PHP 8.4.*: round seems to ignore the given mode / uses rounding before precision

[Fahl-Design]

Description

The following code:

<?php

var_dump(50*2.55);
var_dump(\round(50 * 2.55,0, PHP_ROUND_HALF_UP));
var_dump(\round(50 * 2.55,0, PHP_ROUND_HALF_DOWN));
var_dump(\round(50 * 2.55,0, PHP_ROUND_HALF_EVEN));
var_dump(\round(50 * 2.55,0, PHP_ROUND_HALF_ODD));

Resulted in this output:

float(127.49999999999999)
float(127)
float(127)
float(127)
float(127)

But I expected this output instead:

float(127.49999999999999)
float(128)
float(127)
float(128)
float(127)

PHP Version

8.4.1-8.4.4

Operating System

https://3v4l.org/Od2ZP

[SakiTakamachi]

@Fahl-Design

To me, the 8.4 behavior looks correct. (This means that the behavior of previous versions is incorrect.)

The four rounding modes you use specify the behavior in edge cases.

127.49999999999999 is not an edge case, so the mode has no effect.

[Fahl-Design]

Indeed your are right .49 is always on the lower half.

I had some failing tests in my lib after adding 8.4 and now fixed it for both versions with 50*2.550001

Thanks anyway