MM-52532: Fix golangci warnings (#23709)

https://mattermost.atlassian.net/browse/MM-52532

- Replace golint with revive
- Add makezero linter
- Fix all the required linter failures

Some issues in enterprise and public modules
are yet to be fixed. We send this to expediate things.

server/public/model/bot.go

@@ -197,8 +197,8 @@ func BotFromUser(u *User) *Bot {
 // Etag computes the etag for a list of bots.
 func (l *BotList) Etag() string {
 	id := "0"
-	var t int64 = 0
-	var delta int64 = 0
+	var t int64
+	var delta int64
 
 	for _, v := range *l {
 		if v.UpdateAt > t {

server/public/model/channel_count.go

@@ -31,7 +31,7 @@ func (o *ChannelCounts) Etag() string {
 
 	md5Counts := fmt.Sprintf("%x", md5.Sum([]byte(str)))
 
-	var update int64 = 0
+	var update int64
 	for _, u := range o.UpdateTimes {
 		if u > update {
 			update = u

server/public/model/channel_data.go

@@ -9,7 +9,7 @@ type ChannelData struct {
 }
 
 func (o *ChannelData) Etag() string {
-	var mt int64 = 0
+	var mt int64
 	if o.Member != nil {
 		mt = o.Member.LastUpdateAt
 	}

server/public/model/channel_list.go

@@ -8,8 +8,8 @@ type ChannelList []*Channel
 func (o *ChannelList) Etag() string {
 
 	id := "0"
-	var t int64 = 0
-	var delta int64 = 0
+	var t int64
+	var delta int64
 
 	for _, v := range *o {
 		if v.LastPostAt > t {
@@ -32,8 +32,8 @@ type ChannelListWithTeamData []*ChannelWithTeamData
 func (o *ChannelListWithTeamData) Etag() string {
 
 	id := "0"
-	var t int64 = 0
-	var delta int64 = 0
+	var t int64
+	var delta int64
 
 	for _, v := range *o {
 		if v.LastPostAt > t {

server/public/model/integration_action.go

@@ -434,7 +434,7 @@ func encryptPostActionCookie(plain string, secret []byte) (string, error) {
 
 	sealed := aesgcm.Seal(nil, nonce, []byte(plain), nil)
 
-	combined := append(nonce, sealed...)
+	combined := append(nonce, sealed...) //nolint:makezero
 	encoded := make([]byte, base64.StdEncoding.EncodedLen(len(combined)))
 	base64.StdEncoding.Encode(encoded, combined)
 

server/public/model/notify_admin.go

@@ -26,13 +26,13 @@ const (
 	PluginFeature                      = MattermostFeature("mattermost.feature.plugin")
 )
 
-var validSKUs map[string]struct{} = map[string]struct{}{
+var validSKUs = map[string]struct{}{
 	LicenseShortSkuProfessional: {},
 	LicenseShortSkuEnterprise:   {},
 }
 
 // These are the features a non admin would typically ping an admin about
-var paidFeatures map[MattermostFeature]struct{} = map[MattermostFeature]struct{}{
+var paidFeatures = map[MattermostFeature]struct{}{
 	PaidFeatureGuestAccounts:           {},
 	PaidFeatureCustomUsergroups:        {},
 	PaidFeatureCreateMultipleTeams:     {},

server/public/model/post.go

@@ -203,7 +203,7 @@ type AnalyticsPostCountsOptions struct {
 }
 
 func (o *PostPatch) WithRewrittenImageURLs(f func(string) string) *PostPatch {
-	copy := *o
+	copy := *o //nolint:revive
 	if copy.Message != nil {
 		*copy.Message = RewriteImageURLs(*o.Message, f)
 	}
@@ -292,13 +292,13 @@ func (o *Post) ShallowCopy(dst *Post) error {
 
 // Clone shallowly copies the post and returns the copy.
 func (o *Post) Clone() *Post {
-	copy := &Post{}
+	copy := &Post{} //nolint:revive
 	o.ShallowCopy(copy)
 	return copy
 }
 
 func (o *Post) ToJSON() (string, error) {
-	copy := o.Clone()
+	copy := o.Clone() //nolint:revive
 	copy.StripActionIntegrations()
 	b, err := json.Marshal(copy)
 	return string(b), err

server/public/model/remote_cluster.go

@@ -271,7 +271,7 @@ func (rci *RemoteClusterInvite) Encrypt(password string) ([]byte, error) {
 	// prefix the nonce to the cyphertext so we don't need to keep track of it.
 	sealed := gcm.Seal(nonce, nonce, raw, nil)
 
