graphql_devise: Error on rails s: uninitialized constant DeviseTokenAuth::Concerns::TokensSerialization (NameError)

Hey! we encountered the same issue in our App, but luckily it was long after the initial setup, so that helped narrow the problem. I cannot offer a definitive solution, only some hints. In our case, it was caused by an initializer referencing an ActiveRecord Model (in fact it was not even referencing the model directly, only it’s stringified name “myModel”, but the code that the related gem was calling const_get("MyModel")).

The setup

• We had an unrelated model (not the User model) called in an initializer
• This seems to cause early loading of the User model (this part is a bit unclear as why to me, probably following the dependency tree)
• Result in uninitialized constant DeviseTokenAuth::Concerns::TokensSerialization

The solution in our case

Switching the initializer to run later fixed the problem.

Code before:

MyGem.new("UnrelatedModel")

Excerpt from the Zeitwerk loading logs:

Zeitwerk@rails.main: constant DeviseTokenAuth::Concerns::User loaded from file /Users/louim/.asdf/installs/ruby/2.6.6/lib/ruby/gems/2.6.0/gems/devise_token_auth-1.1.4/app/models/devise_token_auth/concerns/user.rb
Zeitwerk@rails.main: constant GraphqlDevise::Concerns::Model loaded from file /Users/louim/.asdf/installs/ruby/2.6.6/lib/ruby/gems/2.6.0/gems/graphql_devise-0.13.4/app/models/graphql_devise/concerns/model.rb
Zeitwerk@rails.main: constant DeviseTokenAuth::Concerns::ActiveRecordSupport loaded from file /Users/louim/.asdf/installs/ruby/2.6.6/lib/ruby/gems/2.6.0/gems/devise_token_auth-1.1.4/app/models/devise_token_auth/concerns/active_record_support.rb
rails aborted!
NameError: uninitialized constant DeviseTokenAuth::Concerns::TokensSerialization
/Users/louim/work/fx-api/app/models/user.rb:8:in `include'

Code after:

Rails.configuration.to_prepare do
  MyGem.new("UnrelatedModel")
end

Excerpt from the Zeitwerk loading logs:

Zeitwerk@rails.main: constant DeviseTokenAuth::Concerns::User loaded from file /Users/louim/.asdf/installs/ruby/2.6.6/lib/ruby/gems/2.6.0/gems/devise_token_auth-1.1.4/app/models/devise_token_auth/concerns/user.rb
Zeitwerk@rails.main: constant GraphqlDevise::Concerns::Model loaded from file /Users/louim/.asdf/installs/ruby/2.6.6/lib/ruby/gems/2.6.0/gems/graphql_devise-0.13.4/app/models/graphql_devise/concerns/model.rb
Zeitwerk@rails.main: constant DeviseTokenAuth::Concerns::TokensSerialization loaded from file /Users/louim/.asdf/installs/ruby/2.6.6/lib/ruby/gems/2.6.0/gems/devise_token_auth-1.1.4/app/models/devise_token_auth/concerns/tokens_serialization.rb
Zeitwerk@rails.main: constant DeviseTokenAuth::Concerns::ActiveRecordSupport loaded from file /Users/louim/.asdf/installs/ruby/2.6.6/lib/ruby/gems/2.6.0/gems/devise_token_auth-1.1.4/app/models/devise_token_auth/concerns/active_record_support.rb
Zeitwerk@rails.main: constant DeviseTokenAuth::Concerns::UserOmniauthCallbacks loaded from file /Users/louim/.asdf/installs/ruby/2.6.6/lib/ruby/gems/2.6.0/gems/devise_token_auth-1.1.4/app/models/devise_token_auth/concerns/user_omniauth_callbacks.rb
Zeitwerk@rails.main: constant DeviseTokenAuthEmailValidator loaded from file /Users/louim/.asdf/installs/ruby/2.6.6/lib/ruby/gems/2.6.0/gems/devise_token_auth-1.1.4/app/validators/devise_token_auth_email_validator.rb
Zeitwerk@rails.main: constant User loaded from file /Users/louim/work/fx-api/app/models/user.rb

Like I said above, delaying initialization feels more of a workaround than a proper fix, but I didn’t have the time to dig down in this gem (and DTAs) to find the culprit. I hope that it can help people with the same error to narrow their problem.

Hey @namolnad, I can confirm I got the same error message on the generator about the file not found and I will look into that. But that doesn’t stop the generator to complete installation. Anyway, looks like an autoload problem with Rails, and in a weird place as it happens inside DTA’s gem code. You shouldn’t have a problem if both initializers are generated properly.

Could you please provide a repo where we can replicate this? I just created this one using your gemfiles and just disabled a couple of gems that I won’t have the time to setup. Everything works fine here and created that one from scratch. Even if you can replicate the error on that repo, that’d be awesome.