Inconsistent error message in ArgumentError exception

[eksperimental]

Environment

• Elixir & Erlang/OTP versions (elixir --version): OTP 24, Affects Elixir versions v1.12, v1.13 and main.
• Operating system: Linux

Current behavior

I started to notice that in some situation the same code would raise with different errors message.
I isolated the case to this:

defmodule DebugTest do
  use ExUnit.Case

  test "debug" do
    fun1 = fn(string) ->
      try do
        Atom.to_string(string)
      rescue
        exception -> {exception, __STACKTRACE__}
      end
    end

    fun2 = fn() ->
      try do
        Atom.to_string("Foo")
      rescue
        exception -> {exception, __STACKTRACE__}
      end
    end

    {exception1, stacktrace1} = fun1.("Foo")
    {exception2, stacktrace2} = fun2.()

    IO.inspect {:stacktrace1, stacktrace1}
    IO.inspect {:stacktrace2, stacktrace2}

    assert exception1 == exception2
  end
end

  1) test debug (DebugTest)
     test/elixir/debug2_test.exs:4
     Assertion with == failed
     code:  assert exception1 == exception2
     left:  %ArgumentError{__exception__: true, message: "errors were found at the given arguments:\n\n  * 1st argument: not an atom\n"}
     right: %ArgumentError{__exception__: true, message: "argument error"}
     stacktrace:
       test/elixir/debug2_test.exs:27: (test)

After searching for the this bug, with a git bisect running a TEST_FILES=debug2_test.exs make test_stdlib command, told me that it was 251413a (Adopt EEP 54) that introduced it.

fun1 in the test above, works as expected, but fun2 is missing the first entry in the stacktrace which holds the extra information,
in this example. {:erlang, :atom_to_binary, ["Foo", :utf8], [error_info: %{module: :erl_erts_errors}], making Exception.normalize/2 to give different messages.
I ported the two anonymous functions to Erlang, and checked the stacktraces are is identical, so we may probably rule out that this is happening on the Elixir side.

Eshell V12.1.2  (abort with ^G)
1>    Fn1 = fun() -> 
1>       try
1>          atom_to_binary(11111)
1>       catch
1>          error:Error:Stacktrace ->
1>             erlang:display({Error, Stacktrace})
1>       end
1>    end.
#Fun<erl_eval.45.65746770>
2>    Fn1().
{badarg,[{erlang,atom_to_binary,[11111],[{error_info,#{module=>erl_erts_errors}}]},{erl_eval,do_apply,6,[{file,"erl_eval.erl"},{line,689}]},{erl_eval,try_clauses,8,[{file,"erl_eval.erl"},{line,919}]},{shell,exprs,7,[{file,"shell.erl"},{line,686}]},{shell,eval_exprs,7,[{file,"shell.erl"},{line,642}]},{shell,eval_loop,3,[{file,"shell.erl"},{line,627}]}]}
true
3> 
3>    Fn2 = fun(Binary) -> 
3>       try
3>          atom_to_binary(Binary)
3>       catch
3>          error:Error:Stacktrace ->
3>             erlang:display({Error, Stacktrace})
3>       end
3>     end.
#Fun<erl_eval.44.65746770>
4>    Fn2(22222).
{badarg,[{erlang,atom_to_binary,[22222],[{error_info,#{module=>erl_erts_errors}}]},{erl_eval,do_apply,6,[{file,"erl_eval.erl"},{line,689}]},{erl_eval,try_clauses,8,[{file,"erl_eval.erl"},{line,919}]},{shell,exprs,7,[{file,"shell.erl"},{line,686}]},{shell,eval_exprs,7,[{file,"shell.erl"},{line,642}]},{shell,eval_loop,3,[{file,"shell.erl"},{line,627}]}]}
true

Expected behavior

It should be consistent

[eksperimental]

Hint: it seems to not give extra information when Elixir warns about that the function will fail.

warning: the call to :erlang.atom_to_binary/2 will fail with ArgumentError

[josevalim]

Yes, the Erlang compiler replaces the failing call by a simple error(badarg). I will raise the discussion in their issues tracker but they may keep things as is. Thanks for the report!

[josevalim]

Btw, don't compare code in shell with code from modules. The code in the shell is always evaluated and may behave slightly different (as in this case).

[eksperimental]

Btw, don't compare code in shell with code from modules. The code in the shell is always evaluated and may behave slightly different (as in this case).

my bad. I noticed this in IEx, the issue did not happen.
Thank you,

[josevalim]

erlang/otp#5440

[eksperimental]

I correct the comment about the Erlang code.
It does happen in Erlang

-module(b).
-export([fn1/0, fn2/1]).

fn1() -> 
   try
      atom_to_binary(11111)
   catch
      error:Error:Stacktrace ->
         erlang:display({Error, Stacktrace})
  end.

fn2(Arg) -> 
  try
    atom_to_binary(Arg)
  catch
    error:Error:Stacktrace ->
       erlang:display({Error, Stacktrace})
  end.

Eshell V12.1.2  (abort with ^G)
1> c('b'). 
b.erl:6:7: Warning: the call to atom_to_binary/1 will fail with a 'badarg' exception
%    6|       atom_to_binary(11111)
%     |       ^

{ok,b}
2> b:fn1().
{badarg,[{b,fn1,0,[{file,"b.erl"},{line,6}]},{erl_eval,do_apply,6,[{file,"erl_eval.erl"},{line,689}]},{shell,exprs,7,[{file,"shell.erl"},{line,686}]},{shell,eval_exprs,7,[{file,"shell.erl"},{line,642}]},{shell,eval_loop,3,[{file,"shell.erl"},{line,627}]}]}
true
3> b:fn2(222222).
{badarg,[{erlang,atom_to_binary,[222222],[{error_info,#{module=>erl_erts_errors}}]},{b,fn2,1,[{file,"b.erl"},{line,14}]},{erl_eval,do_apply,6,[{file,"erl_eval.erl"},{line,689}]},{shell,exprs,7,[{file,"shell.erl"},{line,686}]},{shell,eval_exprs,7,[{file,"shell.erl"},{line,642}]},{shell,eval_loop,3,[{file,"shell.erl"},{line,627}]}]}
true

[eksperimental]

Already fixed in OTP master, I will be out in the v24.2 release.
erlang/otp#5441

Thank you for reporting it @josevalim