If anyone ever runs into that problem, you probably haven’t implemented consume_upload_entries/3 in your lv.

It’s not obvious as long if you do not read the documentation carefully, where everything is totally fine explained.

Consumes the uploaded entries.
Raises when there are still entries in progress. Typically called when submitting a form to handle the uploaded entries alongside the form data. For form submissions, it is guaranteed that all entries have completed before the submit event is invoked. Once entries are consumed, they are removed from the upload.

You need to invoke that function to clean up the uploaded entries… this function incorporates the flushing and clean up and everything.

have fun… there is always a solution to everything…

And if you use the option auto_upload: true then sth like this does the trick:

@impl Phoenix.LiveView
def handle_event("cancel_upload", %{"ref" => ref}, socket) do
  socket = socket |> cancel_upload(:files, ref)

  case socket.assigns.uploads.files.entries |> Enum.all?(& &1.done?) do
    true ->
      consume_uploaded_entries(socket, :files, fn _res, _entryy -> {:ok, nil} end)

      {:noreply,
        socket
        |> assign(:all_uploads_done, true)
        |> put_flash(:info, "All files uploaded")}

    false ->
      {:noreply, socket}
  end
end