Bug #65730 [NEW]: DateTime::format('W') returns wrong week number

From: glavic at gmail dot com Operating system: ALL PHP version: Irrelevant Package: Date/time related Bug Type: Bug Bug description:DateTime::format('W') returns wrong week number Description: ------------ DateTime::format('W') returns wrong week number when date is 2013-12-30 or 2013-12-31. Test script: --------------- <?php $dt = new DateTime; for ($w = 52; $w <= 54; $w++) { $dt->setISODate(2013, $w); print_r($dt); echo $dt->format('Y W') . "\n\n"; } # see this script running on all php versions http://3v4l.org/9aua5 Expected result: ---------------- DateTime Object ( [date] => 2013-12-23 11:02:12 [timezone_type] => 3 [timezone] => UTC ) 2013 52 DateTime Object ( [date] => 2013-12-30 11:02:12 [timezone_type] => 3 [timezone] => UTC ) 2014 01 # or 2013 53, but surely not 2013 01 !!! DateTime Object ( [date] => 2014-01-06 11:02:12 [timezone_type] => 3 [timezone] => UTC ) 2014 02 Actual result: -------------- DateTime Object ( [date] => 2013-12-23 11:02:12 [timezone_type] => 3 [timezone] => UTC ) 2013 52 DateTime Object ( [date] => 2013-12-30 11:02:12 [timezone_type] => 3 [timezone] => UTC ) 2013 01 DateTime Object ( [date] => 2014-01-06 11:02:12 [timezone_type] => 3 [timezone] => UTC ) 2014 02 -- Edit bug report at https://bugs.php.net/bug.php?id=65730&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=65730&r=trysnapshot54 Try a snapshot (PHP 5.3): https://bugs.php.net/fix.php?id=65730&r=trysnapshot53 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=65730&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=65730&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=65730&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=65730&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=65730&r=needscript Try newer version: https://bugs.php.net/fix.php?id=65730&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=65730&r=support Expected behavior: https://bugs.php.net/fix.php?id=65730&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=65730&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=65730&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=65730&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=65730&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=65730&r=dst IIS Stability: https://bugs.php.net/fix.php?id=65730&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=65730&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=65730&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=65730&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=65730&r=mysqlcfg