From dc4d0b768f430e6c07e997b6efc1567c16c46ad8 Mon Sep 17 00:00:00 2001
From: Carlos Rodriguez <carlos@interchain.io>
Date: Fri, 1 Jul 2022 22:45:13 +0200
Subject: [PATCH] delete unused 04-channel version functions (#1636)

* delete unused code and associated tests

* Update CHANGELOG.md

(cherry picked from commit 6c4a44243e6a381293920aab483c44aa840cf556)
---
 CHANGELOG.md                                  |  1 +
 modules/core/04-channel/types/version.go      | 27 -------
 modules/core/04-channel/types/version_test.go | 77 -------------------
 3 files changed, 1 insertion(+), 104 deletions(-)
 delete mode 100644 modules/core/04-channel/types/version.go
 delete mode 100644 modules/core/04-channel/types/version_test.go

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 900ef224f5f..061ebcdb773 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -50,6 +50,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 * (apps/27-interchain-accounts)[\#1565](https://github.com/cosmos/ibc-go/pull/1565) Removing `NewErrorAcknowledgement` in favour of `channeltypes.NewErrorAcknowledgement`.
 * (transfer)[\#1565](https://github.com/cosmos/ibc-go/pull/1565) Removing `NewErrorAcknowledgement` in favour of `channeltypes.NewErrorAcknowledgement`.
 * (channel)[\#1565](https://github.com/cosmos/ibc-go/pull/1565) Updating `NewErrorAcknowledgement` to accept an error instead of a string and removing the possibility of non-deterministic writes to application state.
+* (core/04-channel)[\#1636](https://github.com/cosmos/ibc-go/pull/1636) Removing `SplitChannelVersion` and `MergeChannelVersions` functions since they are not used.
 
 ### State Machine Breaking
 
diff --git a/modules/core/04-channel/types/version.go b/modules/core/04-channel/types/version.go
deleted file mode 100644
index a2696d291ed..00000000000
--- a/modules/core/04-channel/types/version.go
+++ /dev/null
@@ -1,27 +0,0 @@
-package types
-
-import "strings"
-
-const ChannelVersionDelimiter = ":"
-
-// SplitChannelVersion middleware version will split the channel version string
-// into the outermost middleware version and the underlying app version.
-// It will use the default delimiter `:` for middleware versions.
-// In case there's no delimeter, this function returns an empty string for the middleware version (first return argument),
-// and the full input as the second underlying app version.
-func SplitChannelVersion(version string) (middlewareVersion, appVersion string) {
-	// only split out the first middleware version
-	splitVersions := strings.Split(version, ChannelVersionDelimiter)
-	if len(splitVersions) == 1 {
-		return "", version
-	}
-	middlewareVersion = splitVersions[0]
-	appVersion = strings.Join(splitVersions[1:], ChannelVersionDelimiter)
-	return
-}
-
-// MergeChannelVersions merges the provided versions together with the channel version delimiter
-// the versions should be passed in from the highest-level middleware to the base application
-func MergeChannelVersions(versions ...string) string {
-	return strings.Join(versions, ChannelVersionDelimiter)
-}
diff --git a/modules/core/04-channel/types/version_test.go b/modules/core/04-channel/types/version_test.go
deleted file mode 100644
index d735f162ae1..00000000000
--- a/modules/core/04-channel/types/version_test.go
+++ /dev/null
@@ -1,77 +0,0 @@
-package types_test
-
-import (
-	"testing"
-
-	"github.com/stretchr/testify/require"
-
-	"github.com/cosmos/ibc-go/v4/modules/core/04-channel/types"
-)
-
-func TestSplitVersions(t *testing.T) {
-	testCases := []struct {
-		name       string
-		version    string
-		mwVersion  string
-		appVersion string
-	}{
-		{
-			"single wrapped middleware",
-			"fee29-1:ics20-1",
-			"fee29-1",
-			"ics20-1",
-		},
-		{
-			"multiple wrapped middleware",
-			"fee29-1:whitelist:ics20-1",
-			"fee29-1",
-			"whitelist:ics20-1",
-		},
-		{
-			"no middleware",
-			"ics20-1",
-			"",
-			"ics20-1",
-		},
-	}
-
-	for _, tc := range testCases {
-		mwVersion, appVersion := types.SplitChannelVersion(tc.version)
-		require.Equal(t, tc.mwVersion, mwVersion, "middleware version is unexpected for case: %s", tc.name)
-		require.Equal(t, tc.appVersion, appVersion, "app version is unexpected for case: %s", tc.name)
-	}
-}
-
-func TestMergeVersions(t *testing.T) {
-	testCases := []struct {
-		name     string
-		versions []string
-		merged   string
-	}{
-		{
-			"single version",
-			[]string{"ics20-1"},
-			"ics20-1",
-		},
-		{
-			"empty version",
-			[]string{},
-			"",
-		},
-		{
-			"two versions",
-			[]string{"fee29-1", "ics20-1"},
-			"fee29-1:ics20-1",
-		},
-		{
-			"multiple versions",
-			[]string{"fee29-1", "whitelist", "ics20-1"},
-			"fee29-1:whitelist:ics20-1",
-		},
-	}
-
-	for _, tc := range testCases {
-		actual := types.MergeChannelVersions(tc.versions...)
-		require.Equal(t, tc.merged, actual, "merged versions string does not equal expected value")
-	}
-}