rails error method_missing': undefined method `this' for Gem::Specification

Question

I follow this tutorial: https://guides.spreecommerce.com/developer/getting_started_tutorial.html#installing-image-magick When I write

jonstark@jonstark-pc:~/         


        

Answer 1

Downgrading from Ruby 2.3.0 to 2.2.0 fixed it for me

Answer 2

gem update --system 2.4.8 --no-ri --no-rdoc - fixed it details are here https://github.com/remomueller/documentation/issues/7

Answer 3

This was an issue in RubyGems 2.5.1 and it is fixed in RubyGems 2.6.3

Just update RubyGems to version 2.6.3 or greater.

gem update --system 2.6.3

Or if you use RVM (From alf's comment)

rvm rubygems 2.6.3