Pipeline module not compiled at schema compilation time

[jdewar]

I ran into the error described here: #1331 (comment) sometime ago and used the unreleased commit (ref: 3d0823bd71c2ebb94357a5588c723e053de8c66a) to fix my compilation problem, but the problem has returned.

== Compilation error in file lib/sga/frontend_schema.ex ==
** (ArgumentError) could not load module SGA.Pipeline.PublicFieldVisibility due to reason :nofile
    (elixir 1.17.2) lib/code.ex:1837: Code.ensure_loaded!/1
    (absinthe 1.7.8) lib/absinthe/schema.ex:382: anonymous fn/3 in Absinthe.Schema.apply_modifiers/3
    (elixir 1.17.2) lib/enum.ex:2531: Enum."-reduce/3-lists^foldl/2-0-"/3
    (absinthe 1.7.8) lib/absinthe/schema.ex:405: Absinthe.Schema.__after_compile__/2
    (stdlib 5.2) lists.erl:1594: :lists.foldl/3

Removing _build fixes it at the time, but it has recurred 3 times across 2 different developers in the past few weeks. Here is the pipeline definition and how it is used, in case I'm 'holding it wrong':

---

public_field_visibility.ex:

defmodule SGA.Pipeline.PublicFieldVisibility do
  alias Absinthe.{Blueprint, Phase, Pipeline}

  # Add this module to the pipeline of phases
  # to run on the schema
  def pipeline(pipeline) do
    Pipeline.insert_after(pipeline, Phase.Schema.TypeImports, __MODULE__)
  end

  # Here's the blueprint of the schema, let's do whatever we want with it.
  def run(%Blueprint{} = blueprint, _) do
    blueprint =
      update_in(
        blueprint,
        [
          Access.key!(:schema_definitions),
          Access.all(),
          Access.key!(:type_definitions),
          Access.all()
        ],
        &update_type_def/1
      )

    {:ok, blueprint}
  end

  defp update_type_def(%Absinthe.Type.Object{fields: type_fields} = type_def) do
    public_fields = Absinthe.Type.meta(type_def, :public_fields) || []
    public_fields = [:id | public_fields]
    filtered_fields = filter_fields(public_fields, type_fields)

    %{type_def | fields: filtered_fields}
  end

  defp update_type_def(type_def), do: type_def

  # we probably want to whitelist certain fields (specifically Relay fields like pageInfo { hasNextPage etc... })
  defp filter_fields(public_fields, type_def_fields) do
    Enum.filter(type_def_fields, &(&1.identifier in public_fields))
  end
end

frontend_schema.ex:

use Absinthe.Schema
use Absinthe.Relay.Schema, :modern
@pipeline_modifier SGA.Pipeline.PublicFieldVisibility

import_types ...

router.ex:

forward("/graphql", Absinthe.Plug,
  schema: SGA.FrontendSchema,
  before_send: {SGA.Context.Frontend, :before_send}
)

---

Since originally fixing the problem ancillary things have changed in the codebase, like Elixir version updated to 1.17.2, so I am now using the most recent commit, {:absinthe, github: "absinthe-graphql/absinthe", ref: "d28ebb4fdb16c195a41259ea12552800a695df42", override: true}, but updating absinthe did not make the error go away.