FieldExtension: pass extended values instead of originals to after_resolve

[swalkinshaw]

This is a follow-up after #3138 which had breaking changes for our application without a real way to work around it. This proposes a solution to make extensions dealing with extended arguments more flexible.

Field Extensions let you extend (modify) the resolver object and arguments in the resolve hook. Previously the after_resolve hook would receive the original object and arguments and not the extended ones. This was a lossy process with no way for after_resolve to access the extended values.

This changes after_resolve to receive the extended values instead. If you need access to the original non-extended values, the memo argument can be used.

Example:

class MyExtension < GraphQL::Schema::FieldExtension
  def apply(field)
    field.argument(:my_new_arg, :string, required: false)
  end

  def resolve(object:, arguments:, context:)
    next_args = arguments.dup
    next_args.delete(:my_new_arg)
    yield(object, next_args, { original_arguments: arguments })
  end

  def after_resolve(value:, context:, arguments:, memo:, **_args)
    # `arguments` => extended/modified arguments
    # `memo` => hash with `original_arguments`
  end
end

cc @jturkel what do you think?

[swalkinshaw]

Should be noted this is another breaking change after #3138 as well.

[swalkinshaw]

Oh I'll probably add a more explicit test case for this behaviour

[rmosolgo]

Should I wait for another test before merging this? I'm happy with the test coverage as-is, but also happy to wait if you want to push a proper test for this behavior.

[swalkinshaw]

😅 I completely forgot. I do want to add another test

[swalkinshaw]

Added a test

[rmosolgo]

Thanks!