Invalid DateTime::modify with negative offset in PHP 8.2

[pavol-tuka]

Description

DateTime::modify or DateTimeImmutable::modify in PHP 8.2 returns invalid result with negative offset.

$now = new DateTimeImmutable(); // 2023-01-05

$offset = -2;
var_dump($now->modify('+' . $offset . ' days')->format('Y-m-d'));

$offset = 2;
var_dump($now->modify('+' . $offset . ' days')->format('Y-m-d'));

PHP 8.1.14 output:

string(10) "2023-01-03"
string(10) "2023-01-07"

PHP 8.2.1 output:

string(10) "2023-01-07" <-- 2023-01-03 expected
string(10) "2023-01-07"

PHP Version

PHP 8.2.1

Operating System

Linux Mint 21.1

[cmb69]

I can confirm the behavioral change: https://3v4l.org/vMf7Q

We should probably keep BC here, although +-2 is strange, and there are ways to properly handle that in userland.

[derickr]

This was a deliberate change, to work around INT_MAX / INT_MIN issues: https://github.com/derickr/timelib/pull/132/files

[hormus]

#9950 duplicate #10228
DateTimeImmutable::__construct php >= 5.5.0

<?php

$now = new DateTimeImmutable(); //Maybe local timezone 2023-01-05

$days = -2;
if($days) {
$string = str_replace(array('++', '+-'), array('+', '-'), '+' . $days);
var_dump($now->modify(str_replace('-', '+', $string) . ' day')->format('Y-m-d')); // Force plus sign
}

$days = 2;
if($days) {
$string = str_replace(array('++', '+-'), array('+', '-'), '+' . $days);
var_dump($now->modify($string . ' day')->format('Y-m-d'));
}
?>

[cmb69]

Oh, indeed, duplicate of #9950.

[cmb69]

FWIW, the behavior matches the docs now: number | [+-]?[0-9]+.