imp!: removed 'ConsensusHost' interface

CHANGELOG.md

@@ -76,6 +76,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 * (light-clients/06-solomachine) [\#6888](https://github.com/cosmos/ibc-go/pull/6888) Remove `TypeClientMisbehaviour` constant and the `Type` method on `Misbehaviour`.
 * (light-clients/06-solomachine, light-clients/07-tendermint) [\#6891](https://github.com/cosmos/ibc-go/pull/6891) The `VerifyMembership` and `VerifyNonMembership` functions of solomachine's `ClientState` have been made private. The `VerifyMembership`, `VerifyNonMembership`, `GetTimestampAtHeight`, `Status` and `Initialize` functions of tendermint's `ClientState` have been made private.
 * (core/04-channel) [\#6902](https://github.com/cosmos/ibc-go/pull/6902) Add channel version to core application callbacks.
+* (core/03-connection, core/02-client) [\#6937](https://github.com/cosmos/ibc-go/pull/6937) Remove 'ConsensusHost' interface, also removing self client and consensus state validation.
 
 ### State Machine Breaking
 

docs/docs/01-ibc/02-integration.md

@@ -98,7 +98,6 @@ func NewApp(...args) *App {
     appCodec,
     keys[ibcexported.StoreKey],
     app.GetSubspace(ibcexported.ModuleName),
-    ibctm.NewConsensusHost(app.StakingKeeper),
     app.UpgradeKeeper,
     scopedIBCKeeper,
     authtypes.NewModuleAddress(govtypes.ModuleName).String(),

docs/docs/05-migrations/13-v8-to-v9.md

@@ -17,6 +17,7 @@ There are four sections based on the four potential user groups of this document
         - [API removals](#api-removals)
         - [02-client](#02-client)
         - [03-connection](#03-connection)
+            - [Removal of self client and consensus state from connection handshake](#removal-of-self-client-and-consensus-state-from-connection-handshake)
         - [04-channel](#04-channel)
         - [05-port](#05-port)
         - [23-commitment](#23-commitment)
@@ -55,26 +56,78 @@ govRouter.AddRoute(govtypes.RouterKey, govv1beta1.ProposalHandler).
 
 ## IBC core
 
+- Because the self client and consensus state validation has been removed from the connection handshake (see section [Removal of self client and consensus state from connection handshake](#removal-of-self-client-and-consensus-state-from-connection-handshake) for more details), the IBC core keeper does not need the staking keeper anymore to introspects the (self) past historical info at a given height and construct the expected consensus state at that height. Thus, the signature of IBC core keeper constructor function `NewKeeper` has been updated:
+
+```diff
+func NewKeeper(
+  cdc codec.BinaryCodec, key storetypes.StoreKey, paramSpace types.ParamSubspace,
+- stakingKeeper clienttypes.StakingKeeper, 
+  upgradeKeeper clienttypes.UpgradeKeeper,
+  scopedKeeper capabilitykeeper.ScopedKeeper, authority string,
+) *Keeper 
+```
+
 ### API removals
 
 - The [`exported.ChannelI`](https://github.com/cosmos/ibc-go/blob/v8.0.0/modules/core/exported/channel.go#L3-L11) and [`exported.CounterpartyChannelI`](https://github.com/cosmos/ibc-go/blob/v8.0.0/modules/core/exported/channel.go#L13-L19) interfaces have been removed. Please use the concrete types.
 - The [`exported.ConnectionI`](https://github.com/cosmos/ibc-go/blob/v8.0.0/modules/core/exported/connection.go#L6-L13) and [`exported.CounterpartyConnectionI`](https://github.com/cosmos/ibc-go/blob/v8.0.0/modules/core/exported/connection.go#L15-L21) interfaces have been removed. Please use the concrete types.
 - The [`Router` reference](https://github.com/cosmos/ibc-go/blob/v8.0.0/modules/core/keeper/keeper.go#L35) has been removed from the IBC core keeper in [#6138](https://github.com/cosmos/ibc-go/pull/6138). Please use `PortKeeper.Router` instead. 
 - The [composite interface `QueryServer`](https://github.com/cosmos/ibc-go/blob/v8.0.0/modules/core/types/query.go#L14-L19) has been removed from package `core/types`. Please use the granular `QueryServer` interfaces for IBC submodules directly.
 - The [`TypeClientMisbehaviour` constant](https://github.com/cosmos/ibc-go/blob/v8.0.0/modules/core/exported/client.go#L17) has been removed.
+- The function [`SetConsensusHost`](https://github.com/cosmos/ibc-go/blob/v8.3.0/modules/core/keeper/keeper.go#L88-L96) has been removed because the self client and consensus state validation has been removed from the connection handshake. See section [Removal of self client and consensus state from connection handshake](#removal-of-self-client-and-consensus-state-from-connection-handshake) for more details.
 
