MsgTransferResponse should include the packet sequence

[colin-axner]

Summary

MsgTransferResponse should include the sequence of the packet the transfer is sent in. The value derived in SendTransfer within relay.go should be returned in the message response. The SendTransfer API will need to be modified.

For Admin Use

• Not duplicate issue
• Appropriate labels applied
• Appropriate contributors tagged/assigned

[colin-axner]

This has addition has been requested from external feedback

[crodriguezvega]

• Add sequence number to MsgTransferResponse in proto/ibc/applications/transfer/v1/tx.proto:

// MsgTransferResponse defines the Msg/Transfer response type.
message MsgTransferResponse {
  // sequence number of the packet the transfer is sent it
  uint64 sequence = 1;
}

• Change signature of SendTransfer function in modules/apps/transfer/keeper/relay.go to :

func (k Keeper) SendTransfer(
	ctx sdk.Context,
	sourcePort,
	sourceChannel string,
	token sdk.Coin,
	sender sdk.AccAddress,
	receiver string,
	timeoutHeight clienttypes.Height,
	timeoutTimestamp uint64,
) (uint64, error) 

• Return 0 in the first return argument for all the error situations inside the SendTransfer function; return the sequence found in the first return statement of the function.

• Retrieve the sequence on the place where SendTransfer is called in modules/apps/transfer/keeper/msg_server.go and include it in the MsgTransferResponse:

sequence, err := k.SendTransfer(
  ctx, msg.SourcePort, msg.SourceChannel, msg.Token, sender, msg.Receiver, msg.TimeoutHeight, msg.TimeoutTimestamp,
)
if err != nil {
  return nil, err
}

...

return &types.MsgTransferResponse{sequence}, nil