Intermittent: `(EXIT) shutdown: failed to start child: ConCache.LockSupervisor`

[krisleech]

When I run my tests or start iex I sometimes get the following error:

** (Mix) Could not start application export: Export.Application.start(:normal, []) returned an error: shutdown: failed to start child: ConCache
    ** (EXIT) shutdown: failed to start child: ConCache.LockSupervisor
        ** (EXIT) an exception was raised:
            ** (ArgumentError) unknown registry: ConCache
                (elixir 1.17.1) lib/registry.ex:1400: Registry.key_info!/1
                (elixir 1.17.1) lib/registry.ex:237: Registry.whereis_name/2
                (stdlib 5.2.3) gen.erl:107: :gen.start/6
                (stdlib 5.2.3) supervisor.erl:420: :supervisor.do_start_child_i/3
                (stdlib 5.2.3) supervisor.erl:406: :supervisor.do_start_child/2
                (stdlib 5.2.3) supervisor.erl:390: anonymous fn/3 in :supervisor.start_children/2
                (stdlib 5.2.3) supervisor.erl:1258: :supervisor.children_map/4
                (stdlib 5.2.3) supervisor.erl:350: :supervisor.init_children/2

It is intermittent, and typically if I run the tests again there is no error.

This is how is setup:

defmodule Export.Application do
  @moduledoc false

  use Application

  @impl true
  def start(_type, _args) do
    children = [
      Export.Scheduler,
      {
        ConCache,
        [
          name: :payment_method_cache,
          ttl_check_interval: :timer.seconds(5),
          global_ttl: :timer.minutes(10),
          touch_on_read: true
        ]
      }
    ]

    opts = [strategy: :one_for_one, name: Export.Supervisor]
    Supervisor.start_link(children, opts)
  end
end

defmodule Export.MixProject do
  use Mix.Project

  # ...

  def application do
    [
      extra_applications: [:logger, :con_cache],
      mod: {Export.Application, []}
    ]
  end
end

As per the docs I tried to add :con_cache to applications but I got a warning, I think extra_applications is now correct.

Any thoughts much appreciated ❤️

I noticed I also sometimes see: ** (Mix) Could not start application con_cache: could not find application file: con_cache.app, again this goes away on retry.

It also never seems to happen on CI.