Modify Connection Open Init to allow a selected version

proto/ibc/connection/connection.proto

@@ -17,7 +17,8 @@ message MsgConnectionOpenInit {
   string       client_id     = 1 [(gogoproto.moretags) = "yaml:\"client_id\""];
   string       connection_id = 2 [(gogoproto.moretags) = "yaml:\"connection_id\""];
   Counterparty counterparty  = 3 [(gogoproto.nullable) = false];
-  string       signer        = 4;
+  string       version       = 4;
+  string       signer        = 5;
 }
 
 // MsgConnectionOpenTry defines a msg sent by a Relayer to try to open a

x/ibc/03-connection/client/cli/tx.go

@@ -16,15 +16,22 @@ import (
 	host "github.com/cosmos/cosmos-sdk/x/ibc/24-host"
 )
 
+const (
+	flagVersionIdentifier = "version-identifier"
+	flagVersionFeatures   = "version-features"
+)
+
 // NewConnectionOpenInitCmd defines the command to initialize a connection on
 // chain A with a given counterparty chain B
 func NewConnectionOpenInitCmd() *cobra.Command {
 	cmd := &cobra.Command{
 		Use:   "open-init [connection-id] [client-id] [counterparty-connection-id] [counterparty-client-id] [path/to/counterparty_prefix.json]",
 		Short: "Initialize connection on chain A",
-		Long:  "Initialize a connection on chain A with a given counterparty chain B",
+		Long: `Initialize a connection on chain A with a given counterparty chain B.
+	- 'version-identifier' flag can be a single pre-selected version identifier to be used in the handshake.
+	- 'version-features' flag can be a list of features separated by commas to accompany the version identifier.`,
 		Example: fmt.Sprintf(
-			"%s tx %s %s open-init [connection-id] [client-id] [counterparty-connection-id] [counterparty-client-id] [path/to/counterparty_prefix.json]",
+			"%s tx %s %s open-init [connection-id] [client-id] [counterparty-connection-id] [counterparty-client-id] [path/to/counterparty_prefix.json] --version-identifier=\"1.0\" --version-features=\"ORDER_UNORDERED\"",
 			version.AppName, host.ModuleName, types.SubModuleName,
 		),
 		Args: cobra.ExactArgs(5),
@@ -45,9 +52,27 @@ func NewConnectionOpenInitCmd() *cobra.Command {
 				return err
 			}
 
+			var encodedVersion string
+			versionIdentifier, _ := cmd.Flags().GetString(flagVersionIdentifier)
+
+			if versionIdentifier != "" {
+				var features []string
+
+				versionFeatures, _ := cmd.Flags().GetString(flagVersionFeatures)
+				if versionFeatures != "" {
+					features = strings.Split(versionFeatures, ",")
+				}
+
+				version := types.NewVersion(versionIdentifier, features)
+				encodedVersion, err = version.Encode()
+				if err != nil {
+					return err
+				}
+			}
+
 			msg := types.NewMsgConnectionOpenInit(
 				connectionID, clientID, counterpartyConnectionID, counterpartyClientID,
-				counterpartyPrefix, clientCtx.GetFromAddress(),
+				counterpartyPrefix, encodedVersion, clientCtx.GetFromAddress(),
 			)
 
 			if err := msg.ValidateBasic(); err != nil {
@@ -58,6 +83,10 @@ func NewConnectionOpenInitCmd() *cobra.Command {
 		},
 	}
 
+	// NOTE: we should use empty default values since the user may not want to select a version
+	// at this step in the handshake.
+	cmd.Flags().String(flagVersionIdentifier, "", "version identifier to be used in the connection handshake version negotiation")
+	cmd.Flags().String(flagVersionFeatures, "", "version features list separated by commas without spaces. The features must function with the version identifier.")
 	flags.AddTxFlagsToCmd(cmd)
 
