PHP DateTime accepting invalid date

Question

I'm having trouble using the PHP DateTime class, and more specifically the DateTime::createFromFormat().

I get a date from a string, then try to instanciate a DateTime object, using DateTime::createFromFormat(). But, when I give this function a date that cannot exist, it is still working, returning me a valid DateTime object, with a valid date, which isn't the date I gave it.

Code example :

$badDate = '2010-13-03';
$date = DateTime::createFromFormat('Y-m-d', $badDate);

var_dump($date);

/*
object(DateTime)#284 (3) {
["date"]=>
string(19) "2011-01-03 10:01:20"
["timezone_type"]=>
int(3)
["timezone"]=>
string(13) "Europe/Berlin"
}
*/

Any ideas? I really need a way to check date validity.

Thank you.

Edit:

I just found why, see my answer.

Answer 1

DateTime::createFromFormat doesn't throw exception/return false when the given date is impossible. It try to guess the expected date.

If you give it '2010-01-32' (as in Januar, 32th), it will return a DateTime object containing Februar, 1st (Januar 31th + 1 day). Must be logical... in some weird twisted way.

To check the validity, you must check the DateTime::getLastErrors() which contains warning, like for my case :

array(4) {
  ["warning_count"]=>
  int(1)
  ["warnings"]=>
  array(1) {
    [10]=>
    string(27) "The parsed date was invalid"
  }
  ["error_count"]=>
  int(0)
  ["errors"]=>
  array(0) {
  }
}

This behavior seems to come from the UNIX timestamp which PHP calculate, based on the year, month and date you give it (even if the date is invalid).

Answer 2

You have to make use of DateTime::getLastErrors() which will contain the error The parsed date was invalid.

$badDate = '2010-13-03';
$date = DateTime::createFromFormat('Y-m-d', $badDate);
if( DateTime::getLastErrors()['warning_count'] > 0 ){
 //not a correct date
}else{
 //correct date
 print $date->format('Y-m-d');
}