chore: adding UpdateStateOnMisbehaviour to 07-tendermint (cosmos#1168)

* adding UpdateStateOnMisbehaviour with basic test

* removing redundant return values

* removing unnecessary CommitBlock in test func

* Update modules/light-clients/07-tendermint/types/update.go

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

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

modules/light-clients/07-tendermint/types/update.go

@@ -13,6 +13,7 @@ import (
 
 	clienttypes "github.com/cosmos/ibc-go/v3/modules/core/02-client/types"
 	commitmenttypes "github.com/cosmos/ibc-go/v3/modules/core/23-commitment/types"
+	host "github.com/cosmos/ibc-go/v3/modules/core/24-host"
 	"github.com/cosmos/ibc-go/v3/modules/core/exported"
 )
 
@@ -283,3 +284,11 @@ func (cs ClientState) pruneOldestConsensusState(ctx sdk.Context, cdc codec.Binar
 		deleteConsensusMetadata(clientStore, pruneHeight)
 	}
 }
+
+// UpdateStateOnMisbehaviour updates state upon misbehaviour, freezing the ClientState. This method should only be called when misbehaviour is detected
+// as it does not perform any misbehaviour checks.
+func (cs ClientState) UpdateStateOnMisbehaviour(ctx sdk.Context, cdc codec.BinaryCodec, clientStore sdk.KVStore) {
+	cs.FrozenHeight = FrozenHeight
+
+	clientStore.Set(host.ClientStateKey(), clienttypes.MustMarshalClientState(cdc, &cs))
+}

modules/light-clients/07-tendermint/upgrade_test.go

@@ -5,6 +5,7 @@ import (
 
 	clienttypes "github.com/cosmos/ibc-go/v3/modules/core/02-client/types"
 	commitmenttypes "github.com/cosmos/ibc-go/v3/modules/core/23-commitment/types"
+	host "github.com/cosmos/ibc-go/v3/modules/core/24-host"
 	"github.com/cosmos/ibc-go/v3/modules/core/exported"
 	"github.com/cosmos/ibc-go/v3/modules/light-clients/07-tendermint/types"
 	ibctesting "github.com/cosmos/ibc-go/v3/testing"
@@ -481,3 +482,53 @@ func (suite *TendermintTestSuite) TestVerifyUpgrade() {
 		}
 	}
 }
+
+func (suite *TendermintTestSuite) TestUpdateStateOnMisbehaviour() {
+	var (
+		path *ibctesting.Path
+	)
+
+	testCases := []struct {
+		name     string
+		malleate func()
+		expPass  bool
+	}{
+		{
+			"success",
+			func() {},
+			true,
+		},
+	}
+
+	for _, tc := range testCases {
+		tc := tc
+
+		suite.Run(tc.name, func() {
+			// reset suite to create fresh application state
+			suite.SetupTest()
+			path = ibctesting.NewPath(suite.chainA, suite.chainB)
+
+			err := path.EndpointA.CreateClient()
+			suite.Require().NoError(err)
+
+			tc.malleate()
+
+			clientState := path.EndpointA.GetClientState()
+			clientStore := suite.chainA.App.GetIBCKeeper().ClientKeeper.ClientStore(suite.chainA.GetContext(), path.EndpointA.ClientID)
+
+			// TODO: remove casting when 'UpdateState' is an interface function.
+			tmClientState, ok := clientState.(*types.ClientState)
+			suite.Require().True(ok)
+
+			tmClientState.UpdateStateOnMisbehaviour(suite.chainA.GetContext(), suite.chainA.App.AppCodec(), clientStore)
+
+			if tc.expPass {
+				clientStateBz := clientStore.Get(host.ClientStateKey())
+				suite.Require().NotEmpty(clientStateBz)
+
+				newClientState := clienttypes.MustUnmarshalClientState(suite.chainA.Codec, clientStateBz)
+				suite.Require().Equal(frozenHeight, newClientState.(*types.ClientState).FrozenHeight)
+			}
+		})
+	}
+}