#50682 [Bgs]: strtotime producing incorrect result

ID: 50682 Updated by: rasmus@php.net Reported By: keefeg at gmail dot com Status: Bogus Bug Type: Date/time related Operating System: FreeBSD 6.2 PHP Version: 5.2.12 New Comment: This isn't something we made up. We are simply following the GNU strtotime convention as it is implemented by your command line date utility and many others as well. It is described here: http://www.gnu.org/software/tar/manual/html_node/Relative-items-in- date-strings.html#SEC120 Note the second last paragraph that talks about the fuzz in units. Whether this should have been done this way or not is debatable, but it is a consistent convention and we don't want to stray from that. Previous Comments: ------------------------------------------------------------------------ [2010-01-07 01:37:43] keefeg at gmail dot com I understand your explanation, but the results still seem incorrect. Under reasonable circumstances even programmers shouldn't have to consider "last month" to be equal to "this month." In the context of "last month", it should first decrement the month, and then if that particular day (31st of November) does not exist, it should then decrement the day until it reaches a valid day (30th of November). The way it is now breaks programs in a non-obvious way. I use that code to daily make a list of archive files to "keep" (now, -1 month, -2 month, -3 month) and on the 31st of December it ended up deleting the november file because it thought "-1 month" was December. I'll work around using the 1st of the month, but it at least merits a warning in the documentation. Thanks for PHP, it's incredibly useful! ------------------------------------------------------------------------ [2010-01-06 20:53:58] rasmus@php.net That's because you are asking for the same day last month which doesn't exist since November doesn't have 31 days. November 31 gets normalized to Dec 1. If you are using last/next make sure you feed it a recurring starting point. Like the 1st of the sequence, in this case the 1st of the month. ------------------------------------------------------------------------ [2010-01-06 20:28:57] keefeg at gmail dot com Description: ------------ strtotime does not handle the "last month" parameter correctly all the time. Reproduce code: --------------- --- From manual page: function.strtotime#Description --- $ny = strtotime("31 December 2009"); echo "this month: " . date('Ym', strtotime("now", $ny)) . "\n"; echo "last month: " . date('Ym', strtotime("last month", $ny)) . "\n"; Expected result: ---------------- I would like it to produce this result: this month: 200912 last month: 200911 Actual result: -------------- It prints this result: this month: 200912 last month: 200912 ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/?id=50682&edit=1