Unknown validator: 'ForbidChangingValidator' - ruby-on-rails

Question

I spend few hours trying to find solution of my problem, but lost any hope to understood what i am done wrong.
Rails 4.2.6
my model:
app/models/component.rb
class Component < ActiveRecord::Base
validates :name, presence: true,
uniqueness: true,
forbid_changing: true #TODO [VS] Fix custom validator autoload
validates :label, presence: true,
uniqueness: true
end
my validator:
class ForbidChangingValidator < ActiveModel::EachValidator
  def validate_each(record, attribute, value)
if record.send "#{attribute}_changed?".to_sym
record.errors[attribute] << options[:message] || t(:changing_forbidden)
end
  end
end
when try reload the page i got error:
Unknown validator: 'ForbidChangingValidator'
ArgumentError - Unknown validator: 'ForbidChangingValidator':
activemodel (4.2.6) lib/active_model/validations/validates.rb:120:in `rescue in block in validates'
activemodel (4.2.6) lib/active_model/validations/validates.rb:117:in `block in validates'
activemodel (4.2.6) lib/active_model/validations/validates.rb:113:in `validates'
app/models/component.rb:6:in `<class:Component>'
app/models/component.rb:1:in `<top (required)>'
activesupport (4.2.6) lib/active_support/dependencies.rb:457:in `block in load_file'
activesupport (4.2.6) lib/active_support/dependencies.rb:647:in `new_constants_in'
activesupport (4.2.6) lib/active_support/dependencies.rb:456:in `load_file'
activesupport (4.2.6) lib/active_support/dependencies.rb:354:in `require_or_load'
activesupport (4.2.6) lib/active_support/dependencies.rb:494:in `load_missing_constant'
activesupport (4.2.6) lib/active_support/dependencies.rb:184:in `const_missing'
activesupport (4.2.6) lib/active_support/inflector/methods.rb:261:in `block in constantize'
activesupport (4.2.6) lib/active_support/inflector/methods.rb:259:in `constantize'
activesupport (4.2.6) lib/active_support/core_ext/string/inflections.rb:66:in `constantize'
repositor (0.6.0) lib/repositor/active_record.rb:6:in `initialize'
but when i am trying to call this validator from console i got:
!! #<ArgumentError: A copy of Component has been removed from the module tree but is still active!>
I found a lot of messages about thig issue, but can't to resolve mine.
Please, help somebody....

Answer 1

I found the issue. It's about naming policy. It strange ways rails try inflect the validator name.
I renamed my validator to ForbidChangesValidator and file also.
Everything goes great.
Thx all for attention.

Answer 2

Custom validations using using ActiveModel::EachValidator need to be declared in the root namespace or "core" autoload paths (however you want to define these directories).
For example:
(YES means will work and NO means won't work)
app/validations => YES since it is a new dir off of app/ it qualifies for root namespace
app/models => YES since it is a core directory
app/models/concerns => YES since it is a core directory
app/models/validations => NO Requires name spacing since it is a child directory off a core one.

Answer 3

Restarting the server fixed the issue for me, since everything else was right in place

Answer 4

Make sure you defined ForbidChangingValidator at app/validators/forbid_changing_validator.rb and add the configuration to:
config/application.rb
# add custom validators path
config.autoload_paths += %W["#{config.root}/app/validators/"]