Add more linters to improve code readability (#19989)

Add nakedret, unconvert, wastedassign, stylecheck and nolintlint linters to improve code readability

- nakedret - https://github.com/alexkohler/nakedret - nakedret is a Go static analysis tool to find naked returns in functions greater than a specified function length.
- unconvert - https://github.com/mdempsky/unconvert - Remove unnecessary type conversions
- wastedassign - https://github.com/sanposhiho/wastedassign -  wastedassign finds wasted assignment statements.
- notlintlint -  Reports ill-formed or insufficient nolint directives
- stylecheck - https://staticcheck.io/docs/checks/#ST - keep style consistent
  - excluded: [ST1003 - Poorly chosen identifier](https://staticcheck.io/docs/checks/#ST1003) and [ST1005 - Incorrectly formatted error string](https://staticcheck.io/docs/checks/#ST1005)

14 files changed, 116 insertions, 117 deletions

diff --git a/services/agit/agit.go b/services/agit/agit.go
index 4359557a1e..9f0ce75123 100644
--- a/services/agit/agit.go
+++ b/services/agit/agit.go
@@ -80,7 +80,7 @@ func ProcReceive(ctx context.Context, repo *repo_model.Repository, gitRepo *git.
 			continue
 		}
 
-		headBranch := ""
+		var headBranch string
 		userName := strings.ToLower(opts.UserName)
 
 		if len(curentTopicBranch) == 0 {
@@ -104,7 +104,7 @@ func ProcReceive(ctx context.Context, repo *repo_model.Repository, gitRepo *git.
 
 			// create a new pull request
 			if len(title) == 0 {
-				has := false
+				var has bool
 				title, has = opts.GitPushOptions["title"]
 				if !has || len(title) == 0 {
 					commit, err := gitRepo.GetCommit(opts.NewCommitIDs[i])
diff --git a/services/auth/source/ldap/source_search.go b/services/auth/source/ldap/source_search.go
index d01fd14c8b..988d56005e 100644
--- a/services/auth/source/ldap/source_search.go
+++ b/services/auth/source/ldap/source_search.go
@@ -34,7 +34,7 @@ type SearchResult struct {
 	LdapTeamRemove map[string][]string // organizations teams to remove
 }
 
-func (ls *Source) sanitizedUserQuery(username string) (string, bool) {
+func (source *Source) sanitizedUserQuery(username string) (string, bool) {
 	// See http://tools.ietf.org/search/rfc4515
 	badCharacters := "\x00()*\\"
 	if strings.ContainsAny(username, badCharacters) {
@@ -42,10 +42,10 @@ func (ls *Source) sanitizedUserQuery(username string) (string, bool) {
 		return "", false
 	}
 
-	return fmt.Sprintf(ls.Filter, username), true
+	return fmt.Sprintf(source.Filter, username), true
 }
 
-func (ls *Source) sanitizedUserDN(username string) (string, bool) {
+func (source *Source) sanitizedUserDN(username string) (string, bool) {
 	// See http://tools.ietf.org/search/rfc4514: "special characters"
 	badCharacters := "\x00()*\\,='\"#+;<>"
 	if strings.ContainsAny(username, badCharacters) {
@@ -53,10 +53,10 @@ func (ls *Source) sanitizedUserDN(username string) (string, bool) {
 		return "", false
 	}
 
-	return fmt.Sprintf(ls.UserDN, username), true
+	return fmt.Sprintf(source.UserDN, username), true
 }
 
-func (ls *Source) sanitizedGroupFilter(group string) (string, bool) {
+func (source *Source) sanitizedGroupFilter(group string) (string, bool) {
 	// See http://tools.ietf.org/search/rfc4515
 	badCharacters := "\x00*\\"
 	if strings.ContainsAny(group, badCharacters) {
@@ -67,7 +67,7 @@ func (ls *Source) sanitizedGroupFilter(group string) (string, bool) {
 	return group, true
 }
 
