imp(ica/host): implemented 'PacketDataUnmarshaler' (cosmos#4587)

* imp: added PacketDataUnmarshaler to ica/host

* style: ran gofumpt

---------

Co-authored-by: colin axnér <25233464+colin-axner@users.noreply.github.com>

modules/apps/27-interchain-accounts/host/ibc_module.go

@@ -12,10 +12,16 @@ import (
 	"github.com/cosmos/ibc-go/v8/modules/apps/27-interchain-accounts/host/types"
 	icatypes "github.com/cosmos/ibc-go/v8/modules/apps/27-interchain-accounts/types"
 	channeltypes "github.com/cosmos/ibc-go/v8/modules/core/04-channel/types"
+	porttypes "github.com/cosmos/ibc-go/v8/modules/core/05-port/types"
 	ibcerrors "github.com/cosmos/ibc-go/v8/modules/core/errors"
 	ibcexported "github.com/cosmos/ibc-go/v8/modules/core/exported"
 )
 
+var (
+	_ porttypes.IBCModule             = (*IBCModule)(nil)
+	_ porttypes.PacketDataUnmarshaler = (*IBCModule)(nil)
+)
+
 // IBCModule implements the ICS26 interface for interchain accounts host chains
 type IBCModule struct {
 	keeper keeper.Keeper
@@ -149,3 +155,15 @@ func (IBCModule) OnTimeoutPacket(
 ) error {
 	return errorsmod.Wrap(icatypes.ErrInvalidChannelFlow, "cannot cause a packet timeout on a host channel end, a host chain does not send a packet over the channel")
 }
+
+// UnmarshalPacketData attempts to unmarshal the provided packet data bytes
+// into an InterchainAccountPacketData. This function implements the optional
+// PacketDataUnmarshaler interface required for ADR 008 support.
+func (IBCModule) UnmarshalPacketData(bz []byte) (interface{}, error) {
+	var data icatypes.InterchainAccountPacketData
+	err := data.UnmarshalJSON(bz)
+	if err != nil {
+		return nil, err
+	}
+	return data, nil
+}

modules/apps/27-interchain-accounts/host/ibc_module_test.go

@@ -14,6 +14,7 @@ import (
 	banktypes "github.com/cosmos/cosmos-sdk/x/bank/types"
 
 	capabilitytypes "github.com/cosmos/ibc-go/modules/capability/types"
+	icahost "github.com/cosmos/ibc-go/v8/modules/apps/27-interchain-accounts/host"
 	"github.com/cosmos/ibc-go/v8/modules/apps/27-interchain-accounts/host/types"
 	icatypes "github.com/cosmos/ibc-go/v8/modules/apps/27-interchain-accounts/types"
 	feetypes "github.com/cosmos/ibc-go/v8/modules/apps/29-fee/types"
@@ -714,3 +715,26 @@ func (suite *InterchainAccountsTestSuite) assertBalance(addr sdk.AccAddress, exp
 	balance := suite.chainB.GetSimApp().BankKeeper.GetBalance(suite.chainB.GetContext(), addr, sdk.DefaultBondDenom)
 	suite.Require().Equal(expBalance[0], balance)
 }
+
+func (suite *InterchainAccountsTestSuite) TestPacketDataUnmarshalerInterface() {
+	path := NewICAPath(suite.chainA, suite.chainB)
+	suite.coordinator.SetupConnections(path)
+	err := SetupICAPath(path, TestOwnerAddress)
+	suite.Require().NoError(err)
+
+	expPacketData := icatypes.InterchainAccountPacketData{
+		Type: icatypes.EXECUTE_TX,
+		Data: []byte("data"),
+		Memo: "",
+	}
+
+	packetData, err := icahost.IBCModule{}.UnmarshalPacketData(expPacketData.GetBytes())
+	suite.Require().NoError(err)
+	suite.Require().Equal(expPacketData, packetData)
+
+	// test invalid packet data
+	invalidPacketData := []byte("invalid packet data")
+	packetData, err = icahost.IBCModule{}.UnmarshalPacketData(invalidPacketData)
+	suite.Require().Error(err)
+	suite.Require().Nil(packetData)
+}