 ### 02-client
 
 - The `QueryVerifyMembershipRequest` protobuf message has been modified to include `commitment.v2.MerklePath`. The deprecated `commitment.v1.MerklePath` field has been `reserved`. [See 23-commitment](#23-commitment).
 - The function [`CreateLocalhostClient`](https://github.com/cosmos/ibc-go/blob/v8.0.0/modules/core/02-client/keeper/keeper.go#L56) has been removed. The localhost client is now stateless.
 - The function [`NewClientProposalHandler`](https://github.com/cosmos/ibc-go/blob/v8.0.0/modules/core/02-client/proposal_handler.go#L18) has been removed in [#6777](https://github.com/cosmos/ibc-go/pull/6777).
 - The deprecated [`ClientUpdateProposal` and `UpgradeProposal` messages](https://github.com/cosmos/ibc-go/blob/v8.0.0/proto/ibc/core/client/v1/client.proto#L67-L113) have been removed in [\#6782](https://github.com/cosmos/ibc-go/pull/6782). Please use [`MsgRecoverClient`](https://github.com/cosmos/ibc-go/blob/release/v9.0.x/proto/ibc/core/client/v1/tx.proto#L125-L138) and [`MsgIBCSoftwareUpgrade`](https://github.com/cosmos/ibc-go/blob/release/v9.0.x/proto/ibc/core/client/v1/tx.proto#L143-L158) respectively instead.
+- Because the self client and consensus state validation has been removed from the connection handshake (see section [Removal of self client and consensus state from connection handshake](#removal-of-self-client-and-consensus-state-from-connection-handshake) for more details):
+    - The [ConsensusHost interface](https://github.com/cosmos/ibc-go/blob/v8.3.0/modules/core/02-client/types/client.go#L25-L29) has been removed.
+    - The function [`SetConsensusHost`](https://github.com/cosmos/ibc-go/blob/v8.3.0/modules/core/02-client/keeper/keeper.go#L61-L68) has been removed.
+    - The functions [`GetSelfConsensusState` and `ValidateSelfClient`](https://github.com/cosmos/ibc-go/blob/v8.3.0/modules/core/02-client/keeper/keeper.go#L256-L269) have been removed.
 
 ### 03-connection
 
 - The [functions `GetState()`, `GetClientID()`, `GetCounterparty()`, `GetVersions()`, and `GetDelayPeriod()`](https://github.com/cosmos/ibc-go/blob/v8.0.0/modules/core/03-connection/types/connection.go#L25-L48) of the `Connection` type have been removed.
 - The [functions `GetClientID()`, `GetConnectionID()`, and `GetPrefix()`](https://github.com/cosmos/ibc-go/blob/v8.0.0/modules/core/03-connection/types/connection.go#L79-L92) of the `Counterparty` type have been removed.
 