-func (ls *Source) sanitizedGroupDN(groupDn string) (string, bool) {
+func (source *Source) sanitizedGroupDN(groupDn string) (string, bool) {
 	// See http://tools.ietf.org/search/rfc4514: "special characters"
 	badCharacters := "\x00()*\\'\"#+;<>"
 	if strings.ContainsAny(groupDn, badCharacters) || strings.HasPrefix(groupDn, " ") || strings.HasSuffix(groupDn, " ") {
@@ -78,18 +78,18 @@ func (ls *Source) sanitizedGroupDN(groupDn string) (string, bool) {
 	return groupDn, true
 }
 
-func (ls *Source) findUserDN(l *ldap.Conn, name string) (string, bool) {
+func (source *Source) findUserDN(l *ldap.Conn, name string) (string, bool) {
 	log.Trace("Search for LDAP user: %s", name)
 
 	// A search for the user.
-	userFilter, ok := ls.sanitizedUserQuery(name)
+	userFilter, ok := source.sanitizedUserQuery(name)
 	if !ok {
 		return "", false
 	}
 
-	log.Trace("Searching for DN using filter %s and base %s", userFilter, ls.UserBase)
+	log.Trace("Searching for DN using filter %s and base %s", userFilter, source.UserBase)
 	search := ldap.NewSearchRequest(
-		ls.UserBase, ldap.ScopeWholeSubtree, ldap.NeverDerefAliases, 0, 0,
+		source.UserBase, ldap.ScopeWholeSubtree, ldap.NeverDerefAliases, 0, 0,
 		false, userFilter, []string{}, nil)
 
 	// Ensure we found a user
@@ -197,11 +197,11 @@ func checkRestricted(l *ldap.Conn, ls *Source, userDN string) bool {
 }
 
 // List all group memberships of a user
-func (ls *Source) listLdapGroupMemberships(l *ldap.Conn, uid string) []string {
+func (source *Source) listLdapGroupMemberships(l *ldap.Conn, uid string) []string {
 	var ldapGroups []string
-	groupFilter := fmt.Sprintf("(%s=%s)", ls.GroupMemberUID, uid)
+	groupFilter := fmt.Sprintf("(%s=%s)", source.GroupMemberUID, uid)
 	result, err := l.Search(ldap.NewSearchRequest(
-		ls.GroupDN,
+		source.GroupDN,
 		ldap.ScopeWholeSubtree,
 		ldap.NeverDerefAliases,
 		0,
@@ -228,9 +228,9 @@ func (ls *Source) listLdapGroupMemberships(l *ldap.Conn, uid string) []string {
 }
 
 // parse LDAP groups and return map of ldap groups to organizations teams
-func (ls *Source) mapLdapGroupsToTeams() map[string]map[string][]string {
+func (source *Source) mapLdapGroupsToTeams() map[string]map[string][]string {
 	ldapGroupsToTeams := make(map[string]map[string][]string)
-	err := json.Unmarshal([]byte(ls.GroupTeamMap), &ldapGroupsToTeams)
+	err := json.Unmarshal([]byte(source.GroupTeamMap), &ldapGroupsToTeams)
 	if err != nil {
 		log.Error("Failed to unmarshall LDAP teams map: %v", err)
 		return ldapGroupsToTeams
@@ -239,11 +239,11 @@ func (ls *Source) mapLdapGroupsToTeams() map[string]map[string][]string {
 }
 
