Bylaw.Credo.Check.Elixir.WithElseClause (bylaw_credo v0.4.0)

Basics

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

Explanation

Prefer adding an explicit else clause to every with expression.

An explicit else clause makes the failure contract visible beside the successful path and gives callers a deliberate place to normalize errors. Without it, a non-matching result leaks out according to with's implicit behavior and is easier to overlook during review.

Examples

Avoid:

  with {:ok, user} <- fetch_user(id) do
    {:ok, user.name}
  end

Prefer:

  with {:ok, user} <- fetch_user(id) do
    {:ok, user.name}
  else
    {:error, error} -> {:error, error}
  end

Notes

This check uses static AST analysis, so it favors clear source-level patterns over runtime behavior.

Options

This check has no check-specific options. Configure it with an empty option list.

Usage

Add this check to Credo's checks: list in .credo.exs:

%{
  configs: [
    %{
      name: "default",
      checks: [
        {Bylaw.Credo.Check.Elixir.WithElseClause, []}
      ]
    }
  ]
}

Check-Specific Parameters

There are no specific parameters for this check.

General Parameters

Like with all checks, general params can be applied.

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