devise_token_auth: wrong number of arguments (given 0, expected 1) during RegistrationsController#create

Question

I'm using devise_token_auth to set up authentication for an API-only Rails app. I am testing the registration creation using httpie at the command line with the following command:

http POST :3000/auth 'email=username@email.com' 'password=password' 'password_confirmation=password'

The response is the full HTML output of the error page, and the error within is wrong number of arguments (given 0, expected 1). The offending action is DeviseTokenAuth::RegistrationsController#create.

Thanks in advance for any guidance. Code is here: https://github.com/jraczak/flow-api

Devise is applied to the User model: here

Routes is here

Answer 1

Summarising the chat discussion with an answer...

Just remove has_secure_password in https://github.com/jraczak/flow-api/blob/master/app/models/user.rb and :password_digest from validates_presence_of :name, :email, :password_digest...Devise already does that

I see that you already added encrypted_password column in your schema (https://github.com/jraczak/flow-api/blob/master/db/schema.rb) ...In that case remove the password_digest column from the table...It would work

rails g migration RemovePwdDigest

class RemovePwdDigest < ActiveRecord::Migration 
  def change 
    remove_column :users, :password_digest 
  end 
end

What might have gone wrong even after removing has_secure_password and validation:

https://github.com/plataformatec/devise/blob/ee01bac8b0b828b3da0d79c46115ba65c433d6c8/lib/devise/models/database_authenticatable.rb#L45

If you see this line, devise tries to call it's internal password_digest method while setting a new password or wherever you use password= method. But, as you already have a db column with name similar to the method (password_digest column), it is calling that instead of devise internal method. So, you are facing an error. (I may be wrong, this alone seems to be suspicious)