Bug in history changes

[Peter Stephenson <pws@xxxxxxx>]

The latest version of the history code is causing zcalc to crash.  zcalc
now tries to use its own separate history file; it's a bit hacky because
the history interface isn't intended for use like this.  The instruction
that triggers it is setting HISTSIZE to 0.

(gdb) bt
#0  0x3b200 in putoldhistentryontop (keep_going=-3664) at ../../Src/hist.c:937
#1  0x3ce44 in resizehistents () at ../../Src/hist.c:1776
#2  0x5d9c4 in histsizesetfn (pm=0x9b330, v=4294967296)
    at ../../Src/params.c:2915
#3  0x5a728 in setstrvalue (v=0xffbee7f0, val=0xef3a8 "0")
    at ../../Src/params.c:1637
#4  0x5b740 in assignsparam (s=0xbbfe0 "", val=0xef3a8 "0", augment=0)
    at ../../Src/params.c:1991
#5  0x1ef64 in typeset_single (cname=0xbbfd0 "local", 
    pname=0xbbfd8 "HISTSIZE", pm=0x9b330, func=0, on=131072, off=0, roff=0, 
    value=0xbbfe1 "0", altpm=0x0) at ../../Src/builtin.c:1868
#6  0x203f0 in bin_typeset (name=0xbbfd0 "local", argv=0xffbee9bc, 
    ops=0xffbee9d0 "", func=0) at ../../Src/builtin.c:2127
#7  0x1aa04 in execbuiltin (args=0xbbfb0, bn=0x99c50)
    at ../../Src/builtin.c:377
#8  0x2df58 in execcmd (state=0xffbeed80, input=0, output=0, how=2, last1=2)
    at ../../Src/exec.c:2306
#9  0x2b2b4 in execpline2 (state=0xffbeed80, pcode=192, how=2, input=0, 
    output=0, last1=0) at ../../Src/exec.c:1201
#10 0x2a808 in execpline (state=0xffbeed80, slcode=128, how=2, last1=0)
    at ../../Src/exec.c:991
#11 0x2a2a8 in execlist (state=0xffbeed80, dont_change_job=1, exiting=0)
    at ../../Src/exec.c:826
#12 0x29fb0 in execode (p=0xf37c8, dont_change_job=1, exiting=0)
    at ../../Src/exec.c:729
#13 0x2ffac in execautofn (state=0xd5de8, do_exec=0) at ../../Src/exec.c:3245
#14 0x2dd0c in execcmd (state=0xffbef130, input=0, output=0, how=18, last1=2)
    at ../../Src/exec.c:2253
#15 0x2b2b4 in execpline2 (state=0xffbef130, pcode=0, how=18, input=0, 
    output=0, last1=0) at ../../Src/exec.c:1201
#16 0x2a808 in execpline (state=0xffbef130, slcode=96, how=18, last1=0)
    at ../../Src/exec.c:991
#17 0x2a2a8 in execlist (state=0xffbef130, dont_change_job=1, exiting=0)
    at ../../Src/exec.c:826
#18 0x29fb0 in execode (p=0xf32e8, dont_change_job=1, exiting=0)
    at ../../Src/exec.c:729
#19 0x30630 in runshfunc (prog=0xf32e8, wrap=0x0, name=0xbbdf8 "zcalc")
    at ../../Src/exec.c:3492
#20 0x303f4 in doshfunc (name=0xca520 "zcalc", prog=0xf32e8, doshargs=0xef3d0, 
    flags=0, noreturnval=0) at ../../Src/exec.c:3407
#21 0x2ff38 in execshfunc (shf=0xd5de8, args=0xbbdd0) at ../../Src/exec.c:3217
#22 0x2decc in execcmd (state=0xffbef670, input=0, output=0, how=18, last1=2)
    at ../../Src/exec.c:2295
#23 0x2b2b4 in execpline2 (state=0xffbef670, pcode=4, how=18, input=0, 
    output=0, last1=0) at ../../Src/exec.c:1201
#24 0x2a808 in execpline (state=0xffbef670, slcode=96, how=18, last1=0)
    at ../../Src/exec.c:991
#25 0x2a2a8 in execlist (state=0xffbef670, dont_change_job=0, exiting=0)
    at ../../Src/exec.c:826
#26 0x29fb0 in execode (p=0xbbd88, dont_change_job=0, exiting=0)
    at ../../Src/exec.c:729
#27 0x3e3a8 in loop (toplevel=1, justonce=0) at ../../Src/init.c:165
#28 0x40ad0 in zsh_main (argc=1, argv=0x1) at ../../Src/init.c:1214
#29 0x1a220 in main (argc=1, argv=0xffbef844) at ../../Src/main.c:37

    if (he != hist_ring->down) {
=>	he->up->down = he->down;
	he->down->up = he->up;
	he->up = hist_ring;
	he->down = hist_ring->down;
	hist_ring->down = he->down->up = he;
    }

(gdb) p he->up
$1 = 0xffffffff

-- 
Peter Stephenson <pws@xxxxxxx>                  Software Engineer
CSR Ltd., Science Park, Milton Road,
Cambridge, CB4 0WH, UK                          Tel: +44 (0)1223 392070


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