Doc #79453 [Opn->Nab]: Modify -1 month works incorrectly at the end of some months

Edit report at https://bugs.php.net/bug.php?id=79453&edit=1 ID: 79453 Updated by: derick@php.net Reported by: moras dot pawel at gmail dot com Summary: Modify -1 month works incorrectly at the end of some months -Status: Open +Status: Not a bug Type: Documentation Problem Package: Date/time related Operating System: Ubuntu 19.04 PHP Version: 7.2.29 Block user comment: N Private report: N New Comment: Thank you for taking the time to write to us, but this is not a bug. Please double-check the documentation available at http://www.php.net/manual/ and the instructions on how to report a bug at http://bugs.php.net/how-to-report.php This is already documented at https://www.php.net/manual/en/datetime.examples-arithmetic.php Previous Comments: ------------------------------------------------------------------------ [2020-04-07 06:03:19] moras dot pawel at gmail dot com Description: ------------ modify result is not intuitive when going back one month. If the current month has more days than the last one, modify ('-1 month') can end up in the same month. I believe, if that is the case, it should fall back to the last day of last month. The current way this works is completely unintuitive, and at least should be mentioned in the docs. Test script: --------------- $date = new DateTime (); $date->setDate (2020, 03, 30); // 31 days in march echo $date->format ("Y-m-d h:m:s") . PHP_EOL; $date->modify ("-1 month"); // only 28 days in february echo $date->format ("Y-m-d h:m:s") . PHP_EOL; Expected result: ---------------- 2020-03-30 07:03:18 2020-02-28 07:03:18 Actual result: -------------- 2020-03-30 07:03:18 2020-03-01 07:03:18 ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=79453&edit=1