Ash Elixir•2y ago

many_to_many exception after updating Ash

Previous version was 2.6.31. I updated to 2.11.8 today and an existing many_to_many association that I had is now raising an exception. Did something change? Here are my resources:

defmodule MyApp.Budgeting.Book do
  relationships do
    many_to_many :users, MyApp.Authentication.User do
      through MyApp.Budgeting.BookUser
      api MyApp.Authentication
      source_attribute_on_join_resource :book_id
      destination_attribute_on_join_resource :user_id
    end
  end
end

defmodule MyApp.Budgeting.Book do
  relationships do
    many_to_many :users, MyApp.Authentication.User do
      through MyApp.Budgeting.BookUser
      api MyApp.Authentication
      source_attribute_on_join_resource :book_id
      destination_attribute_on_join_resource :user_id
    end
  end
end

defmodule MyApp.Authentication.User do
  relationships do
    many_to_many :books, MyApp.Budgeting.Book do
      through MyApp.Budgeting.BookUser
      api MyApp.Budgeting
      source_attribute_on_join_resource :user_id
      destination_attribute_on_join_resource :book_id
    end
  end
end

defmodule MyApp.Authentication.User do
  relationships do
    many_to_many :books, MyApp.Budgeting.Book do
      through MyApp.Budgeting.BookUser
      api MyApp.Budgeting
      source_attribute_on_join_resource :user_id
      destination_attribute_on_join_resource :book_id
    end
  end
end

defmodule MyApp.Budgeting.BookUser do
  relationships do
    belongs_to :book, MyApp.Budgeting.Book do
      allow_nil? false
    end

    belongs_to :user, MyApp.Authentication.User do
      api MyApp.Authentication
      allow_nil? false
    end
  end
end

defmodule MyApp.Budgeting.BookUser do
  relationships do
    belongs_to :book, MyApp.Budgeting.Book do
      allow_nil? false
    end

    belongs_to :user, MyApp.Authentication.User do
      api MyApp.Authentication
      allow_nil? false
    end
  end
end

Here's the error I'm getting:

** (RuntimeError) Resource `MyApp.Budgeting.BookUser` is not accepted by api `MyApp.Authentication` for autogenerated join relationship: `:users_join_assoc`

Relationship was generated by the `many_to_many` relationship `:users`

If the `through` resource `MyApp.Budgeting.BookUser` is not accepted by the same
api as the destination resource `MyApp.Authentication.User`,
then you must define that relationship manually. To define it manually, add the following to your
relationships:

    has_many :users_join_assoc, MyApp.Budgeting.BookUser do
      # configure the relationship attributes
      ...
    end

You can use a name other than `:users_join_assoc`, but if you do, make sure to
add that to `:users`, i.e

    many_to_many :users_join_assoc, MyApp.Budgeting.BookUser do
      ...
      join_relationship_name :your_new_name
    end

** (RuntimeError) Resource `MyApp.Budgeting.BookUser` is not accepted by api `MyApp.Authentication` for autogenerated join relationship: `:users_join_assoc`

Relationship was generated by the `many_to_many` relationship `:users`

If the `through` resource `MyApp.Budgeting.BookUser` is not accepted by the same
api as the destination resource `MyApp.Authentication.User`,
then you must define that relationship manually. To define it manually, add the following to your
relationships:

    has_many :users_join_assoc, MyApp.Budgeting.BookUser do
      # configure the relationship attributes
      ...
    end

You can use a name other than `:users_join_assoc`, but if you do, make sure to
add that to `:users`, i.e

    many_to_many :users_join_assoc, MyApp.Budgeting.BookUser do
      ...
      join_relationship_name :your_new_name
    end

5 Replies

TerrybleOP•2y ago

This is working in my app in its current state. When I tried updating all of the Ash-related libraries to the latest version, I am now getting this exception

ZachDaniel•2y ago

Yes, it only causes issues if you do specific things So we added the error to prevent surprising errors from popping up in the future for you You should follow the instructions in the error

TerrybleOP•2y ago

Ah. Sorry, I was confused. So the join relationship now needs to be stated explicitly similar to Rails. Thanks for helping!

ZachDaniel•2y ago

Only in cases where the destination resource is in a different api 🙂

franckstifler•2y ago

Fell on the same issue. I went with creating another module in the different API and set migrate? false

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many_to_many exception after updating Ash

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