Re: [PATCH] udev-009: Allow build with empty EXTRAS

[Adam Kropelin <akropel1@rochester.rr.com>]

On Wed, Dec 17, 2003 at 12:31:00AM -0800, Greg KH wrote:
> On Tue, Dec 16, 2003 at 10:04:06PM -0500, Adam Kropelin wrote:
> > Need to let the shell expand $EXTRAS so it can properly detect an empty
> > list. Without this patch, the build fails whenever $EXTRAS is empty.
> 
> $ export EXTRAS> $ make
> $ set | grep EXTRA
> EXTRAS> $ 
> 
> I can't duplicate this problem at all.  Someone else once reported it on
> the linux-hotplug-devel list, with much the same fix up patch, but later
> said they couldn't reproduce it either.
> 
> What version of make are you using?

It's actually the version of bash that's important. Prior to 2.05a, bash
was unable to handle for loops with empty words lists. From the
bash-2.05a changelog:

	p.  `for' loops now allow empty word lists after `in', like the 
	    latest POSIX drafts require.

So bash-2.05 dies on...

	for test in ; do echo $test ; done

...while bash-2.05a accepts it just fine.

Both versions can handle this case if the shell itself does the
expansion that results in the empty list. So that's where my workaround
came from.

--Adam



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