FunctionClauseError when starting newly cloned elixir-koans

[m3co-code]

This is my absolute first contact with Elixir: so I have no clue what I'm doing! I freshly installed Erlang and Elixir on Ubuntu, cloned this nice koan project, installed the mix dependencies and started to meditate. But I get an error right away. Here the list of things I have installed. Please let me know if I can provide more information!

$ elixir -v
Erlang/OTP 23 [erts-11.0.1] [source] [64-bit] [smp:8:8] [ds:8:8:10] [async-threads:1] [hipe]

Elixir 1.10.3 (compiled with Erlang/OTP 21)

$ mix -v
Erlang/OTP 23 [erts-11.0.1] [source] [64-bit] [smp:8:8] [ds:8:8:10] [async-threads:1] [hipe]

Mix 1.10.3 (compiled with Erlang/OTP 21)

$ mix deps.get
Resolving Hex dependencies...
Dependency resolution completed:
Unchanged:
  file_system 0.2.2
All dependencies are up to date

$ mix meditate
15:56:28.380 [error] Process #PID<0.459.0> raised an exception
** (FunctionClauseError) no function clause matching in Execute.extract_file_and_line/1
    (elixir_koans 0.0.1) lib/execute.ex:53: Execute.extract_file_and_line(nil)
    (elixir_koans 0.0.1) lib/execute.ex:46: Execute.expand/2
    (elixir_koans 0.0.1) lib/execute.ex:35: Execute.exec/4

Thank you already for your work and the koans!

[m3co-code]

FTR: I verified whether the PR #242 would resolve the issue, as it looked related, but the result is exactly the same as before.

[rabuf]

A workaround that will let you at least run the koans, though it removes useful information, is to simply add:

defp extract_file_and_line(_), do: {:unknown, :unknown}

after the existing clause. For some reason (I'm new to Elixir so I'm not sure why) after processing the stack trace, the value spent to the extract function is nil. This probably has to do with the way stacktrace has to be called inside of a try/rescue now, but this is as far as I got.

[kknives]

I looked at it and it seems that System.stacktrace has been phased out in Elixir 1.10
So, with #251 the tests pass and a few koans I tried gave me no errors.

[kknives]

It should work now