Mix Unused

Mix compiler tracer for detecting unused public functions.

Installation

def deps do
  [
    {:mix_unused, "~> 0.3.0"}
  ]
end

The docs can be found at https://hexdocs.pm/mix_unused.

Usage

After installation you need to add :unused as a compiler to the list of Mix compilers:

defmodule MySystem.MixProject do
  use Mix.Project

  def project do
    [
      compilers: [:unused] ++ Mix.compilers(),
      # In case of Phoenix projects you need to add it to the list
      # compilers: [:unused, :phoenix, :gettext] ++ Mix.compilers()
      # ...
      #
      # If you want to only run it in the dev environment you could do
      # it by using `compilers: compilers(Mix.env()) ++ Mix.compilers()`
      # instead and then returning the right compilers per environment.
    ]
  end

  # ...
end

Then you just need to run mix compile or mix compile --force as usual and unused hints will be added to the end of the output.

Warning

This isn't perfect solution and this will not find dynamic calls in form of:

apply(mod, func, args)

So this mean that, for example, if you have custom child_spec/1 definition then mix unused can return such function as unused even when you are using that indirectly in your supervisor.

Configuration

You can define used functions by adding mfa in unused: [ignored: [⋯]] in your project configuration:

def project do
  [
    # ⋯
    unused: [
      ignore: [
        {MyApp.Foo, :child_spec, 1}
      ]
    ],
    # ⋯
  ]
end

Copyright and License

Copyright © 2021 by Łukasz Niemier

This work is free. You can redistribute it and/or modify it under the terms of the MIT License. See the LICENSE file for more details.