My tests started randomly failing in GitLab one day. I say randomly because re-running the tests for previously passing code, now has them failing. I was able to reproduce on my laptop by deleting all my deps and _build folders, deleting all my docker volumes/images/etc, and rebuilding everything from blank.

I’m getting this compilation error:

== Compilation error in file lib/horse_racing_nation_web/entries/views/picks_view.ex ==
** (CompileError) lib/horse_racing_nation_web/entries/views/picks_view.ex:2: module HorseRacingNationWeb.Entries.Router.Helpers is not loaded and could not be found
    expanding macro: HorseRacingNationWeb.Entries.__using__/1
    lib/horse_racing_nation_web/entries/views/picks_view.ex:2: HorseRacingNationWeb.Entries.PicksView (module)
    (elixir 1.11.4) expanding macro: Kernel.use/2
    lib/horse_racing_nation_web/entries/views/picks_view.ex:2: HorseRacingNationWeb.Entries.PicksView (module)

The view file in the error:

lib/horse_racing_nation_web/entries/views/picks_view.ex

defmodule HorseRacingNationWeb.Entries.PicksView do
  use HorseRacingNationWeb.Entries, :view

  <snip>
end

I think this file is pretty much what Phoenix generates.

lib/horse_racing_nation_web/entries.ex

defmodule HorseRacingNationWeb.Entries do
  def controller do
    quote do
      use Phoenix.Controller, namespace: HorseRacingNationWeb.Entries
      import Plug.Conn
      import HorseRacingNationWeb.Entries.Router.Helpers
      import HorseRacingNationWeb.Gettext
    end
  end

  def view do
    quote do
      use Phoenix.View,
        root: "lib/horse_racing_nation_web/entries/templates",
        namespace: HorseRacingNationWeb.Entries

      # Import convenience functions from controllers
      import Phoenix.Controller, only: [get_flash: 2, view_module: 1]

      # Use all HTML functionality (forms, tags, etc)
      use Phoenix.HTML

      import HorseRacingNationWeb.Entries.Router.Helpers
      import HorseRacingNationWeb.Entries.ErrorHelpers
      import HorseRacingNationWeb.Gettext
    end
  end

  def router do
    quote do
      use Phoenix.Router
      import Plug.Conn
      import Phoenix.Controller
    end
  end

  def channel do
    quote do
      use Phoenix.Channel
      import HorseRacingNationWeb.Gettext
    end
  end

  @doc """
  When used, dispatch to the appropriate controller/view/etc.
  """
  defmacro __using__(which) when is_atom(which) do
    apply(__MODULE__, which, [])
  end
end

My router.
lib/horse_racing_nation_web/entries/router.ex

defmodule HorseRacingNationWeb.Entries.Router do
  use HorseRacingNationWeb.Entries, :router
  use Honeybadger.Plug

  pipeline :browser do
    plug(:accepts, ["html"])

    <snip>
  end

  pipeline :api do
    plug(:accepts, ["json"])

    <snip>
  end

  scope "/api", HorseRacingNationWeb.Entries, as: "api" do
    pipe_through(:api)

    <snip>
  end

  scope "/", HorseRacingNationWeb.Entries do
    pipe_through(:browser)

    <snip>
  end
end

I thought maybe there was some sort of circular dependency because both HorseRacingNationWeb.Entries.PicksView and HorseRacingNationWeb.Entries.Router are using HorseRacingNationWeb.Entries, so I tried to inline the use in the router. That didn’t help.

The code all seems to be correct to me, and I’ve been banging my head against a wall for too long. I’m guessing the router helpers aren’t being generated, but I don’t know why. Can someone help?