Re: zsh4.0.1-pre4 : backticks fail if SHLVL nonexistant

[Peter Stephenson <pws@csr.com>]

> I've downloaded and built zsh4.0.1-pre4.  I was finding that any attempt
> to use backtick-substitution was resulting in a core dump.  I rebuilt
> with -g and tracked it down to a null pointer 'pm' in setiparam, for an
> attempt to set SHLVL from line 2316 of exec.c.  Unfortunately, I had
> SHLVL being unset by a line in my .zshenv.  (In order to reduce the
> environment to a clean initial state before adding new defintions, I
> unset everything except for a defined list of variables at the start of
> .zshenv.  Previously, SHLVL wasn't one ofthem.  It worked OK with zsh
> v3.1.5).

I can reproduce such a crash reliably with:

% unset SHLVL
% (( SHLVL-- ))
BUG: parameter not created
zsh: segmentation fault (core dumped)  ./zsh

This probably doesn't involve the line in exec.c, but it's almost certainly
the same root, so it'll give something to work on.  (The BUG message only
appears if configured with --enable-zsh-debug.)

-- 
Peter Stephenson <pws@csr.com>                  Software Engineer
CSR Ltd., Unit 300, Science Park, Milton Road,
Cambridge, CB4 0XL, UK                          Tel: +44 (0)1223 392070


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