Allow empty version strings (#6909)

* Allow empty version strings (left over from PR #6904)

* Update spec

Co-authored-by: Christopher Goes <cwgoes@pluranimity.org>

x/ibc/04-channel/types/msgs.go

@@ -2,7 +2,6 @@ package types
 
 import (
 	"encoding/base64"
-	"strings"
 
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
@@ -98,9 +97,6 @@ func (msg MsgChannelOpenTry) ValidateBasic() error {
 	if err := host.ChannelIdentifierValidator(msg.ChannelID); err != nil {
 		return sdkerrors.Wrap(err, "invalid channel ID")
 	}
-	if strings.TrimSpace(msg.CounterpartyVersion) == "" {
-		return sdkerrors.Wrap(ErrInvalidCounterparty, "counterparty version cannot be blank")
-	}
 	if len(msg.ProofInit) == 0 {
 		return sdkerrors.Wrap(commitmenttypes.ErrInvalidProof, "cannot submit an empty proof init")
 	}
@@ -156,9 +152,6 @@ func (msg MsgChannelOpenAck) ValidateBasic() error {
 	if err := host.ChannelIdentifierValidator(msg.ChannelID); err != nil {
 		return sdkerrors.Wrap(err, "invalid channel ID")
 	}
-	if strings.TrimSpace(msg.CounterpartyVersion) == "" {
-		return sdkerrors.Wrap(ErrInvalidCounterparty, "counterparty version cannot be blank")
-	}
 	if len(msg.ProofTry) == 0 {
 		return sdkerrors.Wrap(commitmenttypes.ErrInvalidProof, "cannot submit an empty proof try")
 	}

x/ibc/04-channel/types/msgs_test.go

@@ -188,14 +188,14 @@ func (suite *MsgTestSuite) TestMsgChannelOpenTry() {
 		{testMsgs[4], false, "too short channel id"},
 		{testMsgs[5], false, "too long channel id"},
 		{testMsgs[6], false, "channel id contains non-alpha"},
-		{testMsgs[7], false, "empty counterparty version"},
+		{testMsgs[7], true, ""},
 		{testMsgs[8], false, "proof height is zero"},
 		{testMsgs[9], false, "invalid channel order"},
 		{testMsgs[10], false, "connection hops more than 1 "},
 		{testMsgs[11], false, "too short connection id"},
 		{testMsgs[12], false, "too long connection id"},
 		{testMsgs[13], false, "connection id contains non-alpha"},
-		{testMsgs[14], true, "empty channel version"},
+		{testMsgs[14], true, ""},
 		{testMsgs[15], false, "invalid counterparty port id"},
 		{testMsgs[16], false, "invalid counterparty channel id"},
 		{testMsgs[17], false, "empty proof"},
@@ -238,7 +238,7 @@ func (suite *MsgTestSuite) TestMsgChannelOpenAck() {
 		{testMsgs[4], false, "too short channel id"},
 		{testMsgs[5], false, "too long channel id"},
 		{testMsgs[6], false, "channel id contains non-alpha"},
-		{testMsgs[7], false, "empty counterparty version"},
+		{testMsgs[7], true, ""},
 		{testMsgs[8], false, "empty proof"},
 		{testMsgs[9], false, "proof height is zero"},
 	}

x/ibc/spec/01_concepts.md

@@ -34,7 +34,7 @@ A valid connection version is considered to be in the following format:
 - the version tuple must be enclosed in parentheses
 - the feature set must be enclosed in brackets
 - there should be no space between the comma separting the identifier and the
-feature set
+  feature set
 - the version identifier must no contain any commas
 - each feature must not contain any commas
 - each feature must be separated by commas
@@ -68,6 +68,9 @@ the version proposed by party B using the `MsgChanOpenAck` `CounterpartyVersion`
 field. The application module should throw an error if the version string is
 not valid.
 
+In general empty version strings are to be considered valid options for an 
+application module.
+
 Application modules may implement their own versioning system, such as semantic
 versioning, or they may lean upon the versioning system used for in connection
 version negotiation. To use the connection version semantics the application