Bug #75477 [NEW]: last weekday of this month returns previous month when date is set

From: wouter at deinternetjongens dot nl Operating system: Linux, mac os PHP version: 7.1.11 Package: Date/time related Bug Type: Bug Bug description:last weekday of this month returns previous month when date is set Description: ------------ We came across a bug when trying to get the last weekday of a month. When we first setted a new date and afterwards modified it to get the last weekday of that month it returns the last weekday of the month before the month given. Test script: --------------- $datetime = new DateTime()->setDate(2017, 12, 1); var_dump($datetime->modify('last weekday this month'); Expected result: ---------------- DateTime {#12086 +"date": "2017-12-30 00:00:00.000000", +"timezone_type": 3, +"timezone": "UTC", } Actual result: -------------- DateTime {#12086 +"date": "2017-11-30 00:00:00.000000", +"timezone_type": 3, +"timezone": "UTC", } -- Edit bug report at https://bugs.php.net/bug.php?id=75477&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=75477&r=trysnapshot54 Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=75477&r=trysnapshot55 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=75477&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=75477&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=75477&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=75477&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=75477&r=needscript Try newer version: https://bugs.php.net/fix.php?id=75477&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=75477&r=support Expected behavior: https://bugs.php.net/fix.php?id=75477&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=75477&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=75477&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=75477&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=75477&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=75477&r=dst IIS Stability: https://bugs.php.net/fix.php?id=75477&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=75477&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=75477&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=75477&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=75477&r=mysqlcfg