In savePaymentGatewayResponse method of PaymentGatewayServices class, we are
setting the "gatewayMessage" field on the GenericValue of
PaymentGatewayRespMsg, but there is no field named "gatewayMessage" in
entity PaymentGatewayRespMsg but instead we need to use "pgrMessage" in
place of "gatewayMessage".
I guess we mistakely assumed the GenericValue which we get from the context,
context.get("paymentGatewayResponse");, to be of PaymentGatewayResponse, but
its the GenericValue of PaymentGatewayRespMsg but while putting it on the
context we named it as "paymentGatewayResponse".
I have changed the savePaymentGatewayResponse, and will submit the patch,
but before submitting I would like to confirm this.
