#40691 [Opn->Bgs]: Incorrect results of DateTime equality check

ID: 40691 Updated by: iliaa@php.net Reported By: hans at velum dot net -Status: Open +Status: Bogus Bug Type: Date/time related Operating System: Gentoo Linux PHP Version: 5.2.1 New Comment: Thank you for taking the time to write to us, but this is not a bug. Please double-check the documentation available at http://www.php.net/manual/ and the instructions on how to report a bug at http://bugs.php.net/how-to-report.php This is not a bug. The date extension does not provide (or is intended) for the purpose of comparing two date objects. You could have the same date in the object by different properties initialized due to the way the object was created. As I've said earlier the most reliable way to compare two dates would be to convert them to unix timestamps and then compare the two. Previous Comments: ------------------------------------------------------------------------ [2007-03-03 21:36:07] dzuelke at gmail dot com hans at velum dot net is correct, I just stumbled over the same issue. It definitely smells like a bug, nothing bogus here. The stored date is a property of the object, but not compared properly as it should according to the rules described at http://php.net/manual/en/ language.oop5.php. Probably because it's not possible to pull the individual parts of a date (day, month, year etc) from a DateTime instance, but that's a different story... ------------------------------------------------------------------------ [2007-03-03 19:47:15] hans at velum dot net This is not bogus. Maybe "won't fix" but definitely not bogus. Please note that I am quite familiar with object comparison in PHP. The documenation says: "When using the comparison operator (==), object variables are compared in a simple manner, namely: Two object instances are equal if they have the same attributes and values, and are instances of the same class." Indeed, AS I POINTED OUT IN THE DESCRIPTION, other built-in objects in PHP demonstrate the correct/expected behavior: $a = new Exception("foo"); $b = new Exception("bar"); $c = new Exception("foo"); var_export($a == $b); // Outputs: FALSE var_export($a == $c); // Outputs: TRUE A DateTime object have very obvious properties (namely the date/time value contained, possibly time zone of other info specified). The equality check (NOT IDENTITY CHECK) should be comparing those values, as apparently it does for Exception. ------------------------------------------------------------------------ [2007-03-03 15:55:40] iliaa@php.net Thank you for taking the time to write to us, but this is not a bug. Please double-check the documentation available at http://www.php.net/manual/ and the instructions on how to report a bug at http://bugs.php.net/how-to-report.php Read on object comparison in PHP, what you are attempting will not work. if you want to compare 2 dates, convert them to unix timestamps first. ------------------------------------------------------------------------ [2007-03-02 15:43:14] hans at velum dot net Description: ------------ The equality check (==) for DateTime objects does not actually check the properties of the object (i.e. the internally stored date). This is very counter-intuitive as it does not follow the behavior of user-created objects or even other internal PHP objects like Exception. Reproduce code: --------------- $d1 = new DateTime("2001-01-01"); $d2 = new DateTime("2007-02-28"); print "DateTime Equal? " . var_export($d1 == $d2, true) . "\n"; Expected result: ---------------- DateTime Equal? false Actual result: -------------- DateTime Equal? true ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/?id=40691&edit=1