Re: Breaking change of rounding behavior in PHP 8.4

On Fri, Jul 12, 2024, at 13:24, Christoph M. Becker wrote: > Hi all, > > there has been a "small" change in the rounding logic of > _php_math_round()[1] a couple of months ago. A respective ticket, > claiming the new behavior would be a bug[2] had been filed a while ago > without proper triage so far. I'm bringing this to your attention, > because I'm afraid that there will be (many) more bug reports about this > in the future (note that the change only affects master, and only PHP > 8.4.0alpha1 has been released yet, so it is probably not widespreadly > tested yet). At the very least we should be sure that we want to keep > this change, and document it well, to avoid discussions in every filed > ticket. > > My personal stance on this is simple: floating point arithmetic is not > exact per se, and changes to how PHP handles the details should only be > introduced, if they clearly improve things. This change apparently > improves some cases, but worsens others. Thus, I think the change > should better be reverted, and if at all, postponed to PHP 9, since I > neither regard this change as bug fix nor as a feature. > > What do you think? > > [1] <https://github.com/php/php-src/pull/12222> > [2] <https://github.com/php/php-src/issues/14332> > > Cheers, > Christoph > I guess the real question is: how many of these numbers should be the same? https://3v4l.org/tgRMc/rfc#vgit.master — Rob