Bash crashes with segfault on certain script constructs

[Karlheinz Nolte]

  Configuration Information [Automatically generated, do not change]:
  Machine: i686
  OS: linux-gnu
  Compiler: gcc
  Compilation CFLAGS:  -DPROGRAM='bash' -DCONF_HOSTTYPE='i686' 
-DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='i686-pc-linux-gnu' 
-DCONF_VENDOR='pc' -DLOCALEDIR='/usr/share/locale' -DPACKAGE='bash' -DSHELL 
-DHAVE_CONFIG_H  -I.  -I. -I./include -I./lib   -O3 -mtune=athlon-xp 
-mcpu=athlon-xp -mfpmath=sse -funroll-loops -fforce-addr -falign-functions=4 
-mpreferred-stack-boundary=2 -msse -m3dnow -mmmx
  uname output: Linux solfire 2.6.8-rc2-bk10 #1 Sun Aug 1 08:15:00 CEST 2004 
i686 AuthenticAMD unknown GNU/Linux
  Machine Type: i686-pc-linux-gnu
  
  Bash Version: 3.0
  Patch Level: 0
  Release Status: release
  
  Description:
      Bash crashes on Execution of FireHOL 196, which is a shell script.
      No shell script should be able to crash a shell.
  
  Repeat-By:
  
      The following script triggers the segfault.
      This was found by Costa Tsaousis the author of FireHOL.
          He wrotes:

          "I think I have found the bug. The script bellow crashes at the
       third echo (UNSET). It seems to be a problem of the "unset" BASH
       function when erasing arrays. It leaves something behind so that if
       the array just unset is referenced, it produces a segmentation fault.
       According to the documentation the first and the third expansions
       should be exactly the same."
 
      -----------------------------------------------------------
      !/bin/sh
      rule() {
                  echo "1. BEFORE SET:" "${s[@]}"
  
                  local -a s=()
                  echo "2. SET TO EMPTY:" "${s[@]}"
                  unset s
                  echo "3. UNSET:" "${s[@]}"
      }
  
      rule
      -----------------------------------------------------------
  
      Also see Gentoo Bugzilla Bug 58961