Re: zsh-3.1.9-dev-6 crashes occassionally

["Thomas Köhler" <jean-luc@picard.franken.de>]

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On Mon, Oct 30, 2000 at 09:32:00AM +0100,
Sven Wischnowsky <wischnow@informatik.hu-berlin.de> wrote:
> Thomas Koehler wrote:
> 
> > Hi there,
> > I have the following problem with zsh-3.1.9-dev-6 on Debian GNU/Linux
> > for i386:
> > Sometimes, while trying to complete, zsh crashes and dumps core. In
> > fact, the problem has been there for quite a while now, perhaps it has
> > been there since the new completions system has been introduced - I
> > don't know. The problem is: I can't reproduce the bug. It just happens
> > to occur every once in a while.
> > Well, this is not the only problem: Sometimes, zsh forgets its
> > completion settings. I use this line in my .zshrc:
> > zstyle ':completion:*' completer _complete _ignored _match _correct _approx=
> > imate _prefix
> > Now, sometimes, for some strange reason, zsh forgets to complete on tab
> > and starts to _correct things right away: For example, I had a directory
> > "abcdef" and a directory "abx" and typed "cd abc<TAB>" which resulted in
> > "cd abx".
> 
> Thomas sent me his .zshrc, I tried, but couldn't reproduce it. But I
> think I know where it comes from and why I never could reproduce it
> (he reported it already quite some time ago, I think; or something
> similar?).

Yes, I reported this a while ago.

> Thomas uses a trap handler for the ALRM signal and with TMOUT=1 to
> update his prompt. The trap handler uses several local parameters.
> Since zsh invokes (shell-code) trap handler asynchronously from the
> signal handler, this could easily mess up the parameter table if the
> signal comes at a time when the completion code is playing with the
> parameter table itself.

Ugh.
Would it help if I'd change my signal handler not to use local
parameters?

> We talked about this several times already. We either need to protect
> parts of the code (blocking signals there) or we should make the
> signal handlers do as little as possible, setting only some flags or
> something like that and call the trap handler shell-code somewhere
> else where it can be called savely. We `decided' to use the second
> solution, I think (and the first one is expensive and we have to find
> all the right places and...).
> 
> We could also use a mixture: a global flag that tells the signal code
> that it's save to invoke the trap handler right away but normally it
> would only make them be called later. That flag could be set when zsh
> is waiting for an external command, reading somethin or whatever.
> (This could be a good reason to finally write a function that is
> called everywhere zsh waits for something. And then we could allow
> modules to hook into it or something.)

Sounds like a nice idea.

> Bye
>  Sven

CU,
Thomas

-- 
 Thomas Köhler Email:   jean-luc@picard.franken.de     | LCARS - Linux
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