Re: [patch] Fix crash on NULL rl_prompt

[Pedro Alves <pedro at codesourcery dot com>]

On Tuesday 30 March 2010 18:04:57, Jan Kratochvil wrote:
> On Tue, 30 Mar 2010 18:41:20 +0200, Pedro Alves wrote:
> > But, how did rl_prompt end up NULL in the first place?
> 
> I do not know.  I have spent some time trying to reproduce it reading the
> source but gave up after some reasonable time.  Bugreport comes from an
> automated crash reporter (ABRT) where the person only sometimes can/gives more
> info.  Asked now for a reproducer.

My guess is, either readline wasn't setup proper at all, or,
the prompts stack got busted (get_prompt/set_prompt/PROMPT), which
I've seen happen before with target-async mode.

> An existing bug a user cannot notice is ... no longer a bug, isn't it?

Err, whatever.

(Nowhere in this thread have I seen mentioned that GDB (or its
prompt) doesn't get busted further down the road, mind you.)

On Tuesday 30 March 2010 18:13:20, Tom Tromey wrote:
> Jan> I do not know.
> 
> Yeah, it is not great that we don't know how to reproduce it.
> 
> But, given that part of the readline contract is that rl_prompt==NULL is
> a valid state, I think tui_prep_terminal ought to cope with that as
> well>.  Maybe there is also some other bug somewhere else, but that
> doesn't affect the correctness of this particular patch.

But isn't `rl_prompt' always built from input feed to readline?
GDB always gives readline a non-NULL prompt, from what I've seen.
Hence, I wouldn't be so fast in calling it correct, but I'm
not going to spend more time on this.  My intention was mainly
to comment on the xstrdup/xmalloc remark.

-- 
Pedro Alves