 // getMappedMemberships : returns the organizations and teams to modify the users membership
-func (ls *Source) getMappedMemberships(l *ldap.Conn, uid string) (map[string][]string, map[string][]string) {
+func (source *Source) getMappedMemberships(l *ldap.Conn, uid string) (map[string][]string, map[string][]string) {
 	// get all LDAP group memberships for user
-	usersLdapGroups := ls.listLdapGroupMemberships(l, uid)
+	usersLdapGroups := source.listLdapGroupMemberships(l, uid)
 	// unmarshall LDAP group team map from configs
-	ldapGroupsToTeams := ls.mapLdapGroupsToTeams()
+	ldapGroupsToTeams := source.mapLdapGroupsToTeams()
 	membershipsToAdd := map[string][]string{}
 	membershipsToRemove := map[string][]string{}
 	for group, memberships := range ldapGroupsToTeams {
@@ -262,26 +262,26 @@ func (ls *Source) getMappedMemberships(l *ldap.Conn, uid string) (map[string][]s
 }
 
 // SearchEntry : search an LDAP source if an entry (name, passwd) is valid and in the specific filter
-func (ls *Source) SearchEntry(name, passwd string, directBind bool) *SearchResult {
+func (source *Source) SearchEntry(name, passwd string, directBind bool) *SearchResult {
 	// See https://tools.ietf.org/search/rfc4513#section-5.1.2
 	if len(passwd) == 0 {
 		log.Debug("Auth. failed for %s, password cannot be empty", name)
 		return nil
 	}
-	l, err := dial(ls)
+	l, err := dial(source)
 	if err != nil {
-		log.Error("LDAP Connect error, %s:%v", ls.Host, err)
-		ls.Enabled = false
+		log.Error("LDAP Connect error, %s:%v", source.Host, err)
+		source.Enabled = false
 		return nil
 	}
 	defer l.Close()
 
 	var userDN string
 	if directBind {
-		log.Trace("LDAP will bind directly via UserDN template: %s", ls.UserDN)
+		log.Trace("LDAP will bind directly via UserDN template: %s", source.UserDN)
 
 		var ok bool
-		userDN, ok = ls.sanitizedUserDN(name)
+		userDN, ok = source.sanitizedUserDN(name)
 
 		if !ok {
 			return nil
@@ -292,11 +292,11 @@ func (ls *Source) SearchEntry(name, passwd string, directBind bool) *SearchResul
 			return nil
 		}
 
-		if ls.UserBase != "" {
+		if source.UserBase != "" {
 			// not everyone has a CN compatible with input name so we need to find
 			// the real userDN in that case
 
-			userDN, ok = ls.findUserDN(l, name)
+			userDN, ok = source.findUserDN(l, name)
 			if !ok {
 				return nil
 			}
@@ -306,24 +306,24 @@ func (ls *Source) SearchEntry(name, passwd string, directBind bool) *SearchResul
 
 		var found bool
 
-		if ls.BindDN != "" && ls.BindPassword != "" {
-			err := l.Bind(ls.BindDN, ls.BindPassword)
+		if source.BindDN != "" && source.BindPassword != "" {
+			err := l.Bind(source.BindDN, source.BindPassword)
 			if err != nil {
-				log.Debug("Failed to bind as BindDN[%s]: %v", ls.BindDN, err)
+				log.Debug("Failed to bind as BindDN[%s]: %v", source.BindDN, err)
 				return nil
 			}
-			log.Trace("Bound as BindDN %s", ls.BindDN)
+			log.Trace("Bound as BindDN %s", source.BindDN)
 		} else {
 			log.Trace("Proceeding with anonymous LDAP search.")
 		}
 
-		userDN, found = ls.findUserDN(l, name)
+		userDN, found = source.findUserDN(l, name)
 		if !found {
 			return nil
 		}
 	}
 
-	if !ls.AttributesInBind {
+	if !source.AttributesInBind {
 		// binds user (checking password) before looking-up attributes in user context
 		err = bindUser(l, userDN, passwd)
 		if err != nil {
@@ -331,26 +331,26 @@ func (ls *Source) SearchEntry(name, passwd string, directBind bool) *SearchResul
 		}
 	}
 
-	userFilter, ok := ls.sanitizedUserQuery(name)
+	userFilter, ok := source.sanitizedUserQuery(name)
 	if !ok {
 		return nil
 	}
 
