Re: [PATCH] evaluate: print error for null string befort assert statement

[Pablo Neira Ayuso <pablo@netfilter.org>]

On Thu, Nov 23, 2017 at 10:25:51PM +0100, Florian Westphal wrote:
> Harsha Sharma <harshasharmaiitr@gmail.com> wrote:
> > Print error "Null string is not allowed" before assert statement.
> > For e.g.
> > nft add rule filter input meta iifname '""'
> > Error: Null String is not allowed
> > add rule filter input meta iifname ""
> 
> Is there any case where "" should be allowed?
> 
> If not, I'd rather change scanner.l to not recognize "" as
> a quoted string.

We'll get error reporting like this if we handle this from the
scanner:

# nft add rule x y ct label \"\"
Error: syntax error, unexpected junk
add rule x y ct label ""
                      ^

This is just two extra lines in the validation step and it is not
worth to optimize an error case, ie. do it earlier. So I'm feeling
inclined to take this one.

I will mangle the error message to "Empty string is not allowed".
"Null" probably sounds too programmer thing.

Thanks!