Greetings,
* Robert Haas (robertmhaas@gmail.com) wrote:
> On Wed, Nov 28, 2018 at 9:17 PM Stephen Frost <sfrost@snowman.net> wrote:
> > > Actually, some geometric comparisons are performed counting
> > > tolerance margin, the validity of which is in doubt. Their
> > > behavior has been changed in recent major version and still has a
> > > room for improvement, and the functions are parallel-safe and
> > > immutable. Immutablity is mentiond mainly in the light of
> > > optimization in the documentation.
> >
> > I really don't buy off on these arguments in the least. I also didn't
> > say that a function wasn't allowed to change- but that the output of an
> > immutable function, for a given input, shouldn't change and in the very
> > rare case where we absolutely had to make a change, it had better be for
> > a very good reason and we need to consider the impact on user indexes.
>
> I think you're getting a little carried away here. Kyotaro-san's
> argument seems extremely strong to me, so much so that I can't really
> see how you can argue against it. If we have a bug that says 1 + 1 =
> 3, we are going to fix it. We're not going say, oh, well, it's an
> immutable function, so we're just going to carry on having it return
> the wrong answer. That would be ridiculous.
>
> It feels to me like you are trying to turn this into some kind of
> principled stand against evil people who don't care about
> immutability, but rumors that the barbarians are at the gates seem
> greatly exaggerated from where I sit.
I'd suggest you read through the rest of the thread and see my response
to Tom.
Thanks!
Stephen