Bug #75012 [NEW]: strtotime('-x month') has an unexpected behavior

From: paladinotoldo at gmail dot com Operating system: any PHP version: 7.0.21 Package: *General Issues Bug Type: Bug Bug description: strtotime('-x month') has an unexpected behavior Description: ------------ --- From manual page: http://www.php.net/function.strtotime --- strtotime('-1 month') has an unexpected behavior in 31th day of month Test script: --------------- $t =strtotime('31-07-2017'); echo "\n". date('d/m/Y',$t ); $timestamp = strtotime('-1 month',$t ); echo "\n".date("d/m/Y", $timestamp); $timestamp = strtotime('-2 month',$t ); echo "\n". date("d/m/Y", $timestamp); $timestamp = strtotime('-3 month',$t ); echo "\n". date("d/m/Y", $timestamp); $timestamp = strtotime('-4 month',$t ); echo "\n". date("d/m/Y", $timestamp); $timestamp = strtotime('-5 month',$t ); echo "\n". date("d/m/Y", $timestamp); Expected result: ---------------- 31/07/2017 30/06/2017 31/05/2017 30/04/2017 31/03/2017 28/02/2017 or 31/07/2017 01/07/2017 01/06/2017 02/05/2017 02/04/2017 03/03/2017 Actual result: -------------- 31/07/2017 01/07/2017 31/05/2017 01/05/2017 31/03/2017 03/03/2017 -- Edit bug report at https://bugs.php.net/bug.php?id=75012&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=75012&r=trysnapshot54 Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=75012&r=trysnapshot55 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=75012&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=75012&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=75012&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=75012&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=75012&r=needscript Try newer version: https://bugs.php.net/fix.php?id=75012&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=75012&r=support Expected behavior: https://bugs.php.net/fix.php?id=75012&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=75012&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=75012&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=75012&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=75012&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=75012&r=dst IIS Stability: https://bugs.php.net/fix.php?id=75012&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=75012&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=75012&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=75012&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=75012&r=mysqlcfg