-	isAttributeSSHPublicKeySet := len(strings.TrimSpace(ls.AttributeSSHPublicKey)) > 0
-	isAtributeAvatarSet := len(strings.TrimSpace(ls.AttributeAvatar)) > 0
+	isAttributeSSHPublicKeySet := len(strings.TrimSpace(source.AttributeSSHPublicKey)) > 0
+	isAtributeAvatarSet := len(strings.TrimSpace(source.AttributeAvatar)) > 0
 
-	attribs := []string{ls.AttributeUsername, ls.AttributeName, ls.AttributeSurname, ls.AttributeMail}
-	if len(strings.TrimSpace(ls.UserUID)) > 0 {
-		attribs = append(attribs, ls.UserUID)
+	attribs := []string{source.AttributeUsername, source.AttributeName, source.AttributeSurname, source.AttributeMail}
+	if len(strings.TrimSpace(source.UserUID)) > 0 {
+		attribs = append(attribs, source.UserUID)
 	}
 	if isAttributeSSHPublicKeySet {
-		attribs = append(attribs, ls.AttributeSSHPublicKey)
+		attribs = append(attribs, source.AttributeSSHPublicKey)
 	}
 	if isAtributeAvatarSet {
-		attribs = append(attribs, ls.AttributeAvatar)
+		attribs = append(attribs, source.AttributeAvatar)
 	}
 
-	log.Trace("Fetching attributes '%v', '%v', '%v', '%v', '%v', '%v', '%v' with filter '%s' and base '%s'", ls.AttributeUsername, ls.AttributeName, ls.AttributeSurname, ls.AttributeMail, ls.AttributeSSHPublicKey, ls.AttributeAvatar, ls.UserUID, userFilter, userDN)
+	log.Trace("Fetching attributes '%v', '%v', '%v', '%v', '%v', '%v', '%v' with filter '%s' and base '%s'", source.AttributeUsername, source.AttributeName, source.AttributeSurname, source.AttributeMail, source.AttributeSSHPublicKey, source.AttributeAvatar, source.UserUID, userFilter, userDN)
 	search := ldap.NewSearchRequest(
 		userDN, ldap.ScopeWholeSubtree, ldap.NeverDerefAliases, 0, 0, false, userFilter,
 		attribs, nil)
@@ -372,30 +372,30 @@ func (ls *Source) SearchEntry(name, passwd string, directBind bool) *SearchResul
 	var sshPublicKey []string
 	var Avatar []byte
 
-	username := sr.Entries[0].GetAttributeValue(ls.AttributeUsername)
-	firstname := sr.Entries[0].GetAttributeValue(ls.AttributeName)
-	surname := sr.Entries[0].GetAttributeValue(ls.AttributeSurname)
-	mail := sr.Entries[0].GetAttributeValue(ls.AttributeMail)
-	uid := sr.Entries[0].GetAttributeValue(ls.UserUID)
-	if ls.UserUID == "dn" || ls.UserUID == "DN" {
+	username := sr.Entries[0].GetAttributeValue(source.AttributeUsername)
+	firstname := sr.Entries[0].GetAttributeValue(source.AttributeName)
+	surname := sr.Entries[0].GetAttributeValue(source.AttributeSurname)
+	mail := sr.Entries[0].GetAttributeValue(source.AttributeMail)
+	uid := sr.Entries[0].GetAttributeValue(source.UserUID)
+	if source.UserUID == "dn" || source.UserUID == "DN" {
 		uid = sr.Entries[0].DN
 	}
 
 	// Check group membership
-	if ls.GroupsEnabled && ls.GroupFilter != "" {
-		groupFilter, ok := ls.sanitizedGroupFilter(ls.GroupFilter)
+	if source.GroupsEnabled && source.GroupFilter != "" {
+		groupFilter, ok := source.sanitizedGroupFilter(source.GroupFilter)
 		if !ok {
 			return nil
 		}
-		groupDN, ok := ls.sanitizedGroupDN(ls.GroupDN)
+		groupDN, ok := source.sanitizedGroupDN(source.GroupDN)
 		if !ok {
 			return nil
 		}
 
