Few weeks ago I’ve found interesting bug with Ruby 2.3 and Rails 18.104.22.168. One of my pet projects is too old (haha) and I’m using Rails 22.214.171.124. After system updating to the latest MacOS Sierra, and rbenv with Ruby 2.3, my project starts with exception. Calling any relation raises very strange error:
After some googling I’ve found that troubles in the my current version of Active Record.
Linked Github issue.
So you can update your Rails to the 126.96.36.199 or use this initializer: