TYPO3 Core

The DateViewHelper only supports DateTime objects or Unix Timestamps, but instead of checking for a concrete DateTime object it should support the DateTimeInterface. The way it is now, you can't work with \DateTimeImmutable objects.

Relevant code:

        if (!$date instanceof \DateTime) {
            try {
                $base = $base instanceof \DateTime ? $base->format('U') : strtotime((MathUtility::canBeInterpretedAsInteger($base) ? '@' : '') . $base);
                $dateTimestamp = strtotime((MathUtility::canBeInterpretedAsInteger($date) ? '@' : '') . $date, $base);
                $date = new \DateTime('@' . $dateTimestamp);
                $date->setTimezone(new \DateTimeZone(date_default_timezone_get()));
            } catch (\Exception $exception) {
                throw new Exception('"' . $date . '" could not be parsed by \DateTime constructor: ' . $exception->getMessage(), 1241722579);
            }
        }