Re: Emacs 27.1 released

[Eli Zaretskii]

> From: Mattias Engdegård <mattiase@acm.org>
> Date: Wed, 12 Aug 2020 21:07:05 +0200
> Cc: emacs-devel@gnu.org
> 
> > How easily would people bump into this in real-life use cases?  I
> > think the answer to that will tell how important is it to fix it in
> > Emacs 27.
> 
> We have no idea. Most bugs are never reported; people blame themselves and 
> try a different approach, or just blame Emacs in general. That's why it's 
> important to fix bugs we find even absent any concrete evidence that it has 
> affected anyone else.

That kind of abstract arguments don't help.  So I'm left to my own
devices, and therefore please leave this change on master.

> >>> I'm uneasy with this, as it would indirectly affect many functions.
> >> 
> >> Which many functions did you have in mind?
> > 
> > Its callers inside Calc.  Suppose there's some subtle issue with the
> > change, or some unintended consequence.
> 
> Mind being more specific?

I just counted its callers, that's all.  A change in a function that
has many callers could have unintended consequences beyond the
function itself.

> >  OTOH, how probable is it to have a negative x here?
> 
> The post-hoc probability is 1 because a user was affected by and reported the 
> bug, but that's not the point: the erroneous simplification GCD(x, 0) -> x 
> leads to trouble later on, as the report shows.

I thought you were going to help me make a better decision, but I
guess I was too naïve.  Please leave this one on master as well.