fix: assert previous channel identifer is empty in Msg ValidateBasic …

…(backport cosmos#1792) (cosmos#1827)

* fix: assert previous channel identifer is empty in Msg ValidateBasic (cosmos#1792)

* remove previous channel id from NewMsgChanOpenTry, assert previous channel id to be empty

* add changelog entry

* move changelog entry to correct location

* add migration docs

* Update docs/migrations/v3-to-v4.md

Co-authored-by: Carlos Rodriguez <carlos@interchain.io>

* Update CHANGELOG.md

Co-authored-by: Carlos Rodriguez <carlos@interchain.io>

Co-authored-by: Carlos Rodriguez <carlos@interchain.io>
(cherry picked from commit 4a781e5)

# Conflicts:
#	CHANGELOG.md

* fix conflicts

Co-authored-by: colin axnér <25233464+colin-axner@users.noreply.github.com>
Co-authored-by: Carlos Rodriguez <carlos@interchain.io>

CHANGELOG.md

@@ -43,6 +43,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 ### API Breaking
 
+* (core/04-channel) [\#1792](https://github.com/cosmos/ibc-go/pull/1792) Remove `PreviousChannelID` from `NewMsgChannelOpenTry` arguments. `MsgChannelOpenTry.ValidateBasic()` returns error if the deprecated `PreviousChannelID` is not empty. 
 * (modules/core/03-connection) [\#1672](https://github.com/cosmos/ibc-go/pull/1672) Remove crossing hellos from connection handshakes. The `PreviousConnectionId` in `MsgConnectionOpenTry` has been deprecated.
 * (modules/core/04-channel) [\#1317](https://github.com/cosmos/ibc-go/pull/1317) Remove crossing hellos from channel handshakes. The `PreviousChannelId` in `MsgChannelOpenTry` has been deprecated.  
 * (transfer) [\#1250](https://github.com/cosmos/ibc-go/pull/1250) Deprecate `GetTransferAccount` since the `transfer` module account is never used.

docs/migrations/v3-to-v4.md

@@ -63,6 +63,8 @@ Crossing hellos have been removed from 04-channel handshake negotiation.
 IBC Applications no longer need to account from already claimed capabilities in the `OnChanOpenTry` callback. The capability provided by core IBC must be able to be claimed with error. 
 `PreviousChannelId` in `MsgChannelOpenTry` has been deprecated and is no longer used by core IBC.
 
+`NewMsgChannelOpenTry` no longer takes in the `PreviousChannelId` as crossing hellos are no longer supported. A non-empty `PreviousChannelId` will fail basic validation for this message. 
+
 ### ICS27 - Interchain Accounts
 
 The `RegisterInterchainAccount` API has been modified to include an additional `version` argument. This change has been made in order to support ICS29 fee middleware, for relayer incentivization of ICS27 packets.

modules/apps/27-interchain-accounts/controller/ibc_middleware_test.go

@@ -244,7 +244,7 @@ func (suite *InterchainAccountsTestSuite) TestChanOpenTry() {
 	proofInit, proofHeight := path.EndpointB.Chain.QueryProof(channelKey)
 
 	// use chainA (controller) for ChanOpenTry
-	msg := channeltypes.NewMsgChannelOpenTry(path.EndpointA.ChannelConfig.PortID, path.EndpointA.ChannelID, TestVersion, channeltypes.ORDERED, []string{path.EndpointA.ConnectionID}, path.EndpointB.ChannelConfig.PortID, path.EndpointB.ChannelID, TestVersion, proofInit, proofHeight, icatypes.ModuleName)
+	msg := channeltypes.NewMsgChannelOpenTry(path.EndpointA.ChannelConfig.PortID, TestVersion, channeltypes.ORDERED, []string{path.EndpointA.ConnectionID}, path.EndpointB.ChannelConfig.PortID, path.EndpointB.ChannelID, TestVersion, proofInit, proofHeight, icatypes.ModuleName)
 	handler := suite.chainA.GetSimApp().MsgServiceRouter().Handler(msg)
 	_, err = handler(suite.chainA.GetContext(), msg)
 

