Dializer and with statements

I’m trying to run dialyzer against my code base. I am using with and it’s giving me pattern match errors:

And I get:

The pattern
{:ok, _widget}

can never match the type
{:error, binary()}

I get the same issues CONSTANTLY when I use with and else. I worked around it by just making my else branch in full be:

else err -> handle_controller_errors(err)

I don’t really like it, and occasionally I have to add specialty handlers for failures so I end up encoding those into case’s instead inside the with, it’s all fairly ugly and I really need to make a new ‘with’… >.>

EDIT: Most of my control flow uses the exceptional library, but some modules I used with instead and got all those issues, I didn’t expand it out. I need to try the ok library fully sometime in a module to see how its error handling fares…

It’s not solving the dyalizer problem but…

  • It seems your code is missing one end to close run function
  def run(input) do
    with {:ok, widget} <- process_widget(input) do
      do_something_with_widget(widget) #noop
      {:error, reason} ->
        #something with reason
  end # <- this end is missing in your code
  • You do not use error, it would be better to use _error in that case
      error ->
        {:error, "Received error"}
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