> ------------------------------------------------------------
> revno: 2818.1.6
> revision-id: joro@sun.com-20091021084345-iki6z0uceieoupey
> parent: ramil@mysql.com-20091023112648-gie6o3odj57cxh1e
> committer: Georgi Kodinov <joro@sun.com>
> branch nick: B47780-5.0-bugteam
> timestamp: Wed 2009-10-21 11:43:45 +0300
> message:
>   Bug #47780: crash when comparing GIS items from subquery
>         
>   If the first argument to GeomFromWKB function is a geometry
>   field then the function just returns its value.
>   However in doing so it's not preserving first argument's 
>   null_value flag and this causes unexpected null value to
>   be returned to the calling function.
>         
>   Fixed by updating the null_value of the GeomFromWKB function
>   in such cases (and all other cases that return a NULL e.g.
>   because of not enough memory for the return buffer).