-		log.Trace("Fetching groups '%v' with filter '%s' and base '%s'", ls.GroupMemberUID, groupFilter, groupDN)
+		log.Trace("Fetching groups '%v' with filter '%s' and base '%s'", source.GroupMemberUID, groupFilter, groupDN)
 		groupSearch := ldap.NewSearchRequest(
 			groupDN, ldap.ScopeWholeSubtree, ldap.NeverDerefAliases, 0, 0, false, groupFilter,
-			[]string{ls.GroupMemberUID},
+			[]string{source.GroupMemberUID},
 			nil)
 
 		srg, err := l.Search(groupSearch)
@@ -410,8 +410,8 @@ func (ls *Source) SearchEntry(name, passwd string, directBind bool) *SearchResul
 		isMember := false
 	Entries:
 		for _, group := range srg.Entries {
-			for _, member := range group.GetAttributeValues(ls.GroupMemberUID) {
-				if (ls.UserUID == "dn" && member == sr.Entries[0].DN) || member == uid {
+			for _, member := range group.GetAttributeValues(source.GroupMemberUID) {
+				if (source.UserUID == "dn" && member == sr.Entries[0].DN) || member == uid {
 					isMember = true
 					break Entries
 				}
@@ -425,25 +425,25 @@ func (ls *Source) SearchEntry(name, passwd string, directBind bool) *SearchResul
 	}
 
 	if isAttributeSSHPublicKeySet {
-		sshPublicKey = sr.Entries[0].GetAttributeValues(ls.AttributeSSHPublicKey)
+		sshPublicKey = sr.Entries[0].GetAttributeValues(source.AttributeSSHPublicKey)
 	}
-	isAdmin := checkAdmin(l, ls, userDN)
+	isAdmin := checkAdmin(l, source, userDN)
 	var isRestricted bool
 	if !isAdmin {
-		isRestricted = checkRestricted(l, ls, userDN)
+		isRestricted = checkRestricted(l, source, userDN)
 	}
 
 	if isAtributeAvatarSet {
-		Avatar = sr.Entries[0].GetRawAttributeValue(ls.AttributeAvatar)
+		Avatar = sr.Entries[0].GetRawAttributeValue(source.AttributeAvatar)
 	}
 
 	teamsToAdd := make(map[string][]string)
 	teamsToRemove := make(map[string][]string)
-	if ls.GroupsEnabled && (ls.GroupTeamMap != "" || ls.GroupTeamMapRemoval) {
-		teamsToAdd, teamsToRemove = ls.getMappedMemberships(l, uid)
+	if source.GroupsEnabled && (source.GroupTeamMap != "" || source.GroupTeamMapRemoval) {
+		teamsToAdd, teamsToRemove = source.getMappedMemberships(l, uid)
 	}
 
-	if !directBind && ls.AttributesInBind {
+	if !directBind && source.AttributesInBind {
 		// binds user (checking password) after looking-up attributes in BindDN context
 		err = bindUser(l, userDN, passwd)
 		if err != nil {
@@ -467,52 +467,52 @@ func (ls *Source) SearchEntry(name, passwd string, directBind bool) *SearchResul
 }
 
 // UsePagedSearch returns if need to use paged search
-func (ls *Source) UsePagedSearch() bool {
-	return ls.SearchPageSize > 0
+func (source *Source) UsePagedSearch() bool {
+	return source.SearchPageSize > 0
 }
 
 // SearchEntries : search an LDAP source for all users matching userFilter
-func (ls *Source) SearchEntries() ([]*SearchResult, error) {
-	l, err := dial(ls)
+func (source *Source) SearchEntries() ([]*SearchResult, error) {
+	l, err := dial(source)
 	if err != nil {
-		log.Error("LDAP Connect error, %s:%v", ls.Host, err)
-		ls.Enabled = false
+		log.Error("LDAP Connect error, %s:%v", source.Host, err)
+		source.Enabled = false
 		return nil, err
 	}
 	defer l.Close()
 