modules/core/04-channel/types/msgs.go

@@ -66,15 +66,14 @@ var _ sdk.Msg = &MsgChannelOpenTry{}
 // It is left as an argument for go API backwards compatibility.
 // nolint:interfacer
 func NewMsgChannelOpenTry(
-	portID, previousChannelID, version string, channelOrder Order, connectionHops []string,
+	portID, version string, channelOrder Order, connectionHops []string,
 	counterpartyPortID, counterpartyChannelID, counterpartyVersion string,
 	proofInit []byte, proofHeight clienttypes.Height, signer string,
 ) *MsgChannelOpenTry {
 	counterparty := NewCounterparty(counterpartyPortID, counterpartyChannelID)
 	channel := NewChannel(TRYOPEN, channelOrder, counterparty, connectionHops, version)
 	return &MsgChannelOpenTry{
 		PortId:              portID,
-		PreviousChannelId:   previousChannelID,
 		Channel:             channel,
 		CounterpartyVersion: counterpartyVersion,
 		ProofInit:           proofInit,
@@ -89,9 +88,7 @@ func (msg MsgChannelOpenTry) ValidateBasic() error {
 		return sdkerrors.Wrap(err, "invalid port ID")
 	}
 	if msg.PreviousChannelId != "" {
-		if !IsValidChannelID(msg.PreviousChannelId) {
-			return sdkerrors.Wrap(ErrInvalidChannelIdentifier, "invalid previous channel ID")
-		}
+		return sdkerrors.Wrap(ErrInvalidChannelIdentifier, "previous channel identifier must be empty, this field has been deprecated as crossing hellos are no longer supported")
 	}
 	if len(msg.ProofInit) == 0 {
 		return sdkerrors.Wrap(commitmenttypes.ErrInvalidProof, "cannot submit an empty proof init")

