#49081 [NEW]: DateTime::diff calculates diffs incorrectly

From: nate at frickenate dot com Operating system: PHP version: 5.3.0 PHP Bug Type: Date/time related Bug description: DateTime::diff calculates diffs incorrectly Description: ------------ DateTime::diff calculates diffs incorrectly. As an example, the diff of 2009-01-01 and 2009-03-31 *should be* "2 months, 30 days". 2009-01-01 + 2 months = 2009-03-01, + 30 days = 2009-03-31. Taking 2009-01-01 and using DateTime::add() to add 'P2M30D' does indeed result in 2009-03-31. This is correct. However, running the diff() of 2009-01-01 and 2009-03-31 returns "3 months, 2 days". add()ing 2009-01-01 + 'P3M2D' returns 2009-04-03 instead of 2009-03-31 (as it should, since the diff that told us to add 3M2D was incorrect). Reproduce code: --------------- <? $jan_1 = new DateTime('2009-01-01'); $mar_31 = new DateTime('2009-03-31'); var_dump(date_diff($jan_1, $mar_31)); var_dump($jan_1->add(new DateInterval('P2M30D'))); // correct period var_dump($jan_1->add(new DateInterval('P3M2D'))); // incorrect period // END EXAMPLE CODE - following is just extra fluff // here's the replacement function I am currently // using to calculate the correct diff until the // built-in method is patched and functional function date_diff2 ($t1, $t2) { if (! preg_match('/^\d+\z/', $t1) && ($t1 = strtotime($t1)) === false) return false; if (! preg_match('/^\d+\z/', $t2) && ($t2 = strtotime($t2)) === false) return false; if ($t1 > $t2) list($t1, $t2) = array($t2, $t1); $diffs = array( 'years' => 0, 'months' => 0, 'days' => 0, 'hours' => 0, 'minutes' => 0, 'seconds' => 0, ); foreach (array_keys($diffs) as $interval) { while ($t2 >= ($t3 = strtotime("+1 ${interval}", $t1))) { $t1 = $t3; ++$diffs[$interval]; } } return $diffs; } ?> Expected result: ---------------- object(DateInterval)#3 (8) { ["y"]=> int(0) ["m"]=> int(2) ["d"]=> int(30) ["h"]=> int(0) ["i"]=> int(0) ["s"]=> int(0) ["invert"]=> int(0) ["days"]=> int(89) } object(DateTime)#1 (3) { ["date"]=> string(19) "2009-03-31 00:00:00" ["timezone_type"]=> int(3) ["timezone"]=> string(16) "America/Montreal" } object(DateTime)#1 (3) { ["date"]=> string(19) "2009-07-03 00:00:00" ["timezone_type"]=> int(3) ["timezone"]=> string(16) "America/Montreal" } Actual result: -------------- object(DateInterval)#3 (8) { ["y"]=> int(0) ["m"]=> int(3) ["d"]=> int(2) ["h"]=> int(0) ["i"]=> int(0) ["s"]=> int(0) ["invert"]=> int(0) ["days"]=> int(89) } object(DateTime)#1 (3) { ["date"]=> string(19) "2009-03-31 00:00:00" ["timezone_type"]=> int(3) ["timezone"]=> string(16) "America/Montreal" } object(DateTime)#1 (3) { ["date"]=> string(19) "2009-07-03 00:00:00" ["timezone_type"]=> int(3) ["timezone"]=> string(16) "America/Montreal" } -- Edit bug report at http://bugs.php.net/?id=49081&edit=1 -- Try a snapshot (PHP 5.2): http://bugs.php.net/fix.php?id=49081&r=trysnapshot52 Try a snapshot (PHP 5.3): http://bugs.php.net/fix.php?id=49081&r=trysnapshot53 Try a snapshot (PHP 6.0): http://bugs.php.net/fix.php?id=49081&r=trysnapshot60 Fixed in SVN: http://bugs.php.net/fix.php?id=49081&r=fixed Fixed in SVN and need be documented: http://bugs.php.net/fix.php?id=49081&r=needdocs Fixed in release: http://bugs.php.net/fix.php?id=49081&r=alreadyfixed Need backtrace: http://bugs.php.net/fix.php?id=49081&r=needtrace Need Reproduce Script: http://bugs.php.net/fix.php?id=49081&r=needscript Try newer version: http://bugs.php.net/fix.php?id=49081&r=oldversion Not developer issue: http://bugs.php.net/fix.php?id=49081&r=support Expected behavior: http://bugs.php.net/fix.php?id=49081&r=notwrong Not enough info: http://bugs.php.net/fix.php?id=49081&r=notenoughinfo Submitted twice: http://bugs.php.net/fix.php?id=49081&r=submittedtwice register_globals: http://bugs.php.net/fix.php?id=49081&r=globals PHP 4 support discontinued: http://bugs.php.net/fix.php?id=49081&r=php4 Daylight Savings: http://bugs.php.net/fix.php?id=49081&r=dst IIS Stability: http://bugs.php.net/fix.php?id=49081&r=isapi Install GNU Sed: http://bugs.php.net/fix.php?id=49081&r=gnused Floating point limitations: http://bugs.php.net/fix.php?id=49081&r=float No Zend Extensions: http://bugs.php.net/fix.php?id=49081&r=nozend MySQL Configuration Error: http://bugs.php.net/fix.php?id=49081&r=mysqlcfg