-	if ls.BindDN != "" && ls.BindPassword != "" {
-		err := l.Bind(ls.BindDN, ls.BindPassword)
+	if source.BindDN != "" && source.BindPassword != "" {
+		err := l.Bind(source.BindDN, source.BindPassword)
 		if err != nil {
-			log.Debug("Failed to bind as BindDN[%s]: %v", ls.BindDN, err)
+			log.Debug("Failed to bind as BindDN[%s]: %v", source.BindDN, err)
 			return nil, err
 		}
-		log.Trace("Bound as BindDN %s", ls.BindDN)
+		log.Trace("Bound as BindDN %s", source.BindDN)
 	} else {
 		log.Trace("Proceeding with anonymous LDAP search.")
 	}
 
-	userFilter := fmt.Sprintf(ls.Filter, "*")
+	userFilter := fmt.Sprintf(source.Filter, "*")
 
-	isAttributeSSHPublicKeySet := len(strings.TrimSpace(ls.AttributeSSHPublicKey)) > 0
-	isAtributeAvatarSet := len(strings.TrimSpace(ls.AttributeAvatar)) > 0
+	isAttributeSSHPublicKeySet := len(strings.TrimSpace(source.AttributeSSHPublicKey)) > 0
+	isAtributeAvatarSet := len(strings.TrimSpace(source.AttributeAvatar)) > 0
 
-	attribs := []string{ls.AttributeUsername, ls.AttributeName, ls.AttributeSurname, ls.AttributeMail, ls.UserUID}
+	attribs := []string{source.AttributeUsername, source.AttributeName, source.AttributeSurname, source.AttributeMail, source.UserUID}
 	if isAttributeSSHPublicKeySet {
-		attribs = append(attribs, ls.AttributeSSHPublicKey)
+		attribs = append(attribs, source.AttributeSSHPublicKey)
 	}
 	if isAtributeAvatarSet {
-		attribs = append(attribs, ls.AttributeAvatar)
+		attribs = append(attribs, source.AttributeAvatar)
 	}
 
-	log.Trace("Fetching attributes '%v', '%v', '%v', '%v', '%v', '%v' with filter %s and base %s", ls.AttributeUsername, ls.AttributeName, ls.AttributeSurname, ls.AttributeMail, ls.AttributeSSHPublicKey, ls.AttributeAvatar, userFilter, ls.UserBase)
+	log.Trace("Fetching attributes '%v', '%v', '%v', '%v', '%v', '%v' with filter %s and base %s", source.AttributeUsername, source.AttributeName, source.AttributeSurname, source.AttributeMail, source.AttributeSSHPublicKey, source.AttributeAvatar, userFilter, source.UserBase)
 	search := ldap.NewSearchRequest(
-		ls.UserBase, ldap.ScopeWholeSubtree, ldap.NeverDerefAliases, 0, 0, false, userFilter,
+		source.UserBase, ldap.ScopeWholeSubtree, ldap.NeverDerefAliases, 0, 0, false, userFilter,
 		attribs, nil)
 
