Bug #60212 [Opn->Fbk]: Unexpected behaviour while adding or subtracting relative time with strtotime

Edit report at https://bugs.php.net/bug.php?id=60212&edit=1 ID: 60212 Updated by: rasmus@php.net Reported by: reetz at krumedia dot de Summary: Unexpected behaviour while adding or subtracting relative time with strtotime -Status: Open +Status: Feedback Type: Bug Package: Date/time related Operating System: Linux version 2.6.32-5-amd64 PHP Version: 5.3.8 Block user comment: N Private report: N New Comment: php -a Interactive shell php > echo strtotime('-1 minute', strtotime('2011-10-30 01:00 UTC')); 1319936340 php > echo -60 + strtotime('2011-10-30 01:00 UTC'); 1319936340 Looks the same for me both in 5.3.8 and 5.4.0 Previous Comments: ------------------------------------------------------------------------ [2011-11-03 18:16:11] reetz at krumedia dot de Please take the time and read my report properly . I am well aware of "DAYLIGHT SAVING TIME". I am even aware that not all countries have their DST on the same date, into the same direction or at all. For example Australian (except NT, WA and QLD) Standard Time: 3 April 2011 to 2 October 2011 Summer Time : 2 October 2011 to 1 April 2012 European Summer Time : 27 March 2011 to 30 October 2011 Standard Time: 30 October 2011 to 25 March 2012 Rusia : DST no longer in use Saudi Arabia : DST never used So, please do not use such a dismissive language. I was using UTC values. There is no room for DST interpretation in UTC. My whole application calculates in UTC. All time conversions are done with strtotime('.... UTC') and gmdate('Y-m-d H:i:s \U\T\C') because of DST. I was supplying an DST-free Time. I was already searching for a "strtotime('-1 minute UTC',..)", no such luck! Why is php -r "echo strtotime('-1 minute', strtotime('2011-10-30 01:00 UTC'));" not the same as php -r "echo -60 + strtotime('2011-10-30 01:00 UTC');" The first returns 1319932740 and the second returns 1319936340 while strtotime('2011-10-30 01:00 UTC') is 1319936400, but (1319936400 - 1319932740) equals 3660, that's one hour and 1 minute. Not one minute as requested! >>>Taken out of the manual: strtotime ".... will try to parse that format into a Unix timestamp (the number of seconds since January 1 1970 00:00:00 UTC)" Please enlighten me ! Why should "1319932740" be the result of php -r "echo strtotime('-1 minute', 1319936400);" even IF my operation systems time zone is "Europe/Berlin". The integer-value of a Unix-Timestamp has no Timezone. That is the whole point of Unix-timestamp. Why should -1 Minute of an integer value (of any date) be relevant to DST. The input is an Unix Timestamp, the output is an Unix Timestamp, the difference is 60 seconds. Where is the DST in this calculation? Really, tell me. The answer should be easy for someone with so much "more sense". Sincerely Yours Michael Reetz P.S. sorry for that last sentence, I am feeling better now. ------------------------------------------------------------------------ [2011-11-03 16:53:51] anon at anon dot anon No matter how many times I see these reports, it still absolutely boggles my mind that so many PROGRAMMERS -- people you'd really think were capable of more sense, can't spot DAYLIGHT SAVING TIME even when it's staring them right in the face. ------------------------------------------------------------------------ [2011-11-03 15:07:17] reetz at krumedia dot de Description: ------------ This problem only exists while using a time zone other than UTC, in my case "Europe/Berlin". I have to do relative time calculations and got an unexpected behaviour. I was "missing" one hour of data and some data was misplaced. First I assumed, I had forgotten an "UTC" or was using an "date" instead of "gmdate". Yet it was none of the former. As it turns out, strtotime is doing something extremely unexpected or even wrong. The output consists of five columns, each contains timestamps formatted with "d H:i \U\T\C" - sUnexpectedTimePrevious // minus one minute by strtotime - sTimePrevious // minus one minute as it should be - sTimeNow // - sTimeNext // plus one minute as it should be - sUnexpectedTimeNext // plus one minute by strtotime Lines with errors are marked with an exclamation marks. One line is of particular interest: ! 