inconsistent exit status of ((count++))

[Andrew Benton]

Configuration Information [Automatically generated, do not change]:
Machine: x86_64
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS:  -DPROGRAM='bash' -DCONF_HOSTTYPE='x86_64' 
-DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='x86_64-unknown-linux-gnu' 
-DCONF_VENDOR='unknown' -DLOCALEDIR='/usr/share/locale' -DPACKAGE='bash' 
-DSHELL -DHAVE_CONFIG_H   -I.  -I. -I./include -I./lib   -g -O2
uname output: Linux eccles 2.6.35-rc6 #1 SMP Fri Jul 23 11:52:29 BST 
2010 x86_64 x86_64 x86_64 GNU/Linux
Machine Type: x86_64-unknown-linux-gnu

Bash Version: 4.1
Patch Level: 2
Release Status: release

Description:
        [Detailed description of the problem, suggestion, or complaint.]

If I use set -e to make my scripts exit on error, the scripts fail if I 
use something like:

count=0
((count++))

Repeat-By:

andy:~$ count=0
andy:~$ ((count++))
andy:~$ echo $?
1
andy:~$ ((count++))
andy:~$ echo $?
0

Fix:

This isn't a fix but I can work around this bug if I use ((++count))

andy:~$ count=0
andy:~$ ((++count))
andy:~$ echo $?
0
andy:~$