Bug #77220 [Opn->Nab]: Problem for month March (DateTime::sub)

Edit report at https://bugs.php.net/bug.php?id=77220&edit=1 ID: 77220 Updated by: cmb@php.net Reported by: info at 4md dot eu Summary: Problem for month March (DateTime::sub) -Status: Open +Status: Not a bug Type: Bug Package: Date/time related Operating System: Any PHP Version: Irrelevant -Assigned To: +Assigned To: cmb Block user comment: N Private report: N New Comment: . Previous Comments: ------------------------------------------------------------------------ [2018-11-29 16:35:15] cmb@php.net 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 See <http://php.net/manual/en/datetime.sub.php#refsect1-datetime.sub-examples>, example 3. ------------------------------------------------------------------------ [2018-11-29 15:11:03] info at 4md dot eu Description: ------------ If substract 1 Month for 31/30/29 march => Not correctly subtract (possible problem to February Month). Test script: --------------- <?php $intervalMonth = new DateInterval('P1M'); $dates = ['2019-01-30', '2019-02-28', '2019-03-29', '2019-03-30', '2019-03-31', '2019-04-30']; foreach($dates as $date){ $d = new DateTime($date); // Substract 1 Month $d->sub($intervalMonth); $subMonth = $d->format('Y-m-d'); // Adding 1 Month $d->add($intervalMonth); $addMonth = $d->format('Y-m-d'); // Echo information if(substr($date, 0, 7) === '2019-03'){ echo '*'; } echo 'Now: '.$date.'; Sub 1Month: '.$subMonth."; Add Month: ".$addMonth."\n"; } echo "\n"; echo '* BUG'; Actual result: -------------- Now: 2019-01-30; Sub 1Month: 2018-12-30; Add Month: 2019-01-30 Now: 2019-02-28; Sub 1Month: 2019-01-28; Add Month: 2019-02-28 *Now: 2019-03-29; Sub 1Month: 2019-03-01; Add Month: 2019-04-01 *Now: 2019-03-30; Sub 1Month: 2019-03-02; Add Month: 2019-04-02 *Now: 2019-03-31; Sub 1Month: 2019-03-03; Add Month: 2019-04-03 Now: 2019-04-30; Sub 1Month: 2019-03-30; Add Month: 2019-04-30 * BUG ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=77220&edit=1