Jump.CredoChecks.AvoidFunctionLevelElse (Jump.CredoChecks v0.4.0)

Basics

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

Explanation

Ensures that else is not used at the top-level of def/defp function bodies.

Elixir allows else at the function level because the function body acts as an implicit try. However, this is almost always a mistake from a botched refactor—e.g., removing a with block but leaving its else clause behind. The code will compile without warnings, but behaves unexpectedly (raising TryClauseError if no clause matches).

# ❌ Bad — function-level else
def foo(bar) do
  something(bar)
else
  {:error, reason} -> handle_error(reason)
end

# Good — use with/else or case instead
def foo(bar) do
  with {:ok, result} <- something(bar) do
    result
  else
    {:error, reason} -> handle_error(reason)
  end
end

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.