Erlang OTP 23.0-rc2 is available for testing

[John Högberg]

Thanks for pointing this out, I'm looking into it.

/John

-----Original Message-----
From: erlang-questions <erlang-questions-bounces@REDACTED> On Behalf Of Kostis Sagonas
Sent: Thursday, March 26, 2020 15:30
To: erlang-questions@REDACTED
Subject: Re: Erlang OTP 23.0-rc2 is available for testing

On 3/25/20 3:24 PM, Kenneth Lundin wrote:
> 
>     OTP 23 Release Candidate 2
> 
> This is the second of three planned release candidates before the OTP 
> 23 release.
> The intention with this release is to get feedback from our users. All 
> feedback is welcome, even if it is only to say that it works for you.
> 

Hmmm,,.  erlang:apply/3 seems to be broken, for me at least.

I had noticed some failures of PropEr
(https://github.com/proper-testing/proper) long ago on the 'master' 
branch, but decided to investigate them yesterday and today.

Half day of debugging has produced the following (minimized) test case.

======================
-module(bug23).
-export([test/0]).

test() ->
     symb_walk({call,lists,reverse,[[1,2,3]]}, fun erlang:apply/3).

symb_walk({call,Mod,Fun,Args}, HandleCall) ->
     SymbWalk = fun(X) -> symb_walk(X, HandleCall) end,
     HandledArgs = [SymbWalk(A) || A <- Args],
     HandleCall(Mod, Fun, HandledArgs);
symb_walk(SymbTerm, HandleCall) ->
     SymbWalk = fun(X) -> symb_walk(X, HandleCall) end,
     do_symb_walk_gen(SymbWalk, SymbTerm).

do_symb_walk_gen(SymbWalk, SymbTerm) when is_list(SymbTerm) ->
     safe_map_tr(SymbWalk, SymbTerm, []); do_symb_walk_gen(_, SymbTerm) ->
     SymbTerm.

safe_map_tr(_Fun, [], AccList) ->
     lists:reverse(AccList);
safe_map_tr(Fun, [Head | Tail], AccList) ->
     safe_map_tr(Fun, Tail, [Fun(Head) | AccList]).
======================

Works OK on 22.x and prior but crashes with

42> bug23:test().
** exception error: bad argument
      in function  apply/3
         called as apply(lists,reverse,[[1,2,3]])

on 23.0-rc2.


Kostis