chore: add GetTimestampAtHeight to client state #888 (#1659)

Co-authored-by: Bo Du <bo@polymerlabs.org>

CHANGELOG.md

@@ -121,6 +121,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 ### Improvements
 
+* (client) [\#888](https://github.com/cosmos/ibc-go/pull/888) Add `GetTimestampAtHeight` to `ClientState`
 * (interchain-accounts) [\#1037](https://github.com/cosmos/ibc-go/pull/1037) Add a function `InitModule` to the interchain accounts `AppModule`. This function should be called within the upgrade handler when adding the interchain accounts module to a chain. It should be called in place of InitGenesis (set the consensus version in the version map).
 * (testing) [\#1003](https://github.com/cosmos/ibc-go/pull/1003) Testing chain's `Signer` fields has changed from `[]tmtypes.PrivValidator` to `map[string]tmtypes.PrivValidator` to accomodate valset updates changing the order of the ValidatorSet.
 * (testing) [\#1003](https://github.com/cosmos/ibc-go/pull/1003) `SignAndDeliver` will now just deliver the transaction without creating and committing a block. Thus, it requires that `BeginBlock` MUST be called before `SignAndDeliver`

modules/core/02-client/legacy/v100/solomachine.go

@@ -211,6 +211,13 @@ func (cs ClientState) VerifyNextSequenceRecv(
 	panic("legacy solo machine is deprecated!")
 }
 
+// GetTimestampAtHeight panics!
+func (cs ClientState) GetTimestampAtHeight(
+	sdk.Context, sdk.KVStore, codec.BinaryCodec, exported.Height,
+) (uint64, error) {
+	panic("legacy solo machine is deprecated!")
+}
+
 // VerifyMembership panics!
 func (cs *ClientState) VerifyMembership(
 	ctx sdk.Context,

modules/core/exported/client.go

@@ -214,6 +214,12 @@ type ClientState interface {
 		channelID string,
 		nextSequenceRecv uint64,
 	) error
+	GetTimestampAtHeight(
+		ctx sdk.Context,
+		clientStore sdk.KVStore,
+		cdc codec.BinaryCodec,
+		height Height,
+	) (uint64, error)
 }
 
 // ConsensusState is the state of the consensus process

modules/light-clients/06-solomachine/types/client_state.go

@@ -39,6 +39,19 @@ func (cs ClientState) GetLatestHeight() exported.Height {
 	return clienttypes.NewHeight(0, cs.Sequence)
 }
 
+// GetTimestampAtHeight returns the timestamp in nanoseconds of the consensus state at the given height.
+func (cs ClientState) GetTimestampAtHeight(
+	_ sdk.Context,
+	clientStore sdk.KVStore,
+	cdc codec.BinaryCodec,
+	height exported.Height,
+) (uint64, error) {
+	if !cs.GetLatestHeight().EQ(height) {
+		return 0, sdkerrors.Wrapf(ErrInvalidSequence, "not latest height (%s)", height)
+	}
+	return cs.ConsensusState.Timestamp, nil
+}
+
 // Status returns the status of the solo machine client.
 // The client may be:
 // - Active: if frozen sequence is 0

modules/light-clients/06-solomachine/types/client_state_test.go

@@ -27,7 +27,7 @@ var (
 
 func (suite *SoloMachineTestSuite) TestStatus() {
 	clientState := suite.solomachine.ClientState()
-	// solo machine discards arguements
+	// solo machine discards arguments
 	status := clientState.Status(suite.chainA.GetContext(), nil, nil)
 	suite.Require().Equal(exported.Active, status)
 
