Bug #50055 [Csd]: indeterminant DateInterval does not subtract correctly

Edit report at http://bugs.php.net/bug.php?id=50055&edit=1 ID: 50055 Updated by: jani@php.net Reported by: jennifer dot kimball at nrc dot ca Summary: indeterminant DateInterval does not subtract correctly Status: Closed Type: Bug Package: Date/time related Operating System: Solaris 10 PHP Version: 5.3.0 Assigned To: derick New Comment: Derick had a small typo in his commit, here's the commit: Revision: http://svn.php.net/viewvc?view=revision&revision=295924 Previous Comments: ------------------------------------------------------------------------ [2010-03-07 14:55:13] derick@php.net This bug has been fixed in SVN. Snapshots of the sources are packaged every three hours; this change will be in the next snapshot. You can grab the snapshot at http://snaps.php.net/. Thank you for the report, and for helping us make PHP better. Fixed by making this throw a warning, as it's not supported to use "special" relative time strings with ->sub(). ------------------------------------------------------------------------ [2009-11-02 16:01:31] derick@php.net There is a bug here, but the only thing would be that "sub" can *not* be used with relative time strings such as "last ... of". It is logically too complicated (for people) to easily reverse strings like that. Such an attempt should throw an exception/error instead though. ------------------------------------------------------------------------ [2009-11-02 15:07:18] jennifer dot kimball at nrc dot ca Description: ------------ The logical behaviour of a DateInterval created with the "next" keyword, when subtracted from a DateTime, should be to use "last" instead of "next" in the calculation (and vice versa). Instead, it appears that DateIntervals created with "next" or "last" keywords cannot be subtracted from DateTimes with any accuracy. A DateTime results from the operation but has an unexpected value. Reproduce code: --------------- //positive DateInterval $da1=date_create(); $ds1=date_create(); $i=DateInterval::createFromDateString('third Tuesday of next month'); echo $da1->format('Y-m-d'); echo date_add($da1,$i)->format('Y-m-d');//works echo date_sub($ds1,$i)->format('Y-m-d');//fails with weird date //negative DateInterval $da2=date_create(); $ds2=date_create(); $i2=DateInterval::createFromDateString('third Tuesday of last month'); echo $da2->format('Y-m-d'); echo date_add($da2,$i2)->format('Y-m-d');//works echo date_sub($ds2,$i2)->format('Y-m-d');//fails with weird date Expected result: ---------------- 2009-11-02 //today 2009-12-15 //third Tuesday of December 2009-10-20 //third Tuesday of October 2009-11-02 //today 2009-10-20 //third Tuesday of October 2009-12-15 //third Tuesday of December Actual result: -------------- 2009-11-02 //today 2009-12-15 //third Tuesday of December 2009-09-18 //third Friday of September 2009-11-02 //today 2009-10-20 //third Tuesday of October 2009-11-18 //third Wednesday of November ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/bug.php?id=50055&edit=1