ID: 20382 Comment by: pierre dot baudracco at aliacom dot fr Reported By: nickj-phpbugs at nickj dot org Status: Verified Bug Type: Date/time related Operating System: All PHP Version: 4.3.0-dev New Comment:
This bug is reappearing this week from monday 2003-10-20. Which is a week having a daylight saving transition (this week-end). Previous Comments: ------------------------------------------------------------------------ [2003-04-06 18:47:03] scottmacvicar at ntlworld dot com This is a DST problem by the looks of it. The specific dates mentioned are when DST takes effect which is the last sunday in March. ------------------------------------------------------------------------ [2002-11-12 19:46:28] nickj-phpbugs at nickj dot org OK, I decided that was needed was some kind of automated testing, so I wrote it: ============================================ #!/root/php4-200211122230 -q <?php // report any errors at all error_reporting (E_ALL); // pass a date, supply a strtotime modifier, and get a date back function getDateWithModifier($date, $modifier) { list ($year, $month, $day) = explode ("-",$date); $starting_timestamp = mktime (1,1,1,$month,$day,$year); $timestamp_with_modifier = strtotime ($modifier, $starting_timestamp); return date("Y-n-j", $timestamp_with_modifier); } /* ** @desc: for the specified date, will find the date for the desired day of the ** week that is also in the same week. Does NOT use 'strtotime' */ function getDayOfTheWeekFromDate($date, $desired_day_of_week) { // weekdays - note special case for sundays (7, not 0), so as to treat as end of week, not start $weekdays = array ("Sunday" => 7, "Monday" => 1, "Tuesday" => 2, "Wednesday" => 3, "Thursday" => 4, "Friday" => 5, "Saturday" => 6); // convert into a number $desired_day_of_week_number = $weekdays[$desired_day_of_week]; // see what day we have currently list ($year, $month, $day) = explode ("-",$date); $date_day_of_week = date("w", mktime (17,17,17,$month,$day,$year)); $new_day = $day+(($desired_day_of_week_number-$date_day_of_week)+7) % 7; return date("Y-n-j", mktime (17,17,17,$month,$new_day,$year)); } // run an automated test to compare the output of these two functions, and complain if they differ for ($i=1; $i<1000; $i++) { $date = date("Y-n-j", mktime (17,17,17,1,$i,1999)); $strtotime_date = getDateWithModifier($date, "Monday"); $other_date = getDayOfTheWeekFromDate($date, "Monday"); if ($strtotime_date != $other_date) { print "Discrepancy for $date - results were $strtotime_date vs $other_date\n"; } } print "PHP version: " . phpversion(). "<br>\n"; ?> ============================================ Here's the output that I get: ============================================ [EMAIL PROTECTED] tmp]# ./automated-date-test.php Discrepancy for 1999-3-23 - results were 1999-3-28 vs 1999-3-29 Discrepancy for 1999-3-24 - results were 1999-3-28 vs 1999-3-29 Discrepancy for 1999-3-25 - results were 1999-3-28 vs 1999-3-29 Discrepancy for 1999-3-26 - results were 1999-3-28 vs 1999-3-29 Discrepancy for 1999-3-27 - results were 1999-3-28 vs 1999-3-29 Discrepancy for 1999-3-28 - results were 1999-3-28 vs 1999-3-29 Discrepancy for 2000-3-21 - results were 2000-3-26 vs 2000-3-27 Discrepancy for 2000-3-22 - results were 2000-3-26 vs 2000-3-27 Discrepancy for 2000-3-23 - results were 2000-3-26 vs 2000-3-27 Discrepancy for 2000-3-24 - results were 2000-3-26 vs 2000-3-27 Discrepancy for 2000-3-25 - results were 2000-3-26 vs 2000-3-27 Discrepancy for 2000-3-26 - results were 2000-3-26 vs 2000-3-27 Discrepancy for 2001-3-20 - results were 2001-3-25 vs 2001-3-26 Discrepancy for 2001-3-21 - results were 2001-3-25 vs 2001-3-26 Discrepancy for 2001-3-22 - results were 2001-3-25 vs 2001-3-26 Discrepancy