29 23:59 UTC | 30 00:59 UTC | 30 01:00 UTC | 30 01:01 UTC | 30 01:01 UTC Instead of one hour into the future it's now suddenly two one into the past. For the record, yes I had done a search before submitting this report. I found #54799 and #53370, yet I feel that the example I submitted might help analysing the problem. I am well aware that I could solve my problem by simply switching the default time zone to "UTC". But this is only solving a symptom, not the real problem. sincerely yours Michael Reetz Test script: --------------- //date_default_timezone_set('UTC'); // no problem date_default_timezone_set('Europe/Berlin'); // big problem $iCurrent = strtotime('2011-10-29 23:55:00 UTC'); $iEnd = strtotime('2011-10-30 01:05:00 UTC'); while ($iCurrent <= $iEnd){ $sTimeNow = gmdate('d H:i \U\T\C', $iCurrent ); $sTimePrevious = gmdate('d H:i \U\T\C', -60 + $iCurrent ); $sTimeNext = gmdate('d H:i \U\T\C', 60 + $iCurrent ); $sUnexpectedTimePrevious = gmdate('d H:i \U\T\C', strtotime('- 1 minute',$iCurrent)); $sUnexpectedTimeNext = gmdate('d H:i \U\T\C', strtotime('+ 1 minute',$iCurrent)); echo ($sUnexpectedTimePrevious != $sTimePrevious) ? '!':' '; echo " $sUnexpectedTimePrevious | $sTimePrevious | $sTimeNow | $sTimeNext | $sUnexpectedTimeNext "; echo ($sUnexpectedTimeNext != $sTimeNext) ? '!':' '; echo "\n"; $iCurrent += 60; } Expected result: ---------------- // created with : date_default_timezone_set('UTC'); 29 23:54 UTC | 29 23:54 UTC | 29 23:55 UTC | 29 23:56 UTC | 29 23:56 UTC 29 23:55 UTC | 29 23:55 UTC | 29 23:56 UTC | 29 23:57 UTC | 29 23:57 UTC 29 23:56 UTC | 29 23:56 UTC | 29 23:57 UTC | 29 23:58 UTC | 29 23:58 UTC 29 23:57 UTC | 29 23:57 UTC | 29 23:58 UTC | 29 23:59 UTC | 29 23:59 UTC 29 23:58 UTC | 29 23:58 UTC | 29 23:59 UTC | 30 00:00 UTC | 30 00:00 UTC 29 23:59 UTC | 29 23:59 UTC | 30 00:00 UTC | 30 00:01 UTC | 30 00:01 UTC 30 00:00 UTC | 30 00:00 UTC | 30 00:01 UTC | 30 00:02 UTC | 30 00:02 UTC 30 00:01 UTC | 30 00:01 UTC | 30 00:02 UTC | 30 00:03 UTC | 30 00:03 UTC [.. skipped several lines ..] 30 00:57 UTC | 30 00:57 UTC | 30 00:58 UTC | 30 00:59 UTC | 30 00:59 UTC 30 00:58 UTC | 30 00:58 UTC | 30 00:59 UTC | 30 01:00 UTC | 30 01:00 UTC 30 00:59 UTC | 30 00:59 UTC | 30 01:00 UTC | 30 01:01 UTC | 30 01:01 UTC 30 01:00 UTC | 30 01:00 UTC | 30 01:01 UTC | 30 01:02 UTC | 30 01:02 UTC 30 01:01 UTC | 30 01:01 UTC | 30 01:02 UTC | 30 01:03 UTC | 30 01:03 UTC 30 01:02 UTC | 30 01:02 UTC | 30 01:03 UTC | 30 01:04 UTC | 30 01:04 UTC 30 01:03 UTC | 30 01:03 UTC | 30 01:04 UTC | 30 01:05 UTC | 30 01:05 UTC 30 01:04 UTC | 30 01:04 UTC | 30 01:05 UTC | 30 01:06 UTC | 30 01:06 UTC Actual result: -------------- // created with : date_default_timezone_set('Europe/Berlin'); 29 23:54 UTC | 29 23:54 UTC | 29 23:55 UTC | 29 23:56 UTC | 29 23:56 UTC 29 23:55 UTC | 29 23:55 UTC | 29 23:56 UTC | 29 23:57 UTC | 29 23:57 UTC 29 23:56 UTC | 29 23:56 UTC | 29 23:57 UTC | 29 23:58 UTC | 29 23:58 UTC 29 23:57 UTC | 29 23:57 UTC | 29 23:58 UTC | 29 23:59 UTC | 29 23:59 UTC 29 23:58 UTC | 29 23:58 UTC | 29 23:59 UTC | 30 00:00 UTC | 30 01:00 UTC ! 29 23:59 UTC | 29 23:59 UTC | 30 00:00 UTC | 30 00:01 UTC | 30 01:01 UTC ! ! 30 01:00 UTC | 30 00:00 UTC | 30 00:01 UTC | 30 00:02 UTC | 30 01:02 UTC ! ! 30 01:01 UTC | 30 00:01 UTC | 30 00:02 UTC | 30 00:03 UTC | 30 01:03 UTC ! [.. skipped several lines ..] ! 30 01:57 UTC | 30 00:57 UTC | 30 00:58 UTC | 30 00:59 UTC | 30 01:59 UTC ! ! 30 01:58 UTC | 30 00:58 UTC | 30 00:59 UTC | 30 01:00 UTC | 30 02:00 UTC ! ! 29 23:59 UTC | 30 00:59 UTC | 30 01:00 UTC | 30 01:01 UTC | 30 01:01 UTC 30 01:00 UTC | 30 01:00 UTC | 30 01:01 UTC | 30 01:02 UTC | 30 01:02 UTC 30 01:01 UTC | 30 01:01 UTC | 30 01:02 UTC | 30 01:03 UTC | 30 01:03 UTC 30 01:02 UTC | 30 01:02 UTC | 30 01:03 UTC | 30 01:04 UTC | 30 01:04 UTC 30 01:03 UTC | 30 01:03 UTC | 30 01:04 UTC | 30 01:05 UTC | 30 01:05 UTC 30 01:04 UTC | 30 01:04 UTC | 30 01:05 UTC | 30 01:06 UTC | 30 01:06 UTC ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=60212&edit=1