json_unpack bug (jansson 2.13.1)

[xback]

When an optional string is not found, all optional strings behind it are skipped

JSON provided in json_t* A:

{
                               "azimuth": null,
                               "latitude": "51.36028611",
                               "longitude": "4.27114444",
                               "height": null,
                               "Managable": null,
                               "SIM_ICCID": null,
                               "SIM_MTN": null,
                               "TruckLicensePlate": null,
                               "TruckSerialNumber": null,
                               "monitoring_environment": "Industry",
                               "monitoring_job_override": null,
                               "node_id": null,
                               "sla": "Gold"
}

C reproducer:

void test(json_t* A)
{
	const char* str_azi = NULL;
	const char* str_lat = NULL;
	const char* str_lon = NULL;
	const char* str_alt = NULL;

//Optionally extract values which are present

// All fail (pointers remain empty)
	json_unpack(A, "{s?s, s?s, s?s, s?s}", \
			"azimuth",   &str_azi, \
			"latitude",  &str_lat, \
			"longitude", &str_lon, \
			"height",    &str_alt);

// Works (latitude and longitude are both extracted as expected)
	json_unpack(A, "{s?s, s?s, s?s, s?s}", \
			"latitude",  &str_lat, \
			"longitude", &str_lon, \
			"azimuth",   &str_azi, \
			"height",    &str_alt);
}