Receiving `:garbage_collect` in tests from Phoenix.LiveViewTest.UploadClient

Hi, I’m trying to test a live_file_input and everything seems to work, but I’m getting a weird error, specifically:

[error] Phoenix.LiveViewTest.UploadClient #PID<0.776.0> received unexpected message in handle_info/2: :garbage_collect

If I blow away my _build, I also get this error on the first run (but not subsequent runs):

[error] Phoenix.LiveViewTest.UploadClient #PID<0.7054.0> received unexpected message in handle_info/2: {:socket_close, #PID<0.7055.0>, {:shutdown, :closed}}

My form is simply the live_file_input along with a submit button. The error happens when submitting the form (render_submit). However, the test will continue and complete successfully.

How would I go about debugging this or getting rid of the error? Currently using version 0.15.4.

The only issue I could find that’s remotely related is the following, but that seems to be taken care of already:

https://github.com/phoenixframework/phoenix_live_view/issues/1269

The Test

defmodule MyAppWeb.Settings.ProfileLiveTest do
  use MyAppWeb.ConnCase

  import Phoenix.LiveViewTest

  setup :register_and_log_in_user

  test "GET /settings/profile/update_avatar", %{conn: conn} do
    {:ok, index_live, html} = live(conn, Routes.settings_profile_path(conn, :index))
    assert html =~ "gravatar"
    refute html =~ "Progress:"

    avatar = file_input(index_live, "#change-avatar-form", :avatar, [%{
      last_modified: 1_594_171_879_000,
      name: "elixir.png",
      content: File.read!("test/support/files/elixir.png"),
      size: 8_290,
      type: "image/png"
    }])

    assert render_upload(avatar, "elixir.png") =~ "Progress:"
    assert %{"elixir.png" => _channel_pid} = Phoenix.LiveViewTest.UploadClient.channel_pids(avatar)

    submitted_form =
      index_live
      |> form("#change-avatar-form")
      |> render_submit()

    refute submitted_form =~ "gravatar"
  end
end

Test Output (clean)

➜  mix test

21:59:21.548 [error] Phoenix.LiveViewTest.UploadClient #PID<0.7054.0> received unexpected message in handle_info/2: :garbage_collect

21:59:21.569 [error] Phoenix.LiveViewTest.UploadClient #PID<0.7054.0> received unexpected message in handle_info/2: {:socket_close, #PID<0.7055.0>, {:shutdown, :closed}}

.

Finished in 0.6 seconds
1 test, 0 failures

Randomized with seed 445784

Test Output

➜  mix test

21:44:48.667 [error] Phoenix.LiveViewTest.UploadClient #PID<0.776.0> received unexpected message in handle_info/2: :garbage_collect

.

Finished in 0.8 seconds
1 test, 0 failures

Randomized with seed 485533