+#### Removal of self client and consensus state from connection handshake
+
+The `ConnectionOpenTry` and `ConnectionOpenAck` handlers no longer validate that the light client on counterparty chain has a valid representation of the executing chain's consensus protocol (please see [#1128](https://github.com/cosmos/ibc/pull/1128) in cosmos/ibc repository for an exhaustive explanation of the reasoning). 
+
+- The fields `client_state`, `proof_client`, `proof_consensus`, `consensus_height` and `host_consensus_state_proof` of `MsgConnectionOpenTry` and `MsgConnectionOpenAck` have been deprecated, and the signature of the constructor functions [`NewMsgConnectionOpenTry`](https://github.com/cosmos/ibc-go/blob/release/v9.0.x/modules/core/03-connection/types/msgs.go#L78) and [`NewMsgConnectionOpenTry`](https://github.com/cosmos/ibc-go/blob/release/v9.0.x/modules/core/03-connection/types/msgs.go#L165) has been accordingly updated:
+
+```diff
+func NewMsgConnectionOpenTry(
+  clientID, counterpartyConnectionID, counterpartyClientID string,
+- counterpartyClient exported.ClientState,
+  counterpartyPrefix commitmenttypes.MerklePrefix,
+  counterpartyVersions []*Version, delayPeriod uint64,
+  initProof []byte,
+- clientProof []byte,
+- consensusProof []byte,
+  proofHeight lienttypes.Height,
+- consensusHeight clienttypes.Height,
+  signer string,
+) *MsgConnectionOpenTry
+
+func NewMsgConnectionOpenAck(
+  connectionID, counterpartyConnectionID string, 
+- counterpartyClient exported.ClientState,
+  tryProof []byte,
+- clientProof []byte,
+- consensusProof []byte,
+  proofHeight clienttypes.Height,
+- consensusHeight clienttypes.Height,
+  version *Version,
+  signer string,
+) *MsgConnectionOpenAck
+```
+
+- The functions [`VerifyClientState` and `VerifyClientConsensusState`](https://github.com/cosmos/ibc-go/blob/v8.3.0/modules/core/03-connection/keeper/verify.go#L20-L101) have been removed.
+- The function [`UnpackInterfaces`](https://github.com/cosmos/ibc-go/blob/v8.0.0/modules/core/03-connection/types/msgs.go#L166) has been removed.
+
 ### 04-channel
 