 	return cmd

x/ibc/03-connection/handler.go

@@ -11,7 +11,7 @@ import (
 // HandleMsgConnectionOpenInit defines the sdk.Handler for MsgConnectionOpenInit
 func HandleMsgConnectionOpenInit(ctx sdk.Context, k keeper.Keeper, msg *types.MsgConnectionOpenInit) (*sdk.Result, error) {
 	if err := k.ConnOpenInit(
-		ctx, msg.ConnectionId, msg.ClientId, msg.Counterparty,
+		ctx, msg.ConnectionId, msg.ClientId, msg.Counterparty, msg.Version,
 	); err != nil {
 		return nil, sdkerrors.Wrap(err, "connection handshake open init failed")
 	}

x/ibc/03-connection/keeper/handshake.go

@@ -21,14 +21,24 @@ func (k Keeper) ConnOpenInit(
 	connectionID, // identifier
 	clientID string,
 	counterparty types.Counterparty, // desiredCounterpartyConnectionIdentifier, counterpartyPrefix, counterpartyClientIdentifier
+	version string,
 ) error {
 	_, found := k.GetConnection(ctx, connectionID)
 	if found {
 		return types.ErrConnectionExists
 	}
 
+	versions := types.GetCompatibleEncodedVersions()
+	if version != "" {
+		if !types.IsSupportedVersion(version) {
+			return sdkerrors.Wrap(types.ErrInvalidVersion, "version is not supported")
+		}
+
+		versions = []string{version}
+	}
+
 	// connection defines chain A's ConnectionEnd
-	connection := types.NewConnectionEnd(types.INIT, clientID, counterparty, types.GetCompatibleEncodedVersions())
+	connection := types.NewConnectionEnd(types.INIT, clientID, counterparty, versions)
 	k.SetConnection(ctx, connectionID, connection)
 
 	if err := k.addConnectionToClient(ctx, clientID, connectionID); err != nil {

x/ibc/03-connection/keeper/handshake_test.go

@@ -17,6 +17,7 @@ func (suite *KeeperTestSuite) TestConnOpenInit() {
 	var (
 		clientA string
 		clientB string
+		version string
 	)
 
 	testCases := []struct {
@@ -27,9 +28,17 @@ func (suite *KeeperTestSuite) TestConnOpenInit() {
 		{"success", func() {
 			clientA, clientB = suite.coordinator.SetupClients(suite.chainA, suite.chainB, ibctesting.Tendermint)
 		}, true},
+		{"success with non empty version", func() {
+			clientA, clientB = suite.coordinator.SetupClients(suite.chainA, suite.chainB, ibctesting.Tendermint)
+			version = types.GetCompatibleEncodedVersions()[0]
+		}, true},
 		{"connection already exists", func() {
 			clientA, clientB, _, _ = suite.coordinator.SetupClientConnections(suite.chainA, suite.chainB, ibctesting.Tendermint)
 		}, false},
+		{"invalid version", func() {
+			clientA, clientB = suite.coordinator.SetupClients(suite.chainA, suite.chainB, ibctesting.Tendermint)
+			version = "bad version"
+		}, false},
 		{"couldn't add connection to client", func() {
 			// swap client identifiers to result in client that does not exist
 			clientB, clientA = suite.coordinator.SetupClients(suite.chainA, suite.chainB, ibctesting.Tendermint)
@@ -40,14 +49,15 @@ func (suite *KeeperTestSuite) TestConnOpenInit() {
 		tc := tc
 		suite.Run(tc.msg, func() {
 			suite.SetupTest() // reset
+			version = ""      // must be explicitly changed
 
 			tc.malleate()
 
 			connA := suite.chainA.GetFirstTestConnection(clientA, clientB)
 			connB := suite.chainB.GetFirstTestConnection(clientB, clientA)
 			counterparty := types.NewCounterparty(clientB, connB.ID, suite.chainB.GetPrefix())
 
-			err := suite.chainA.App.IBCKeeper.ConnectionKeeper.ConnOpenInit(suite.chainA.GetContext(), connA.ID, clientA, counterparty)
+			err := suite.chainA.App.IBCKeeper.ConnectionKeeper.ConnOpenInit(suite.chainA.GetContext(), connA.ID, clientA, counterparty, version)
 
 			if tc.expPass {
 				suite.Require().NoError(err)