Re: Issue with point_ops and NaN

On Tue, Mar 30, 2021 at 11:39:40PM +0800, Julien Rouhaud wrote:
> On Tue, Mar 30, 2021 at 11:02:32AM -0400, Tom Lane wrote:
> > Julien Rouhaud <rjuju123(at)gmail(dot)com> writes:
> > > On Tue, Mar 30, 2021 at 02:47:05PM +0200, Laurenz Albe wrote:
> > >> I'd say that this is certainly wrong:
> > >> SELECT point('NaN','NaN') <@ polygon('(0,0),(1,0),(1,1),(0,0)');
> > >>
> > >> ?column?
> > >> ----------
> > >> t
> > >> (1 row)
> >
> > > Yeah that's what I think too, but I wanted to have confirmation.
> >
> > Agreed --- one could make an argument for either 'false' or NULL
> > result, but surely not 'true'.
>
> I would think that it should return NULL since it's not inside nor outside the
> polygon, but I'm fine with false.
>
> > I wonder if Horiguchi-san's patch [1] improves this case.
>
> Oh I totally missed that patch :(
>
> After a quick look I see this addition in point_inside():
>
> + /* NaN makes the point cannot be inside the polygon */
> + if (unlikely(isnan(x) || isnan(y)))
> + return 0;
>
> So I would assume that it should fix this case too. I'll check tomorrow.

I confirm that this patch fixes the issue, and after looking a bit more at the
thread it's unsurprising since Jesse initially reported the exact same problem.

I'll try to review it as soon as I'll be done with my work duties.