 - The utility function [`QueryLatestConsensusState`](https://github.com/cosmos/ibc-go/blob/v8.0.0/modules/core/04-channel/client/utils/utils.go#L130) of the CLI has been removed.
@@ -312,6 +365,19 @@ func AssertEvents(
 clientQueryServer := clientkeeper.NewQueryServer(app.IBCKeeper.ClientKeeper)
 ```
 
+- The signature of the function `QueryConnectionHandshakeProof` has changed, since the validation of self client and consensus state has been remove from the connection handshake: 
+
+```diff
+func (endpoint *Endpoint) QueryConnectionHandshakeProof() (
+- clientState exported.ClientState, clientProof,
+- consensusProof []byte, consensusHeight clienttypes.Height,
+  connectioProof []byte, proofHeight clienttypes.Height,
+)
+```
+
+- The functions [`GenerateClientStateProof` and `GenerateConsensusStateProof`](https://github.com/cosmos/ibc-go/blob/v8.0.0/testing/solomachine.go#L513-L547)
+have been removed.
+
 ### API deprecation notice
 
 - The testing package functions `Setup`, `SetupClients`, `SetupConnections`, `CreateConnections`, and `CreateChannels` of the `Coordinator` type have been deprecated and will be removed in v10. Please use the new functions `Setup`, `SetupClients`, `SetupConnections`, `CreateConnections`, `CreateChannels` of the `Path` type.

modules/apps/callbacks/testing/simapp/app.go

@@ -405,7 +405,7 @@ func NewSimApp(
 	app.UpgradeKeeper = upgradekeeper.NewKeeper(skipUpgradeHeights, runtime.NewKVStoreService(keys[upgradetypes.StoreKey]), appCodec, homePath, app.BaseApp, authtypes.NewModuleAddress(govtypes.ModuleName).String())
 
 	app.IBCKeeper = ibckeeper.NewKeeper(
-		appCodec, keys[ibcexported.StoreKey], app.GetSubspace(ibcexported.ModuleName), ibctm.NewConsensusHost(app.StakingKeeper), app.UpgradeKeeper, scopedIBCKeeper, authtypes.NewModuleAddress(govtypes.ModuleName).String(),
+		appCodec, keys[ibcexported.StoreKey], app.GetSubspace(ibcexported.ModuleName), app.UpgradeKeeper, scopedIBCKeeper, authtypes.NewModuleAddress(govtypes.ModuleName).String(),
 	)
 
 	// NOTE: The mock ContractKeeper is only created for testing.

modules/core/02-client/keeper/keeper.go

@@ -27,13 +27,12 @@ type Keeper struct {
 	storeKey       storetypes.StoreKey
 	cdc            codec.BinaryCodec
 	router         *types.Router
-	consensusHost  types.ConsensusHost
 	legacySubspace types.ParamSubspace
 	upgradeKeeper  types.UpgradeKeeper
 }
 
 // NewKeeper creates a new NewKeeper instance
-func NewKeeper(cdc codec.BinaryCodec, key storetypes.StoreKey, legacySubspace types.ParamSubspace, consensusHost types.ConsensusHost, uk types.UpgradeKeeper) *Keeper {
+func NewKeeper(cdc codec.BinaryCodec, key storetypes.StoreKey, legacySubspace types.ParamSubspace, uk types.UpgradeKeeper) *Keeper {
 	router := types.NewRouter()
 	localhostModule := localhost.NewLightClientModule(cdc, key)
 	router.AddRoute(exported.Localhost, localhostModule)
@@ -42,7 +41,6 @@ func NewKeeper(cdc codec.BinaryCodec, key storetypes.StoreKey, legacySubspace ty
 		storeKey:       key,
 		cdc:            cdc,
 		router:         router,
-		consensusHost:  consensusHost,
 		legacySubspace: legacySubspace,
 		upgradeKeeper:  uk,
 	}
@@ -90,15 +88,6 @@ func (k *Keeper) Route(ctx sdk.Context, clientID string) (exported.LightClientMo
 	return clientModule, nil
 }
 
-// SetConsensusHost sets a custom ConsensusHost for self client state and consensus state validation.
-func (k *Keeper) SetConsensusHost(consensusHost types.ConsensusHost) {
-	if consensusHost == nil {
-		panic(errors.New("cannot set a nil self consensus host"))
-	}
-
-	k.consensusHost = consensusHost
-}
-
 // GenerateClientIdentifier returns the next client identifier.
 func (k *Keeper) GenerateClientIdentifier(ctx sdk.Context, clientType string) string {
 	nextClientSeq := k.GetNextClientSequence(ctx)
@@ -315,21 +304,6 @@ func (k *Keeper) GetLatestClientConsensusState(ctx sdk.Context, clientID string)
 	return k.GetClientConsensusState(ctx, clientID, clientModule.LatestHeight(ctx, clientID))
 }
 
-// GetSelfConsensusState introspects the (self) past historical info at a given height
