Doc #77202 [Com]: DateInterval compare unpredictable result

From: Date: Tue, 04 Dec 2018 23:04:14 +0000
Subject: Doc #77202 [Com]: DateInterval compare unpredictable result
References: 1  Groups: php.doc.bugs 
Request: Send a blank email to doc-bugs+get-16196@lists.php.net to get a copy of this message
Edit report at https://bugs.php.net/bug.php?id=77202&edit=1

 ID:                 77202
 Comment by:         a at b dot c dot de
 Reported by:        thomas dot wanka at gmx dot net
 Summary:            DateInterval compare unpredictable result
 Status:             Open
 Type:               Documentation Problem
 Package:            Date/time related
 Operating System:   Linux
 PHP Version:        7.2.12
 Block user comment: N
 Private report:     N

 New Comment:

See also Bug #74940


Previous Comments:
------------------------------------------------------------------------
[2018-11-26 11:23:37] a at b dot c dot de

Where did you read that > could be used to compare objects in the first place?



What does happen is that if you do a debugging dump of a DateTime object it creates a bunch of
additional properties.
<?php
$old = DateTime::createFromFormat('Y-m-d H:i:s', '2018-11-26 09:29:00'); 
$now = new DateTime('now',new DateTimeZone('Europe/Berlin'));
$actualDiff = $now->diff($old);

echo "Weekday: ", $actualDiff->weekday;
echo "\n";
print_r($actualDiff);
echo "\n";
echo "Weekday: ", $actualDiff->weekday;

------------------------------------------------------------------------
[2018-11-26 08:53:54] thomas dot wanka at gmx dot net

Description:
------------
The result if compare operator on two DateInterval objects is unpredictable.
See code in the "test script" section:
the result of the if() statement depends on the code before. If, for instance, you print the
DateInterval, the internal structure seems to change, and the result is correct. Otherwise, the
result is not correct. The system should output an error or a warning if the compare operater is not
fully implemented.

Test script:
---------------
<?php
$old = DateTime::createFromFormat('Y-m-d H:i:s', '2018-11-26 09:29:00'); 
// constant here for demo only, i read datetime field from database
$now = new DateTime('now',new DateTimeZone('Europe/Berlin'));
$maxdiff = new DateInterval('PT30M');
$actualDiff = $now->diff($old);

// echo "<pre>"; print_r($now); echo "</pre><br />";
// echo "<pre>"; print_r($maxdiff ); echo "</pre><br />";

if ($actualDiff>$maxDiff) echo "time is up" else echo "just wait";
?>


Expected result:
----------------
throw an error if an nvalid operator ist used 
minimum request: add information about this behauviour into documentation of DateInterval

Actual result:
--------------
operator is performed, result is unpredictable


------------------------------------------------------------------------



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Edit this bug report at https://bugs.php.net/bug.php?id=77202&edit=1


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