Re: get_fn_expr_variadic considered harmful

Andres Freund <andres(at)2ndquadrant(dot)com> writes:
> On 2014-04-01 12:52:54 -0400, Tom Lane wrote:
>> We could possibly salvage something by redefining funcvariadic as only
>> being true if VARIADIC was used *and* the function is VARIADIC ANY,
>> so that it returns to not being different for semantically-equivalent
>> cases. This would be a bit messy, since it would not un-break the
>> behavior for any already stored rules or indexes in 9.3 databases.
>> But I'm not sure there is any good way to make the problem magically
>> go away in 9.3 databases.

> It's pretty damn ugly, but if we're going for magic in around those
> edges, we could just force the new behaviour in readfuncs.c. IIUC all
> the neccessary data for it is there.

I don't want either readfuncs or equalfuncs going in for catalog lookups,
which is what they'd have to do to fix it at that level (the key point
being they'd have to find out whether the called function is declared as
VARIADIC ANY). Too much risk of unpleasant side effects if we do that.
The parser, on the other hand, has ready access to the function's
parameter list when building a FuncExpr.

regards, tom lane