-// and returns the expected consensus state at that height.
-// For now, can only retrieve self consensus states for the current revision
-func (k *Keeper) GetSelfConsensusState(ctx sdk.Context, height exported.Height) (exported.ConsensusState, error) {
-	return k.consensusHost.GetSelfConsensusState(ctx, height)
-}
-
-// ValidateSelfClient validates the client parameters for a client of the running chain.
-// This function is only used to validate the client state the counterparty stores for this chain.
-// NOTE: If the client type is not of type Tendermint then delegate to a custom client validator function.
-// This allows support for non-Tendermint clients, for example 08-wasm clients.
-func (k *Keeper) ValidateSelfClient(ctx sdk.Context, clientState exported.ClientState) error {
-	return k.consensusHost.ValidateSelfClient(ctx, clientState)
-}
-
 // VerifyMembership retrieves the light client module for the clientID and verifies the proof of the existence of a key-value pair at a specified height.
 func (k *Keeper) VerifyMembership(ctx sdk.Context, clientID string, height exported.Height, delayTimePeriod uint64, delayBlockPeriod uint64, proof []byte, path exported.Path, value []byte) error {
 	clientModule, err := k.Route(ctx, clientID)

modules/core/02-client/types/client.go

@@ -11,7 +11,6 @@ import (
 	errorsmod "cosmossdk.io/errors"
 
 	codectypes "github.com/cosmos/cosmos-sdk/codec/types"
-	sdk "github.com/cosmos/cosmos-sdk/types"
 
 	host "github.com/cosmos/ibc-go/v9/modules/core/24-host"
 	"github.com/cosmos/ibc-go/v9/modules/core/exported"
@@ -22,12 +21,6 @@ var (
 	_ codectypes.UnpackInterfacesMessage = (*ConsensusStateWithHeight)(nil)
 )
 
-// ConsensusHost defines an interface used to validate an IBC ClientState and ConsensusState against the host chain's underlying consensus parameters.
-type ConsensusHost interface {
-	GetSelfConsensusState(ctx sdk.Context, height exported.Height) (exported.ConsensusState, error)
-	ValidateSelfClient(ctx sdk.Context, clientState exported.ClientState) error
-}
-
 // NewIdentifiedClientState creates a new IdentifiedClientState instance
 func NewIdentifiedClientState(clientID string, clientState exported.ClientState) IdentifiedClientState {
 	msg, ok := clientState.(proto.Message)

modules/core/03-connection/keeper/events_test.go

@@ -48,13 +48,12 @@ func (suite *KeeperTestSuite) TestMsgConnectionOpenTryEvents() {
 
 	suite.Require().NoError(path.EndpointB.UpdateClient())
 
-	counterpartyClient, clientProof, consensusProof, consensusHeight, initProof, proofHeight := path.EndpointB.QueryConnectionHandshakeProof()
+	initProof, proofHeight := path.EndpointB.QueryConnectionHandshakeProof()
 
 	msg := types.NewMsgConnectionOpenTry(
 		path.EndpointB.ClientID, path.EndpointB.Counterparty.ConnectionID, path.EndpointB.Counterparty.ClientID,
-		counterpartyClient, path.EndpointB.Counterparty.Chain.GetPrefix(), []*types.Version{ibctesting.ConnectionVersion}, path.EndpointB.ConnectionConfig.DelayPeriod,
-		initProof, clientProof, consensusProof,
-		proofHeight, consensusHeight,
+		path.EndpointB.Counterparty.Chain.GetPrefix(), []*types.Version{ibctesting.ConnectionVersion},
+		path.EndpointB.ConnectionConfig.DelayPeriod, initProof, proofHeight,
 		path.EndpointB.Chain.SenderAccount.GetAddress().String(),
 	)
 
@@ -88,13 +87,11 @@ func (suite *KeeperTestSuite) TestMsgConnectionOpenAckEvents() {
 
 	suite.Require().NoError(path.EndpointA.UpdateClient())
 
-	counterpartyClient, clientProof, consensusProof, consensusHeight, tryProof, proofHeight := path.EndpointA.QueryConnectionHandshakeProof()
+	tryProof, proofHeight := path.EndpointA.QueryConnectionHandshakeProof()
 
 	msg := types.NewMsgConnectionOpenAck(
-		path.EndpointA.ConnectionID, path.EndpointA.Counterparty.ConnectionID, counterpartyClient,
-		tryProof, clientProof, consensusProof,
-		proofHeight, consensusHeight,
-		ibctesting.ConnectionVersion,
+		path.EndpointA.ConnectionID, path.EndpointA.Counterparty.ConnectionID,
+		tryProof, proofHeight, ibctesting.ConnectionVersion,
 		path.EndpointA.Chain.SenderAccount.GetAddress().String(),
 	)