2 regressions related to PROMPT_COMMAND

[smallnow]

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='/a/local/share/locale' -DPACKAGE='bash' 
-DSHELL -DHAVE_CONFIG_H   -I.  -I. -I./include -I./lib   -g -O2
uname output: Linux ul 2.6.27-12-generic #1 SMP Thu Feb 5 09:26:42 UTC 2009 
x86_64 GNU/Linux
Machine Type: x86_64-unknown-linux-gnu

Bash Version: 4.0
Patch Level: 0
Release Status: release

Description:
Neither of these happen on the same system with 3.2.39(1)-release.

Bug #1:
do:
PROMPT_COMMAND='$(cd)'
Then do anything that would change your prompt, for example change directories 
when PS1 contains the current directory. You will see the prompt will never 
update when PROMPT_COMMAND contains any command substitution. It just remains 
whatever it was when this was set. I used $(cd) as a trivial command 
substitution, but any command substitution seems to have the same effect.

I actually had some useful code including parameter expansions going on in my 
PROMPT_COMMAND. This took quite a while to figure out.


Bug #2:
do:
PS1=
PROMPT_COMMAND='echo -ne $PWD'
press up, then down.
This brings up the last history and then goes to the new command again. The 
cursor goes goes to the beginning of the line screwing up text from 
PROMPT_COMMAND. This also happens with vi-mode commands. I put PS1= so that it 
doesn't confuse the issue, but that is not necessary.


Btw, thanks for bash 4. :)

- Ian Kelling