wp_exif_date2ts throws notice on slash formatted date

[domainsupport]

When an image has an exif date in the format ...

YYYY/MM/DD HH:MM:SS

... rather than ...

YYYY:MM:DD HH:MM:SS

... which is happening more and more I have noticed, the following PHP notices are thrown ...

PHP Notice: Undefined offset: 1 in /var/www/tourist.org.uk/html/wp-admin/includes/image.php on line 710
PHP Notice: Undefined offset: 2 in /var/www/tourist.org.uk/html/wp-admin/includes/image.php on line 710

I think there are a lot of assumptions being made in wp_exif_date2ts() and I believe that a preg_match check like ...

<?php
if (preg_match('/^(?>\d){4}[:|\/](?>\d){2}[:|\/](?>\d){2} (?>\d){2}:(?>\d){2}:(?>\d){2}$/', $str)) {

// Process and return exif date

} else {
return false;
}

... should be done instead.

This is related to ticket 48204