[PHP82] DateTime modify does not work with addition of minus values

[shyim]

Description

The following code:

<?php
$a = (new \DateTimeImmutable('2022-05-01 22:00:00'))->modify('+-30 seconds');

var_dump($a);

Resulted in this output:

Adds 30 seconds

But I expected this output instead:

Should substract 30 seconds like before

https://3v4l.org/6eMQj

It did work before RC3. I am not sure if this is intended or not 😅

PHP Version

PHP 8.2.0 RC6

Operating System

macOs Ventura 13.1 Beta 2

[derickr]

You are right that this is a change, but it is expected and on purpose to fix another bug: derickr/timelib@44cfe97 / derickr/timelib#124

It now picks the first sign that it finds... although perhaps it should warn on the second sign. In any case, the workaround is to change the +- to just - in your code.

[derickr]

FWIW, the original behaviour was pretty much a bug, so I don't think we need to do anything here, and hence I'm closing this issue.

[aquavark]

@derickr I know you closed this, but I just wanted to add that this change also affected strtotime, which broke applications under test in 8.2 in a non-obvious manner (caused duplication of dates in a dynamic built array that then caused data overwriting) and I couldn't find it listed as a PHP 8.2 breaking change anywhere. I've requested to see if PHPStan or PHPCompatibility (for codesniffer) can help detect this as a breaking change. As it was accepted methodology previously (albeit not to the written standard, I accept that) it may cause other breakages that are non-obvious.

[cmb69]

Documented as php/doc-en@cf220d0.

[aquavark]

The other variation, -+, is also no longer possible in 8.2 but worked (in the mathematical sense) in PHP versions from somewhere in PHP5 up to PHP8.1 as well (not that it's likely to happen in most code, but was possible if you were [un]suitably minded).

[cmb69]

@aquavark, done with php/doc-en@ef51b1c.

[aquavark]

Appreciate the update. Thanks.