modules/core/04-channel/types/msgs_test.go

@@ -153,25 +153,23 @@ func (suite *TypesTestSuite) TestMsgChannelOpenTryValidateBasic() {
 		msg     *types.MsgChannelOpenTry
 		expPass bool
 	}{
-		{"", types.NewMsgChannelOpenTry(portid, chanid, version, types.ORDERED, connHops, cpportid, cpchanid, version, suite.proof, height, addr), true},
-		{"too short port id", types.NewMsgChannelOpenTry(invalidShortPort, chanid, version, types.ORDERED, connHops, cpportid, cpchanid, version, suite.proof, height, addr), false},
-		{"too long port id", types.NewMsgChannelOpenTry(invalidLongPort, chanid, version, types.ORDERED, connHops, cpportid, cpchanid, version, suite.proof, height, addr), false},
-		{"port id contains non-alpha", types.NewMsgChannelOpenTry(invalidPort, chanid, version, types.ORDERED, connHops, cpportid, cpchanid, version, suite.proof, height, addr), false},
-		{"too short channel id", types.NewMsgChannelOpenTry(portid, invalidShortChannel, version, types.ORDERED, connHops, cpportid, cpchanid, version, suite.proof, height, addr), false},
-		{"too long channel id", types.NewMsgChannelOpenTry(portid, invalidLongChannel, version, types.ORDERED, connHops, cpportid, cpchanid, version, suite.proof, height, addr), false},
-		{"channel id contains non-alpha", types.NewMsgChannelOpenTry(portid, invalidChannel, version, types.ORDERED, connHops, cpportid, cpchanid, version, suite.proof, height, addr), false},
-		{"", types.NewMsgChannelOpenTry(portid, chanid, version, types.ORDERED, connHops, cpportid, cpchanid, "", suite.proof, height, addr), true},
-		{"proof height is zero", types.NewMsgChannelOpenTry(portid, chanid, version, types.ORDERED, connHops, cpportid, cpchanid, version, suite.proof, clienttypes.ZeroHeight(), addr), false},
-		{"invalid channel order", types.NewMsgChannelOpenTry(portid, chanid, version, types.Order(4), connHops, cpportid, cpchanid, version, suite.proof, height, addr), false},
-		{"connection hops more than 1 ", types.NewMsgChannelOpenTry(portid, chanid, version, types.UNORDERED, invalidConnHops, cpportid, cpchanid, version, suite.proof, height, addr), false},
-		{"too short connection id", types.NewMsgChannelOpenTry(portid, chanid, version, types.UNORDERED, invalidShortConnHops, cpportid, cpchanid, version, suite.proof, height, addr), false},
-		{"too long connection id", types.NewMsgChannelOpenTry(portid, chanid, version, types.UNORDERED, invalidLongConnHops, cpportid, cpchanid, version, suite.proof, height, addr), false},
-		{"connection id contains non-alpha", types.NewMsgChannelOpenTry(portid, chanid, version, types.UNORDERED, []string{invalidConnection}, cpportid, cpchanid, version, suite.proof, height, addr), false},
-		{"", types.NewMsgChannelOpenTry(portid, chanid, "", types.UNORDERED, connHops, cpportid, cpchanid, version, suite.proof, height, addr), true},
-		{"invalid counterparty port id", types.NewMsgChannelOpenTry(portid, chanid, version, types.UNORDERED, connHops, invalidPort, cpchanid, version, suite.proof, height, addr), false},
-		{"invalid counterparty channel id", types.NewMsgChannelOpenTry(portid, chanid, version, types.UNORDERED, connHops, cpportid, invalidChannel, version, suite.proof, height, addr), false},
-		{"empty proof", types.NewMsgChannelOpenTry(portid, chanid, version, types.UNORDERED, connHops, cpportid, cpchanid, version, emptyProof, height, addr), false},
-		{"channel not in TRYOPEN state", &types.MsgChannelOpenTry{portid, chanid, initChannel, version, suite.proof, height, addr}, false},
+		{"", types.NewMsgChannelOpenTry(portid, version, types.ORDERED, connHops, cpportid, cpchanid, version, suite.proof, height, addr), true},
+		{"too short port id", types.NewMsgChannelOpenTry(invalidShortPort, version, types.ORDERED, connHops, cpportid, cpchanid, version, suite.proof, height, addr), false},
+		{"too long port id", types.NewMsgChannelOpenTry(invalidLongPort, version, types.ORDERED, connHops, cpportid, cpchanid, version, suite.proof, height, addr), false},
+		{"port id contains non-alpha", types.NewMsgChannelOpenTry(invalidPort, version, types.ORDERED, connHops, cpportid, cpchanid, version, suite.proof, height, addr), false},
+		{"", types.NewMsgChannelOpenTry(portid, version, types.ORDERED, connHops, cpportid, cpchanid, "", suite.proof, height, addr), true},
+		{"proof height is zero", types.NewMsgChannelOpenTry(portid, version, types.ORDERED, connHops, cpportid, cpchanid, version, suite.proof, clienttypes.ZeroHeight(), addr), false},
+		{"invalid channel order", types.NewMsgChannelOpenTry(portid, version, types.Order(4), connHops, cpportid, cpchanid, version, suite.proof, height, addr), false},
+		{"connection hops more than 1 ", types.NewMsgChannelOpenTry(portid, version, types.UNORDERED, invalidConnHops, cpportid, cpchanid, version, suite.proof, height, addr), false},
+		{"too short connection id", types.NewMsgChannelOpenTry(portid, version, types.UNORDERED, invalidShortConnHops, cpportid, cpchanid, version, suite.proof, height, addr), false},
+		{"too long connection id", types.NewMsgChannelOpenTry(portid, version, types.UNORDERED, invalidLongConnHops, cpportid, cpchanid, version, suite.proof, height, addr), false},
+		{"connection id contains non-alpha", types.NewMsgChannelOpenTry(portid, version, types.UNORDERED, []string{invalidConnection}, cpportid, cpchanid, version, suite.proof, height, addr), false},
+		{"", types.NewMsgChannelOpenTry(portid, "", types.UNORDERED, connHops, cpportid, cpchanid, version, suite.proof, height, addr), true},
+		{"invalid counterparty port id", types.NewMsgChannelOpenTry(portid, version, types.UNORDERED, connHops, invalidPort, cpchanid, version, suite.proof, height, addr), false},
+		{"invalid counterparty channel id", types.NewMsgChannelOpenTry(portid, version, types.UNORDERED, connHops, cpportid, invalidChannel, version, suite.proof, height, addr), false},
+		{"empty proof", types.NewMsgChannelOpenTry(portid, version, types.UNORDERED, connHops, cpportid, cpchanid, version, emptyProof, height, addr), false},
+		{"channel not in TRYOPEN state", &types.MsgChannelOpenTry{portid, "", initChannel, version, suite.proof, height, addr}, false},
+		{"previous channel id is not empty", &types.MsgChannelOpenTry{portid, chanid, initChannel, version, suite.proof, height, addr}, false},
 	}
 
 	for _, tc := range testCases {

testing/endpoint.go

@@ -295,7 +295,7 @@ func (endpoint *Endpoint) ChanOpenTry() error {
 	proof, height := endpoint.Counterparty.Chain.QueryProof(channelKey)
 
 	msg := channeltypes.NewMsgChannelOpenTry(
-		endpoint.ChannelConfig.PortID, "", // does not support handshake continuation
+		endpoint.ChannelConfig.PortID,
 		endpoint.ChannelConfig.Version, endpoint.ChannelConfig.Order, []string{endpoint.ConnectionID},
 		endpoint.Counterparty.ChannelConfig.PortID, endpoint.Counterparty.ChannelID, endpoint.Counterparty.ChannelConfig.Version,
 		proof, height,