 	var sr *ldap.SearchResult
-	if ls.UsePagedSearch() {
-		sr, err = l.SearchWithPaging(search, ls.SearchPageSize)
+	if source.UsePagedSearch() {
+		sr, err = l.SearchWithPaging(search, source.SearchPageSize)
 	} else {
 		sr, err = l.Search(search)
 	}
@@ -526,30 +526,30 @@ func (ls *Source) SearchEntries() ([]*SearchResult, error) {
 	for i, v := range sr.Entries {
 		teamsToAdd := make(map[string][]string)
 		teamsToRemove := make(map[string][]string)
-		if ls.GroupsEnabled && (ls.GroupTeamMap != "" || ls.GroupTeamMapRemoval) {
-			userAttributeListedInGroup := v.GetAttributeValue(ls.UserUID)
-			if ls.UserUID == "dn" || ls.UserUID == "DN" {
+		if source.GroupsEnabled && (source.GroupTeamMap != "" || source.GroupTeamMapRemoval) {
+			userAttributeListedInGroup := v.GetAttributeValue(source.UserUID)
+			if source.UserUID == "dn" || source.UserUID == "DN" {
 				userAttributeListedInGroup = v.DN
 			}
-			teamsToAdd, teamsToRemove = ls.getMappedMemberships(l, userAttributeListedInGroup)
+			teamsToAdd, teamsToRemove = source.getMappedMemberships(l, userAttributeListedInGroup)
 		}
 		result[i] = &SearchResult{
-			Username:       v.GetAttributeValue(ls.AttributeUsername),
-			Name:           v.GetAttributeValue(ls.AttributeName),
-			Surname:        v.GetAttributeValue(ls.AttributeSurname),
-			Mail:           v.GetAttributeValue(ls.AttributeMail),
-			IsAdmin:        checkAdmin(l, ls, v.DN),
+			Username:       v.GetAttributeValue(source.AttributeUsername),
+			Name:           v.GetAttributeValue(source.AttributeName),
+			Surname:        v.GetAttributeValue(source.AttributeSurname),
+			Mail:           v.GetAttributeValue(source.AttributeMail),
+			IsAdmin:        checkAdmin(l, source, v.DN),
 			LdapTeamAdd:    teamsToAdd,
 			LdapTeamRemove: teamsToRemove,
 		}
 		if !result[i].IsAdmin {
-			result[i].IsRestricted = checkRestricted(l, ls, v.DN)
+			result[i].IsRestricted = checkRestricted(l, source, v.DN)
 		}
 		if isAttributeSSHPublicKeySet {
-			result[i].SSHPublicKey = v.GetAttributeValues(ls.AttributeSSHPublicKey)
+			result[i].SSHPublicKey = v.GetAttributeValues(source.AttributeSSHPublicKey)
 		}
 		if isAtributeAvatarSet {
-			result[i].Avatar = v.GetRawAttributeValue(ls.AttributeAvatar)
+			result[i].Avatar = v.GetRawAttributeValue(source.AttributeAvatar)
 		}
 		result[i].LowerName = strings.ToLower(result[i].Username)
 	}
diff --git a/services/auth/sspi_windows.go b/services/auth/sspi_windows.go
index 7c9529a76b..7e31378b6c 100644
--- a/services/auth/sspi_windows.go
+++ b/services/auth/sspi_windows.go
@@ -180,7 +180,7 @@ func (s *SSPI) shouldAuthenticate(req *http.Request) (shouldAuth bool) {
 	} else if middleware.IsAPIPath(req) || isAttachmentDownload(req) {
 		shouldAuth = true
 	}
-	return
+	return shouldAuth
 }
 
 // newUser creates a new user object for the purpose of automatic registration
diff --git a/services/automerge/automerge.go b/services/automerge/automerge.go
index d0f83f4a93..ca008ebfe6 100644
--- a/services/automerge/automerge.go
+++ b/services/automerge/automerge.go
@@ -82,7 +82,7 @@ func ScheduleAutoMerge(ctx context.Context, doer *user_model.User, pull *issues_
 		_, err = issues_model.CreateAutoMergeComment(ctx, issues_model.CommentTypePRScheduledToAutoMerge, pull, doer)
 		return err
 	}, ctx)
-	return
+	return scheduled, err
 }
 