for 2001-3-23 - results were 2001-3-25 vs 2001-3-26 Discrepancy for 2001-3-24 - results were 2001-3-25 vs 2001-3-26 Discrepancy for 2001-3-25 - results were 2001-3-25 vs 2001-3-26 PHP version: 4.3.0-dev<br> [EMAIL PROTECTED] tmp]# ============================================ In other words, the result for these 6 days of the year consistently appears to be wrong. (I suppose I should be glad that the very first date I choose to test this function with just by fluke happened to be one of those 6 days, as opposed to causing mysterious problems later!) Does anyone else get any results that appear incorrect on running this script? ------------------------------------------------------------------------ [2002-11-12 18:10:27] nickj-phpbugs at nickj dot org Happy to comply. I tried it with the CVS snapshot (php4-200211122230), output was: ============================================================= [EMAIL PROTECTED] tmp]# ./script.php <hr> from 2001-3-17, goto monday: 2001-3-19; should be 2001-3-19.<br> from 2001-3-18, goto monday: 2001-3-19; should be 2001-3-19.<br> from 2001-3-19, goto monday: 2001-3-19; should be 2001-3-19.<br> from 2001-3-20, goto monday: 2001-3-25; should be 2001-3-26 ###.<br> from 2001-3-21, goto monday: 2001-3-25; should be 2001-3-26 ###.<br> from 2001-3-22, goto monday: 2001-3-25; should be 2001-3-26 ###.<br> from 2001-3-23, goto monday: 2001-3-25; should be 2001-3-26 ###.<br> from 2001-3-24, goto monday: 2001-3-25; should be 2001-3-26 ###.<br> from 2001-3-25, goto monday: 2001-3-25; should be 2001-3-26 ###.<br> from 2001-3-26, goto monday: 2001-3-26; should be 2001-3-26.<br> from 2001-3-27, goto monday: 2001-4-2 ; should be 2001-4-2.<br> <hr> PHP version: 4.3.0-dev<br> [EMAIL PROTECTED] tmp]# ============================================================= i.e. same problem. The location of the php command-line executable appears to have changed to 'sapi/cli/php' (in the PHP 4.2.3 build process the executable just ends up in the root of the source directory), so this was what I used, hope this is OK. Here is some more info related to the problem that may or may not be relevant: * This machine and I are located in Sydney, Australia. The machine's timezone as shown in 'timeconfig' is set of "Australia/Sydney", and "Hardware clock set to GMT" is shown turned off. Output of the 'date' command looks like this: "Wed Nov 13 10:40:22 EST 2002". Sydney is (depending on daylight savings) around GMT + 10 hours. * I've found today that there was a daylight savings transition for this timezone in that week. From: http://www.dstc.qut.edu.au/DST/marg/daylight.html - "[Daylight savings] ends at 3am on Sunday 25 March 2001. Clocks should be turned back one hour to read 2am (Australian Eastern Standard Time)." * Since there was a daylight savings transition, I've now tried various parameters to the 'mktime' line, in case the hour/minute/second parameters chosen were causing problems because they were too close to the time transition. I've tried the following parameters, all of which produce the same incorrect result: - mktime (23,23,23,$month,$day,$year); - mktime (15,15,15,$month,$day,$year); - mktime (10,10,10,$month,$day,$year); - mktime (5,5,5,$month,$day,$year); - mktime (1,1,1,$month,$day,$year); ------------------------------------------------------------------------ [2002-11-12 06:17:41] [EMAIL PROTECTED] Please try using this CVS snapshot: http://snaps.php.net/php4-latest.tar.gz For Windows: http://snaps.php.net/win32/php4-win32-latest.zip Your script produces the expected dates for me with latest CVS snapshot. Please give try it out. ------------------------------------------------------------------------ [2002-11-12 02:11:16] nickj-phpbugs at nickj dot org Strtotime() appears to produce incorrect output under some circumstances - specifically when wanting the date of a particular day of the week day of the week from a given starting date. For example, using 2001-3-20 as a starting point, we want the date for the next Monday. The correct answer is the 26th, but the result produced is the 25th (a Sunday). The correct result is given sometimes, so this appears to depend on the input. A sample script to illustrate: ======================================================= #!