#sum method breaks with Ruby 2.4

[moveson]

Rails does some gymnastics to use the Enumerable#sum method built into Ruby 2.4+, and it falls back to the ActiveSupport Enumerable#sum method to handle situations in which the Ruby method doesn't handle it, such as an Array of Strings. Unfortunately, DescriptiveStatistics' #sum method gets in the way and breaks things when the Array is empty.

Using Ruby 2.4.2 and Rails 5.1.4 with descriptive_statistics 2.5.1:

>> [].sum
#> NoMethodError: undefined method `each' for nil:NilClass

See this post on StackOverflow for details.

[mhluska]

@moveson how did you solve this?

[moveson]

@mhluska I got no response from this issue, so I was forced to remove this gem.

[nsoseka]

If you read the docs carefully you will notice there is a way of working with the gem without using the monkey patch approach which is what will solve your problem. Import refinements and include descriptive_statistics on the objects you want to use it on

[arushs]

@thirtysixthspan This doesn't look like it's been solved. Is there anything blocking from pushing a PR and merging it? Is it blocked by supporting Ruby 2.4?

[curious725]

@moveson You didn't used gem in the right way.
I have prototyped this situation
One option that you have - add gem descriptive_statistics in your Gemfile:
gem 'descriptive_statistics', require: false
and then use safe version

require 'descriptive_statistics/safe'

data = []
data.extend(DescriptiveStatistics)
data.sum

In that way everything works.

[mzaharie]

With rake tasks I had to do the import inside the task block like:

  task my_task: :environment do
    require 'word-to-markdown' # avoid it being auto loaded in other tasks

This way I can safely work with rails 7 models in other tasks.

Note, word-to-markdown uses descriptive_statistics