Re: [HACKERS] Another nasty cache problem

Patrick Welche <prlw1@newn.cam.ac.uk> writes: 
> +       if (!string)
> +               elog(ERROR, "Trying to convert NULL text to integer (int2)");

This is unreasonable behavior.  The correct patch is just
if (!string)    return 0;

which will allow the function manager to plow ahead with returning the
NULL that it's going to return anyway.  See the past pghackers threads
about redesigning the function manager interface if you don't understand
what's going on here.
        regards, tom lane