Fix warning when used in elixir 1.16

[JonathanTron]

Elixir 1.16.0 String.slice/2 started warning about the range having negative steps:

iex(1)> String.slice("demo", 1..-1)
warning: negative steps are not supported in String.slice/2, pass 1..-1//1 instead
  (elixir 1.16.0) lib/string.ex:2368: String.slice/2
  (elixir 1.16.0) src/elixir.erl:405: :elixir.eval_external_handler/3
  (stdlib 5.2) erl_eval.erl:750: :erl_eval.do_apply/7
  (elixir 1.16.0) src/elixir.erl:378: :elixir.eval_forms/4
  (elixir 1.16.0) lib/module/parallel_checker.ex:112: Module.ParallelChecker.verify/1
  (iex 1.16.0) lib/iex/evaluator.ex:331: IEx.Evaluator.eval_and_inspect/3
  (iex 1.16.0) lib/iex/evaluator.ex:305: IEx.Evaluator.eval_and_inspect_parsed/3
  (iex 1.16.0) lib/iex/evaluator.ex:294: IEx.Evaluator.parse_eval_inspect/4
  (iex 1.16.0) lib/iex/evaluator.ex:187: IEx.Evaluator.loop/1
  (iex 1.16.0) lib/iex/evaluator.ex:32: IEx.Evaluator.init/5
  (stdlib 5.2) proc_lib.erl:241: :proc_lib.init_p_do_apply/3

This fixes it.

[nathany-copia]

Thanks @JonathanTron. I'm going to use your branch for now.

[TheFirstAvenger]

@JonathanTron thank you for this fix! Looking forward to it being merged into main.

[ddengler]

Does this break with the set elixir: "~> 1.2", compatibility? Is this even correct or should this also be changed? Could find //step syntax only in elixir 1.12 and up on a quick glance - which is also the oldest version with active security patches

[JonathanTron]

Hi @ddengler, from a try to run on elixir 1.2:

# mix deps.get
** (Mix.Config.LoadError) could not load config config/config.exs
    ** (CompileError) config/config.exs:3: module Config is not loaded and could not be found
    (elixir) lib/code.ex:168: Code.eval_string/3
    (mix) lib/mix/config.ex:150: Mix.Config.read!/1
    (mix) lib/mix/tasks/loadconfig.ex:36: Mix.Tasks.Loadconfig.load/1
    (mix) lib/mix/tasks/loadconfig.ex:27: Mix.Tasks.Loadconfig.run/1

So I'm not sure the compatibility with 1.2 is so important :), I think changing it to "~> 1.12" is for the best.

[nathany-copia]

How many versions back do you want/need to support?

Unfortunately I don't see in the release notes or the documentation for slice and Range when the newer syntax was first supported: https://github.com/elixir-lang/elixir/releases/tag/v1.16.0

As for Config:

the Config module in Elixir was introduced in v1.9 as a replacement to use Mix.Config, which was specific to Mix and has been deprecated.

So 1.9 may be worth testing as a minimum?

Personally I'd only support the last 2 or 3 minor releases (e.g. 1.16.x, 1.15.x, 1.14.x).

[ddengler]

@JonathanTron @nathany-copia I agree. We only use 1.15 and 1.16. – as this seems to be a basic (in many toolboxes) dependency, I think this should be addressed by changing the minimum version to the earliest working release.

[paulo-silva]

Hey guys, is something holding this PR to be merged?

[rhblind]

Would also love to see this merged :)

[ViseLuca]

@rubemz can you helps us merging this one?

[nathany-copia]

It looks like #62 makes the same change and was merged.

[JonathanTron]

Thanks @nathany-copia , I didn't see it yet. I'm closing this one then.