NameError（未初始化的常量Mongoid :: Relations :: Cascading :: DeleteAll）：

Question

I've been receiving the error below when trying to delete one of my applications from http://localhost:3000/api/v1/oauth/applications .

Started DELETE "/api/v1/oauth/applications/5930bd2aa54dd321f7248178" for ::1 
 at 2017-06-01 21:53:22 -0400
 Processing by Doorkeeper::ApplicationsController#destroy as HTML
Parameters: {"utf8"=>"✓", 
 "authenticity_token"=>"+IxdEDUYW65Hj99VUqdJ/rydjZjJE8CIFy7El5KuuZ0rf36wLE0M4qJxBUL61D1IeRW+VvgWw1o9ckXxpHBkVw==", "commit"=>"Destroy", "id"=>"5930bd2aa54dd321f7248178"}
MONGODB | localhost:27017 | playco_development.find | STARTED | {"find"=>"oauth_applications", "filter"=>{"_id"=>BSON::ObjectId('5930bd2aa54dd321f7248178')}}
MONGODB | localhost:27017 | playco_development.find | SUCCEEDED | 0.000784s
Completed 500 Internal Server Error in 9ms

NameError (uninitialized constant Mongoid::Relations::Cascading::DeleteAll):
  activesupport (4.2.8) lib/active_support/inflector/methods.rb:263:in `const_get'
  activesupport (4.2.8) lib/active_support/inflector/methods.rb:263:in `block in constantize'
  activesupport (4.2.8) lib/active_support/inflector/methods.rb:259:in `each'
  activesupport (4.2.8) lib/active_support/inflector/methods.rb:259:in `inject'
  activesupport (4.2.8) lib/active_support/inflector/methods.rb:259:in `constantize'
  activesupport (4.2.8) lib/active_support/core_ext/string/inflections.rb:66:in `constantize'
  mongoid (5.2.1) lib/mongoid/relations/metadata.rb:98:in `cascade_strategy'
  mongoid (5.2.1) lib/mongoid/relations/cascading.rb:30:in `block in cascade!'

Here are the gems I am using that are pertinent to mongoid and rails:

gem 'rails', '4.2.8'
gem 'mongoid', '~> 5.2.1'
gem 'doorkeeper-mongodb', github: 'doorkeeper-gem/doorkeeper-mongodb'
gem "doorkeeper-grants_assertion", github: "doorkeeper-gem/doorkeeper-grants_assertion"

This only happens when trying to 'destroy' an existing application from the UI.

Any help would be greatly appreciated.

Answer 1

The problem stemmed from gem 'doorkeeper-mongodb' requiring gem 'doorkeeper' at version >= 4.00. A version of gem 'doorkeeper' greater than v3.1.0 has a dependent: :delete_all association (see doorkeeper/lib/doorkeeper/models/application_mixin.rb within the doorkeeper gem file). A cascading relation of :delete_all is not supported in any of version of Mongoid to date and raises the NameError exception.

I got around this by requiring gem 'doorkeeper', '~> 3.1.0' . However this caused a gem dependency issue with gem 'doorkeeper-grants_assertion' which I fixed by requesting a specific commit version in my gem file as seen below:

gem 'mongoid', '~> 5.1.0'
gem 'doorkeeper-mongodb', github: 'doorkeeper-gem/doorkeeper-mongodb'
gem 'doorkeeper', '~> 3.1.0'
gem 'doorkeeper-grants_assertion', github: "doorkeeper-gem/doorkeeper-
grants_assertion", :ref => 'f4391f2f07d96845db0d9dd6889f58d4bd4d23bb'