@@ -845,3 +845,51 @@ func (suite *SoloMachineTestSuite) TestVerifyNextSeqRecv() {
 		}
 	}
 }
+
+func (suite *SoloMachineTestSuite) TestGetTimestampAtHeight() {
+	tmPath := ibctesting.NewPath(suite.chainA, suite.chainB)
+	suite.coordinator.SetupClients(tmPath)
+	// Single setup for all test cases.
+	suite.SetupTest()
+
+	testCases := []struct {
+		name        string
+		clientState *types.ClientState
+		height      exported.Height
+		expValue    uint64
+		expPass     bool
+	}{
+		{
+			name:        "get timestamp at height exists",
+			clientState: suite.solomachine.ClientState(),
+			height:      suite.solomachine.ClientState().GetLatestHeight(),
+			expValue:    suite.solomachine.ClientState().ConsensusState.Timestamp,
+			expPass:     true,
+		},
+		{
+			name:        "get timestamp at height not exists",
+			clientState: suite.solomachine.ClientState(),
+			height:      suite.solomachine.ClientState().GetLatestHeight().Increment(),
+		},
+	}
+
+	for i, tc := range testCases {
+		tc := tc
+
+		suite.Run(tc.name, func() {
+			ctx := suite.chainA.GetContext()
+
+			ts, err := tc.clientState.GetTimestampAtHeight(
+				ctx, suite.store, suite.chainA.Codec, tc.height,
+			)
+
+			suite.Require().Equal(tc.expValue, ts)
+
+			if tc.expPass {
+				suite.Require().NoError(err, "valid test case %d failed: %s", i, tc.name)
+			} else {
+				suite.Require().Error(err, "invalid test case %d passed: %s", i, tc.name)
+			}
+		})
+	}
+}

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

@@ -58,6 +58,21 @@ func (cs ClientState) GetLatestHeight() exported.Height {
 	return cs.LatestHeight
 }
 
+// GetTimestampAtHeight returns the timestamp in nanoseconds of the consensus state at the given height.
+func (cs ClientState) GetTimestampAtHeight(
+	ctx sdk.Context,
+	clientStore sdk.KVStore,
+	cdc codec.BinaryCodec,
+	height exported.Height,
+) (uint64, error) {
+	// get consensus state at height from clientStore to check for expiry
+	consState, found := GetConsensusState(clientStore, cdc, height)
+	if !found {
+		return 0, sdkerrors.Wrapf(clienttypes.ErrConsensusStateNotFound, "height (%s)", height)
+	}
+	return consState.GetTimestamp(), nil
+}
+
 // Status returns the status of the tendermint client.
 // The client may be:
 // - Active: FrozenHeight is zero and client is not expired

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

@@ -1390,3 +1390,50 @@ func (suite *TendermintTestSuite) TestVerifyNextSeqRecv() {
 		})
 	}
 }
+
+func (suite *TendermintTestSuite) TestGetTimestampAtHeight() {
+	suite.SetupTest()
+
+	path := ibctesting.NewPath(suite.chainA, suite.chainB)
+	path.SetChannelOrdered()
+	suite.coordinator.Setup(path)
+
+	ctx := suite.chainA.GetContext()
+	clientStore := suite.chainA.App.GetIBCKeeper().ClientKeeper.ClientStore(ctx, path.EndpointA.ClientID)
+	clientState := path.EndpointA.GetClientState()
+
+	testCases := []struct {
+		name     string
+		height   exported.Height
+		expValue uint64
+		expPass  bool
+	}{
+		{
+			name:     "get timestamp at height exists",
+			height:   clientState.GetLatestHeight(),
+			expValue: path.EndpointA.GetConsensusState(clientState.GetLatestHeight()).GetTimestamp(),
+			expPass:  true,
+		},
+		{
+			name:   "get timestamp at height not exists",
+			height: clientState.GetLatestHeight().Increment(),
+		},
+	}
+	for _, tc := range testCases {
+		tc := tc
+
+		suite.Run(tc.name, func() {
+			ts, err := clientState.GetTimestampAtHeight(
+				ctx, clientStore, suite.chainA.Codec, tc.height,
+			)
+
+			suite.Require().Equal(tc.expValue, ts)
+
+			if tc.expPass {
+				suite.Require().NoError(err)
+			} else {
+				suite.Require().Error(err)
+			}
+		})
+	}
+}