[Monetdb-developers] [Monetdb-sql-checkins] sql/src/server rel_select.mx, May2009, 1.143.2.4, 1.143.2.5

Stefan Manegold Stefan.Manegold at cwi.nl
Fri Jul 31 08:42:02 CEST 2009


(took me a moment to understand why assigning a NULL is a problem...)

On Fri, Jul 31, 2009 at 08:26:16AM +0200, Stefan de Konink wrote:
> On Fri, 31 Jul 2009, Niels Nes wrote:
> 
> Here you still asign something that could be NULL.

read: "the code still dereferences a pointer that might be NULL"

(apparently, selection can be NULL in this case)

(i.e., "assgining" is not the problem; dereferencing a potential
NULL-pointer it the problem.)

> >  	dnode *n = selection->h;
> >
> > -	(void) where;
> > +	if (!selection)
> > +		return sql_error(sql, 02, "SELECT: the selection or from part is missing");
> 
> So the asignment

(and hence the statement that dereferences pointer selection)

> should be after the check.

> 
> Stefan
> 
> 
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