[Groff] Re: Possible zsh contention in pdfroff (Re: [autoconf] ensure a VPATH build)

[Noah Misch]

On Tue, Feb 21, 2006 at 01:49:12PM +0000, Keith MARSHALL wrote:
> Ralf Wildenhues wrote:
> > Some zsh versions have NULLCMD set to `cat' by default, so the
> > command [`>> $REFFILE'] will be equivalent to
> >
> >    cat >> $REFFILE
> >
> > and thus will read from stdin until EOF.  If stdin is connected to
> > the terminal, the innocent user will think the program hangs; if it
> > points to an open file, that file will end up in $REFFILE.
> 
> Given the complete absence of related of bug reports, either:
> 
> 1) This isn't true (which seems unlikely), or (more likely)
> 
> 2) No one has attempted to build groff >= 1.19.2, or to use pdfroff,
>    on any system where /bin/sh is linked to zsh.
> 
> Can anyone either confirm or refute the hypothesis that there may be
> a zsh related contention in pdfroff?

I built groff 1.19.2 on powerpc-apple-darwin5.5, and it worked fine.  This zsh
sets NULLCMD=: when invoked as sh:

$ ls -l /bin/{sh,zsh}
-r-xr-xr-x    1 root     wheel      449616 Aug 30  2002 /bin/sh
-rwxr-xr-x    1 root     wheel      449616 Aug 30  2002 /bin/zsh
$ /bin/sh  -c 'echo $NULLCMD'
:
$ /bin/zsh -c 'echo $NULLCMD'
cat
$ /bin/zsh -c 'echo $ZSH_VERSION'
3.0.8