[erlang-bugs] Silly eshell history behavior

[Matthew Dempsky]

I downloaded an R12B-1 snapshot to see if this patch had been merged
yet, and was initially excited because looking over the current
group.erl, the lines match up with the + lines in my diff below, but
testing then showed my test case still fails... after first wildly
assuming it was a platform specific thing and a few hours of repeated
recompiling on every machine I have access to, I finally noticed that
my patch below is reversed (I ran "diff -u group.erl group.erl.orig"
instead of "diff -u group.erl.orig group.erl")...

So in case any Erlang developers looked at this patch and/or tried to
merge it and assumed it had already been applied, no, it has not (as
of the 20080408 snapshot I downloaded).  I'd appreciate if someone
would give feedback on this.

(patch(1) has a -R option to apply a patch in reverse for this reason.
 Alternatively, I'll repost the diff correctly generated.)

On Thu, Mar 27, 2008 at 11:38 AM, Matthew Dempsky <matthew@REDACTED> wrote:
> Run erl, type "1.", hit enter, type "2.", hit enter, press up, press
>  down, press up.
>
>  I expect at the end of this sequence for the command edit buffer to
>  contain "2.", not "1.".  Below is a patch for this.
>
>  Let me know if this breaks any intentional behavior and I will revise
>  it as necessary.
>
>
>  --- lib/kernel/src/group.erl    2008-03-27 11:34:12.000000000 -0700
>  +++ lib/kernel/src/group.erl.orig       2007-11-26 10:55:37.000000000 -0800
>  @@ -329,9 +329,9 @@ get_line1({undefined,{_A,Mode,Char},Cs,C
>         or ((Mode =:= meta_left_sq_bracket) and (Char =:= $A)) ->
>      send_drv_reqs(Drv, Rs),
>      case up_stack(Ls0) of
>  -       {none,_Ls} ->
>  +       {none,Ls} ->
>             send_drv(Drv, beep),
>  -           get_line1(edlin:edit_line(Cs, Cont), Drv, Ls0);
>  +           get_line1(edlin:edit_line(Cs, Cont), Drv, Ls);
>         {Lcs,Ls} ->
>             send_drv_reqs(Drv, edlin:erase_line(Cont)),
>             {more_chars,Ncont,Nrs} = edlin:start(edlin:prompt(Cont)),
>  @@ -346,9 +346,9 @@ get_line1({undefined,{_A,Mode,Char},_Cs,
>         or ((Mode =:= meta_left_sq_bracket) and (Char =:= $B)) ->
>      send_drv_reqs(Drv, Rs),
>      case down_stack(Ls0) of
>  -       {none,Ls} ->
>  +       {none,_Ls} ->
>             send_drv_reqs(Drv, edlin:erase_line(Cont)),
>  -           get_line1(edlin:start(edlin:prompt(Cont)), Drv, Ls);
>  +           get_line1(edlin:start(edlin:prompt(Cont)), Drv, Ls0);
>         {Lcs,Ls} ->
>             send_drv_reqs(Drv, edlin:erase_line(Cont)),
>             {more_chars,Ncont,Nrs} = edlin:start(edlin:prompt(Cont)),
>  @@ -407,17 +407,21 @@ new_stack(Ls) -> {stack,Ls,{},[]}.
>
>   up_stack({stack,[L|U],{},D}) ->
>      {L,{stack,U,L,D}};
>  +up_stack({stack,[L|U],C,D}) ->
>  +    {L,{stack,U,L,[C|D]}};
>   up_stack({stack,[],{},D}) ->
>      {none,{stack,[],{},D}};
>  -up_stack({stack,U,C,D}) ->
>  -    up_stack({stack,U,{},[C|D]}).
>  +up_stack({stack,[],C,D}) ->
>  +    {none,{stack,[C],{},D}}.
>
>   down_stack({stack,U,{},[L|D]}) ->
>      {L,{stack,U,L,D}};
>  +down_stack({stack,U,C,[L|D]}) ->
>  +    {L,{stack,[C|U],L,D}};
>   down_stack({stack,U,{},[]}) ->
>      {none,{stack,U,{},[]}};
>  -down_stack({stack,U,C,D}) ->
>  -    down_stack({stack,[C|U],{},D}).
>  +down_stack({stack,U,C,[]}) ->
>  +    {none,{stack,U,{},[C]}}.
>
>   %% This is get_line without line editing (except for backspace) and
>   %% without echo.
>