Credo.Check.Readability.WithCustomTaggedTuple (Credo v1.5.2) View Source

This check has a base priority of low and works with any version of Elixir.

Explanation

Avoid using custom tags for error reporting from with macros.

This code injects placeholder tags such as :resource and :authz for the purpose of error reporting.

with {:resource, {:ok, resource}} <- {:resource, Resource.fetch(user)},
     {:authz, :ok} <- {:authz, Resource.authorize(resource, user)} do
  do_something_with(resource)
else
  {:resource, _} -> {:error, :not_found}
  {:authz, _} -> {:error, :unauthorized}
end

Instead, extract each validation into a separate helper function which returns error information immediately:

defp find_resource(user) do
  with :error <- Resource.fetch(user), do: {:error, :not_found}
end

defp authorize(resource, user) do
  with :error <- Resource.authorize(resource, user), do: {:error, :unauthorized}
end

At this point, the validation chain in with becomes clearer and easier to understand:

with {:ok, resource} <- find_resource(user),
     :ok <- authorize(resource, user),
     do: do_something(user)

Like all Readability issues, this one is not a technical concern. But you can improve the odds of others reading and liking your code by making it easier to follow.

Configuration parameters

There are no specific parameters for this check.

Like with all checks, general params can be applied.

Parameters can be configured via the .credo.exs config file.