Array to string conversion

[enumag]

Q	A
Bug report?	yes
Feature request?	no
BC Break report?	no
RFC?	no

Recently I found an array to string conversion bug in mhujer/jms-serializer-uuid#14 (fixed here). While investigating the author found out that the same issue exists in serializer itself for DateTimes. We can't assume that $data can be safely converted to string here:

serializer/src/Handler/DateHandler.php

Lines 232 to 261 in e4b516e

	private function parseDateTime($data, array $type, bool $immutable = false): \DateTimeInterface
	{
	$timezone = !empty($type['params'][1]) ? new \DateTimeZone($type['params'][1]) : $this->defaultTimezone;
	$formats = $this->getDeserializationFormats($type);
	$formatTried = [];
	foreach ($formats as $format) {
	if ($immutable) {
	$datetime = \DateTimeImmutable::createFromFormat($format, (string) $data, $timezone);
	} else {
	$datetime = \DateTime::createFromFormat($format, (string) $data, $timezone);
	}
	if (false !== $datetime) {
	if ('U' === $format) {
	$datetime = $datetime->setTimezone($timezone);
	}
	return $datetime;
	}
	$formatTried[] = $format;
	}
	throw new RuntimeException(sprintf(
	'Invalid datetime "%s", expected one of the format %s.',
	$data,
	'"' . implode('", "', $formatTried) . '"'
	));
	}

Other handlers might suffer from this too.

Steps required to reproduce the problem

Send an array value where API expects a DateTime string.

Expected Result

Error that the value is invalid.

Actual Result

Array to string conversion warning.