[erlang-bugs] Silly eshell history behavior

[Matthew Dempsky]

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.