Can you create circular dependancies when using `import_types`?

My absinthe schema files are growing quite significantly. It is getting hard to keep track of schema definitions.

I’d like to structure my files with relation to entities I am dealing with.

Let’s say I have two following modules

defmodule UserSchema do
  use Absinthe.Schema.Notation

  object :user do
     field :name, :string
  end
end

defmodule PostSchema do
  use Absinthe.Schema.Notation
  
  object :post do
    field :title, :string
    field :contents, :string
  end
end

I can import them into a global schema definition with import_types directive. That’s cool. But my entities are related to each other, and often the relation is circular. If we have something like this:

defmodule UserSchema do
  use Absinthe.Schema.Notation
  import_types(PostSchema)

  object :user do
     field :name, :string
     field :posts, list_of(:post)
  end
end

defmodule PostSchema do
  use Absinthe.Schema.Notation
  import_types(UserSchema)
  
  object :post do
    field :title, :string
    field :contents, :string
    field :author, :user
  end
end

This causes an infinite loop on compilation. And it does make sense.

The question is: Can I have circular dependancies on graphql type definitions? And if so, how would I accomplish this.

I know that circular resolution is f-ing hard. And I wouldn’t be surprised if such capabilities are not implemented. Honestly, it would be enough for me to even have C-like declarations that type exists, but is defined elsewhere

import_types is only needed in your schema module. It should not be used in any of the type modules (i.e. those that have use Absinthe.Schema.Notation). See also Importing Types — absinthe v1.7.0.

References in PostSchema to :user and in UserSchema to :post are resolved in compilation to ensure the types exist.

2 Likes

Thanks, that is indeed the case. For some reason I was mislead that in order for references to be resolved, they had to be imported first. I think it was one of those X is not defined in your schema that threw me off, which now seems to be unrelated.

Created a PR to no longer allow import_types and similar in the type modules to avoid this confusion.