fix: ics27 check packet data length explicitly over nil check (#1882)

* using len check in favour of nil check for interchain account packet data

* adding changelog

* updating changelog

(cherry picked from commit 73fdde9)

CHANGELOG.md

@@ -45,6 +45,8 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 ### State Machine Breaking
 
+* (apps/27-interchain-accounts) [\#1882](https://github.com/cosmos/ibc-go/pull/1882) Explicitly check length of interchain account packet data in favour of nil check.
+
 ### Improvements
 
 * (core/02-client) [\#1570](https://github.com/cosmos/ibc-go/pull/1570) Emitting an event when handling an upgrade client proposal.

modules/apps/27-interchain-accounts/types/packet.go

@@ -16,7 +16,7 @@ func (iapd InterchainAccountPacketData) ValidateBasic() error {
 		return sdkerrors.Wrap(ErrInvalidOutgoingData, "packet data type cannot be unspecified")
 	}
 
-	if iapd.Data == nil {
+	if len(iapd.Data) == 0 {
 		return sdkerrors.Wrap(ErrInvalidOutgoingData, "packet data cannot be empty")
 	}
 

modules/apps/27-interchain-accounts/types/packet_test.go

@@ -40,6 +40,15 @@ func (suite *TypesTestSuite) TestValidateBasic() {
 		},
 		{
 			"empty data",
+			types.InterchainAccountPacketData{
+				Type: types.EXECUTE_TX,
+				Data: []byte{},
+				Memo: "memo",
+			},
+			false,
+		},
+		{
+			"nil data",
 			types.InterchainAccountPacketData{
 				Type: types.EXECUTE_TX,
 				Data: nil,