-	return append(salt, sealed...), nil
+	return append(salt, sealed...), nil //nolint:makezero
 }
 
 func (rci *RemoteClusterInvite) Decrypt(encrypted []byte, password string) error {

server/public/model/team.go

@@ -93,7 +93,7 @@ type TeamsWithCount struct {
 }
 
 func (o *Invites) ToEmailList() []string {
-	emailList := make([]string, len(o.Invites))
+	emailList := make([]string, 0, len(o.Invites))
 	for _, invite := range o.Invites {
 		emailList = append(emailList, invite["email"])
 	}

server/public/model/version.go

@@ -113,7 +113,7 @@ var versions = []string{
 	"0.5.0",
 }
 
-var CurrentVersion string = versions[0]
+var CurrentVersion = versions[0]
 var BuildNumber string
 var BuildDate string
 var BuildHash string

server/public/model/websocket_client_test.go

@@ -114,12 +114,12 @@ func TestWebSocketClose(t *testing.T) {
 
 	waitForResponses := func(doneChan chan struct{}, cli *WebSocketClient) {
 		go func() {
-			for range cli.EventChannel {
+			for range cli.EventChannel { //nolint:revive
 			}
 			doneChan <- struct{}{}
 		}()
 		go func() {
-			for range cli.ResponseChannel {
+			for range cli.ResponseChannel { //nolint:revive
 			}
 			doneChan <- struct{}{}
 		}()

server/public/model/websocket_message_test.go

@@ -36,39 +36,39 @@ func TestWebSocketEvent(t *testing.T) {
 func TestWebSocketEventImmutable(t *testing.T) {
 	m := NewWebSocketEvent("some_event", NewId(), NewId(), NewId(), nil, "")
 
-	new := m.SetEvent("new_event")
-	if new == m {
+	newM := m.SetEvent("new_event")
+	if newM == m {
 		require.Fail(t, "pointers should not be the same")
 	}
-	require.NotEqual(t, m.EventType(), new.EventType())
-	require.Equal(t, new.EventType(), "new_event")
+	require.NotEqual(t, m.EventType(), newM.EventType())
+	require.Equal(t, newM.EventType(), "new_event")
 
-	new = m.SetSequence(45)
-	if new == m {
+	newM = m.SetSequence(45)
+	if newM == m {
 		require.Fail(t, "pointers should not be the same")
 	}
-	require.NotEqual(t, m.GetSequence(), new.GetSequence())
-	require.Equal(t, new.GetSequence(), int64(45))
+	require.NotEqual(t, m.GetSequence(), newM.GetSequence())
+	require.Equal(t, newM.GetSequence(), int64(45))
 
 	broadcast := &WebsocketBroadcast{}
-	new = m.SetBroadcast(broadcast)
-	if new == m {
+	newM = m.SetBroadcast(broadcast)
+	if newM == m {
 		require.Fail(t, "pointers should not be the same")
 	}
-	require.NotEqual(t, m.GetBroadcast(), new.GetBroadcast())
-	require.Equal(t, new.GetBroadcast(), broadcast)
+	require.NotEqual(t, m.GetBroadcast(), newM.GetBroadcast())
+	require.Equal(t, newM.GetBroadcast(), broadcast)
 
 	data := map[string]any{
 		"key":  "val",
 		"key2": "val2",
 	}
-	new = m.SetData(data)
-	if new == m {
+	newM = m.SetData(data)
+	if newM == m {
 		require.Fail(t, "pointers should not be the same")
 	}
-	require.NotEqual(t, m, new)
-	require.Equal(t, new.data, data)
-	require.Equal(t, new.data, new.GetData())
+	require.NotEqual(t, m, newM)
+	require.Equal(t, newM.data, data)
+	require.Equal(t, newM.data, newM.GetData())
 
 	copy := m.Copy()
 	if copy == m {