Bug #70186 [NEW]: strtotime -1 month has a bug in 2015-07-31

From: vb2005xu at qq dot com Operating system: all PHP version: 5.6.11 Package: Date/time related Bug Type: Bug Bug description:strtotime -1 month has a bug in 2015-07-31 Description: ------------ <?php date_default_timezone_set('Asia/Shanghai'); $tn = strtotime("2015-07-31"); echo date('Y-m' , strtotime("-1 month",$tn)); // why output 2015-07 ? Test script: --------------- <?php date_default_timezone_set('Asia/Shanghai'); $tn = strtotime("2015-07-31"); echo date('Y-m' , strtotime("-1 month",$tn)); Expected result: ---------------- 2015-06 Actual result: -------------- 2015-07 -- Edit bug report at https://bugs.php.net/bug.php?id=70186&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=70186&r=trysnapshot54 Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=70186&r=trysnapshot55 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=70186&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=70186&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=70186&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=70186&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=70186&r=needscript Try newer version: https://bugs.php.net/fix.php?id=70186&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=70186&r=support Expected behavior: https://bugs.php.net/fix.php?id=70186&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=70186&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=70186&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=70186&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=70186&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=70186&r=dst IIS Stability: https://bugs.php.net/fix.php?id=70186&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=70186&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=70186&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=70186&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=70186&r=mysqlcfg