Unknown validator: 'ContentTypeValidator' error

[SamihaFansur]

I get a Unknown validator: 'ContentTypeValidator' error on rails 6 when I try to validate my pdf files which are attached as a has_many _attached attachment.

validates :files, content_type: {in: 'application/pdf', message: 'Please upload .pdf files only'}

[MateoLa]

Try adding to your .gemspec file: spec.add_dependency "active_storage_validations"

Then: require "active_storage_validations"

[isabel-anastasiadis-boost]

We were getting a similar issue initially and realised we'd put the gem in the :test group instead of everywhere

[Mth0158]

@SamihaFansur, @isabel-anastasiadis-boost could you give us a bit more context on this issue so we can investigate it?

[isabel-anastasiadis-boost]

My issue was just user error - gem wasn't added to the right group :)

[Mth0158]

@isabel-anastasiadis-boost alright, issue solved then :) thank you!