Bug #79916 [NEW]: Inconsistency when modifying date

From: david dot kmenta at me dot com Operating system: PHP version: Irrelevant Package: Date/time related Bug Type: Bug Bug description:Inconsistency when modifying date Description: ------------ When I'm adding (for example) months to the datetime, it shouldn't matter if I add months one-by-one by calling the "modify" method multiple times, or at once with one call. I know it's caused by the February and I don't care if "1 month" means 30, 31, ... days, but I think that there should be a consistent result regardless the way the "modify" method is used. Test script: --------------- $today = new \DateTimeImmutable('2020-01-30 11:00:00'); var_dump($today->modify('+2 months')->format('Y-m-d H:i:s')); var_dump($today->modify('+1 month')->modify('+1 month')->format('Y-m-d H:i:s')); Expected result: ---------------- string(19) "2020-03-30 11:00:00" string(19) "2020-03-30 11:00:00" or string(19) "2020-04-01 11:00:00" string(19) "2020-04-01 11:00:00" Actual result: -------------- string(19) "2020-03-30 11:00:00" string(19) "2020-04-01 11:00:00" -- Edit bug report at https://bugs.php.net/bug.php?id=79916&edit=1 -- Fix committed: https://bugs.php.net/fix.php?id=79916&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=79916&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=79916&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=79916&r=needscript Try newer version: https://bugs.php.net/fix.php?id=79916&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=79916&r=support Expected behavior: https://bugs.php.net/fix.php?id=79916&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=79916&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=79916&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=79916&r=globals PHP version support discontinued: https://bugs.php.net/fix.php?id=79916&r=phptooold Daylight Savings: https://bugs.php.net/fix.php?id=79916&r=dst IIS Stability: https://bugs.php.net/fix.php?id=79916&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=79916&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=79916&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=79916&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=79916&r=mysqlcfg