segfault due to chpwd_function

[Joel Bernstein <joel@fysh.org>]

I found a scenario leading to a segfault caused by a chpwd_function. The function in question runs to completion when called from command line directly after the 'cd' command, if it is removed from chpwd_functions and called manually. The chpwd_function in question calls the "prompt" function.

Curiously, if I add debug prints to my chpwd_function and precmd_function, I see that the chpwd_function completes and the precmd_function is not entered. Thus I conclude that some state is mutated by my chpwd_function (e.g. use of prompt()?) which causes zsh to segfault after running it.

The segfault (on e.g. cd ~/foo) looks like:
Program received signal EXC_BAD_ACCESS, Could not access memory.
Reason: KERN_INVALID_ADDRESS at address: 0x0000000000007075
0x0000000100020be4 in hasher ()
(gdb) bt
#0  0x0000000100020be4 in hasher ()
#1  0x0000000100020c2b in gethashnode ()
#2  0x0000000100069995 in callhookfunc ()
#3  0x000000010000f057 in bin_cd ()
#4  0x000000010000cf0b in execbuiltin ()
#5  0x0000000100016adb in execcmd ()
#6  0x0000000100017995 in execpline2 ()
#7  0x0000000100017d7c in execpline ()
#8  0x0000000100018e27 in execlist ()
#9  0x0000000100018f65 in execode ()
#10 0x000000010002ab27 in loop ()
#11 0x000000010002bf74 in zsh_main ()
#12 0x0000000100001374 in start ()

And my chpwd_function looks like:
prompt_chpwd () {
        current_prompt=$(prompt -c | tail -n1 | perl -pe 's/\W//g') 
        zgit_isgit && {
                if [ "$current_prompt" != "wunjo" ]
                then
                        prompt wunjo
                fi
        } || {
                if [ "$current_prompt" != "joel" ]
                then
                        prompt joel
                fi
        }
}

I believe I can workaround this issue by setting the desired prompt theme to a var in my chpwd_function and calling prompt() from my precmd_function but it seems an odd behaviour and perhaps a bug?

I am running zsh 4.3.10 (i386-apple-darwin10.0.0). 
Please let me know if I can provide more information.

/joel