://blog.bigbinary.com/2016/11/02/ruby-2-4-introduces-enumerable-sum.html
• ruby/ruby@41ef7ec

As such, for example, the following code works both with Active Support and/or Ruby 2.4:

> x = ['foo', 'bar']
#=> ["foo", "bar"]
> x.sum(&:bytesize)
#=> 6

But fails when the statsample 2.0 library is included in the project's Gemfile:

> x = ['foo', 'bar']
#=> ["foo", "bar"]
> x.sum(&:bytesize)
#=> "foobar"

Can this monkey-patching be removed and the suming functionality be done directly only where needed? This is preventing me from using statsample, unfortunately.

[NOX73]

🤦‍♂️
+1

[v0dro]

Can you send a PR with the monkey patching removed and replace instances of Array#sum with an appropriate method?

[sjdemartini]

I don't have the time myself to fix this, unfortunately.

[IsmailM]

We had this issue as well - We simply patched over it again after requiring statsample - not ideal (or clean) but solved the issue for us.

Imo It would be best to avoid global monkey patch - they will have unintended side-effects and break other ruby functions and make it hard to debug when they go wrong (I had no idea it was Statsample monkey-patching when I first saw this issue)...

Any chance this could be implemented as a Refinement -

Alternatively, at the very least, put them into a separate class/module and then use inheritance to monkey-patch.

One potential implementation would be:

module StatSample
  module ArrayExtensions
    def sum
      ....
    end 
  end 
end 

class Array
   include StatSample::ArrayExtensions
end

See https://www.justinweiss.com/articles/3-ways-to-monkey-patch-without-making-a-mess/