DateTime::diff miscalculation is same time zone of different type #8730

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1. jabelli

   added

   Bug

   Status: Needs Triage

   on Jun 8, 2022
2. cmb69

   added

   Extension: date

   on Jun 8, 2022
3. cmb69

   assigned

   derickr

   on Jun 8, 2022
4. hormus commented on Jun 12, 2022

   

   hormus

   on Jun 12, 2022

   Last edited by hormus

   More actions

   Since php 8.1.0 diff compares time zone type equality, in some circumstances although type 1 (numeric time zone) or type 3 (literal time zone) may produce a date with daylight saving time setting. (it means that although type 3 time zone converted to numerical sequence of seconds is exactly the same as type 1 time zone, as php decides whether to consider daylight saving time or not).

   https://wiki.php.net/rfc/datetime_and_daylight_saving_time

   It is difficult to document and too much information is confusing, certainly a good encoding is to use the same type timezone for the two date objects requested by diff.
   This change https://bugs.php.net/bug.php?id=81458

   $foo is big to $bar, inverter to $bar->diff($foo));

   <?php
   
   date_default_timezone_set('America/New_York');
   $foo = new DateTime('2022-06-08 09:15:00', new DateTimeZone('-04:00'));
   $bar = new DateTime('2022-06-08 09:15:00', new DateTimeZone('America/New_York'));
   var_dump($foo->format('U'), $bar->format('U'), $bar->diff($foo));
   /*string(10) "1654694100"
   string(10) "1654694100"
   object(DateInterval)#3 (16) {
     ["y"]=>
     int(0)
     ["m"]=>
     int(0)
     ["d"]=>
     int(0)
     ["h"]=>
     int(1)
     ["i"]=>
     int(0)
     ["s"]=>
     int(0)
     ["f"]=>
     float(0)
     ["weekday"]=>
     int(0)
     ["weekday_behavior"]=>
     int(0)
     ["first_last_day_of"]=>
     int(0)
     ["invert"]=>
     int(0)
     ["days"]=>
     int(0)
     ["special_type"]=>
     int(0)
     ["special_amount"]=>
     int(0)
     ["have_weekday_relative"]=>
     int(0)
     ["have_special_relative"]=>
     int(0)
   }*/
   ?>

   Note* US/Eastern https://www.php.net/manual/en/timezones.others.php

   before php 8.1 the comparison was for the date represented by the conversion to UTC

   <?php
   
   date_default_timezone_set('America/New_York');
   $foo = new DateTime('2022-06-08 09:15:00', new DateTimeZone('-04:00'));
   $bar = new DateTime('2022-06-08 09:15:00', new DateTimeZone('America/New_York'));
   var_dump($foo->format('U'), $bar->format('U'), $bar->diff($foo)); //Before php 8.1.0 2022-06-08 13:15:00 - 2022-06-08 13:15:00 = 0
   
   $foo = new DateTime('2022-06-08 09:15:00', new DateTimeZone('America/New_York'));
   $bar = new DateTime('2022-06-08 09:15:00', new DateTimeZone('America/New_York'));
   var_dump($foo->format('U'), $bar->format('U'), $bar->diff($foo)); //from php 8.1.0 2022-06-08 9:15:00 - 2022-06-08 9:15:00 = 0
   
   ?>
5. derickr

   added

   Status: Fixed in Third Party Library

   and removed

   Status: Needs Triage

   on Jun 17, 2022
6. derickr commented on Jun 17, 2022

   

   derickr

   on Jun 17, 2022

   Member

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   Fixed in timelib: derickr/timelib#128, and the fix will make it into PHP once timelib gets merged again.

   👍React with 👍1Reacted by AnrDaemon
7. ToshY commented on Jul 20, 2022

   

   ToshY

   on Jul 20, 2022

   Last edited by ToshY

   More actions

   @derickr Could you give an estimation on when this (timelib fix) actually gets merged?
8. derickr

   added a commit that references this issue on Jul 21, 2022

   Fixed phpGH-8730: DateTime::diff miscalculation is same time zone of …

   ...

   This issue will close once commit cc9c577 is merged into the 'master' branch.

   cc9c577
9. derickr

   closed this as completedin cc9c577on Jul 21, 2022
10. derickr commented on Jul 21, 2022

    

    derickr

    on Jul 21, 2022

    Member

    More actions

    Just now :-)

    👍React with 👍1Reacted by ToshY
11. jabelli commented on Jul 21, 2022

    

    jabelli

    on Jul 21, 2022

    Author

    More actions

    Create new for 8.2 or reopen this one? I just tested 8.2β1:

    object(DateInterval)#3 (10) {
      ["y"]=>
      int(-1)
      ["m"]=>
      int(11)
      ["d"]=>
      int(30)
      ["h"]=>
      int(23)
      ["i"]=>
      int(0)
      ["s"]=>
      int(0)
      ["f"]=>
      float(0)
      ["invert"]=>
      int(0)
      ["days"]=>
      int(0)
      ["from_string"]=>
      bool(false)
    }