/root/php-4.2.3 -q <?php // report any errors at all error_reporting (E_ALL); // pass a date, supply a strtotime modifier, and get a date back function getDateWithModifier($date, $modifier) { list ($year, $month, $day) = explode ("-",$date); $starting_timestamp = mktime (10,10,10,$month,$day,$year); $timestamp_with_modifier = strtotime ($modifier, $starting_timestamp); return date("Y-n-j", $timestamp_with_modifier); } print "<hr>\n"; print "from 2001-3-17, goto monday: " . getDateWithModifier("2001-3-17", "Monday") . "; should be 2001-3-19.<br>\n"; print "from 2001-3-18, goto monday: " . getDateWithModifier("2001-3-18", "Monday") . "; should be 2001-3-19.<br>\n"; print "from 2001-3-19, goto monday: " . getDateWithModifier("2001-3-19", "Monday") . "; should be 2001-3-19.<br>\n"; print "from 2001-3-20, goto monday: " . getDateWithModifier("2001-3-20", "Monday") . "; should be 2001-3-26 ###.<br>\n"; print "from 2001-3-21, goto monday: " . getDateWithModifier("2001-3-21", "Monday") . "; should be 2001-3-26 ###.<br>\n"; print "from 2001-3-22, goto monday: " . getDateWithModifier("2001-3-22", "Monday") . "; should be 2001-3-26 ###.<br>\n"; print "from 2001-3-23, goto monday: " . getDateWithModifier("2001-3-23", "Monday") . "; should be 2001-3-26 ###.<br>\n"; print "from 2001-3-24, goto monday: " . getDateWithModifier("2001-3-24", "Monday") . "; should be 2001-3-26 ###.<br>\n"; print "from 2001-3-25, goto monday: " . getDateWithModifier("2001-3-25", "Monday") . "; should be 2001-3-26 ###.<br>\n"; print "from 2001-3-26, goto monday: " . getDateWithModifier("2001-3-26", "Monday") . "; should be 2001-3-26.<br>\n"; print "from 2001-3-27, goto monday: " . getDateWithModifier("2001-3-27", "Monday") . " ; should be 2001-4-2.<br>\n"; print "<hr>\n"; print "PHP version: " . phpversion(). "<br>\n"; ?> ======================================================= Produces this output: ======================================================= [EMAIL PROTECTED] tmp]# ./script.php <hr> from 2001-3-17, goto monday: 2001-3-19; should be 2001-3-19.<br> from 2001-3-18, goto monday: 2001-3-19; should be 2001-3-19.<br> from 2001-3-19, goto monday: 2001-3-19; should be 2001-3-19.<br> from 2001-3-20, goto monday: 2001-3-25; should be 2001-3-26 ###.<br> from 2001-3-21, goto monday: 2001-3-25; should be 2001-3-26 ###.<br> from 2001-3-22, goto monday: 2001-3-25; should be 2001-3-26 ###.<br> from 2001-3-23, goto monday: 2001-3-25; should be 2001-3-26 ###.<br> from 2001-3-24, goto monday: 2001-3-25; should be 2001-3-26 ###.<br> from 2001-3-25, goto monday: 2001-3-25; should be 2001-3-26 ###.<br> from 2001-3-26, goto monday: 2001-3-26; should be 2001-3-26.<br> from 2001-3-27, goto monday: 2001-4-2 ; should be 2001-4-2.<br> <hr> PHP version: 4.2.3<br> [EMAIL PROTECTED] tmp]# ======================================================== Expected output: The 6 lines with "###" are expected to produce the indicated output, but do not. Problem was noticed today in PHP 4.06, and then verified as being reproducible in PHP 4.2.3 (same output). PHP 4.2.3 configured with: ./configure --with-mysql --enable-xml --enable-wddx ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/?id=20382&edit=1