 // RemoveScheduledAutoMerge cancels a previously scheduled pull request
diff --git a/services/gitdiff/gitdiff.go b/services/gitdiff/gitdiff.go
index 37dc0e114d..6e8c149dab 100644
--- a/services/gitdiff/gitdiff.go
+++ b/services/gitdiff/gitdiff.go
@@ -1011,7 +1011,7 @@ parsingLoop:
 
 func skipToNextDiffHead(input *bufio.Reader) (line string, err error) {
 	// need to skip until the next cmdDiffHead
-	isFragment, wasFragment := false, false
+	var isFragment, wasFragment bool
 	var lineBytes []byte
 	for {
 		lineBytes, isFragment, err = input.ReadLine()
@@ -1036,7 +1036,7 @@ func skipToNextDiffHead(input *bufio.Reader) (line string, err error) {
 		}
 		line += tail
 	}
-	return
+	return line, err
 }
 
 func parseHunks(curFile *DiffFile, maxLines, maxLineCharacters int, input *bufio.Reader) (lineBytes []byte, isFragment bool, err error) {
@@ -1257,8 +1257,7 @@ func createDiffFile(diff *Diff, line string) *DiffFile {
 
 	rd := strings.NewReader(line[len(cmdDiffHead):] + " ")
 	curFile.Type = DiffFileChange
-	oldNameAmbiguity := false
-	newNameAmbiguity := false
+	var oldNameAmbiguity, newNameAmbiguity bool
 
 	curFile.OldName, oldNameAmbiguity = readFileName(rd)
 	curFile.Name, newNameAmbiguity = readFileName(rd)
diff --git a/services/issue/assignee.go b/services/issue/assignee.go
index 7c00f472dd..aefd8cff9a 100644
--- a/services/issue/assignee.go
+++ b/services/issue/assignee.go
@@ -59,7 +59,7 @@ func ToggleAssignee(issue *issues_model.Issue, doer *user_model.User, assigneeID
 
 	notification.NotifyIssueChangeAssignee(doer, issue, assignee, removed, comment)
 
-	return
+	return removed, comment, err
 }
 
 // ReviewRequest add or remove a review request from a user for this PR, and make comment for it.
@@ -78,7 +78,7 @@ func ReviewRequest(issue *issues_model.Issue, doer, reviewer *user_model.User, i
 		notification.NotifyPullReviewRequest(doer, issue, reviewer, isAdd, comment)
 	}
 
-	return
+	return comment, err
 }
 
 // IsValidReviewRequest Check permission for ReviewRequest
@@ -262,5 +262,5 @@ func TeamReviewRequest(issue *issues_model.Issue, doer *user_model.User, reviewe
 		notification.NotifyPullReviewRequest(doer, issue, member, isAdd, comment)
 	}
 
-	return
+	return comment, err
 }
diff --git a/services/issue/issue.go b/services/issue/issue.go
index 467bc14b84..7131829b03 100644
--- a/services/issue/issue.go
+++ b/services/issue/issue.go
@@ -129,7 +129,7 @@ func UpdateAssignees(issue *issues_model.Issue, oneAssignee string, multipleAssi
 		}
 	}
 
-	return
+	return err
 }
 
 // DeleteIssue deletes an issue
diff --git a/services/mailer/mail.go b/services/mailer/mail.go
index 81cfb2e31a..f936229551 100644
--- a/services/mailer/mail.go
+++ b/services/mailer/mail.go
@@ -287,7 +287,7 @@ func composeIssueCommentMessages(ctx *mailCommentContext, lang string, recipient
 	}
 
 	var mailSubject bytes.Buffer
-	if err := subjectTemplates.ExecuteTemplate(&mailSubject, string(tplName), mailMeta); err == nil {
+	if err := subjectTemplates.ExecuteTemplate(&mailSubject, tplName, mailMeta); err == nil {
 		subject = sanitizeSubject(mailSubject.String())
 		if subject == "" {
 			subject = fallback
@@ -302,8 +302,8 @@ func composeIssueCommentMessages(ctx *mailCommentContext, lang string, recipient
 
 	var mailBody bytes.Buffer
 
-	if err := bodyTemplates.ExecuteTemplate(&mailBody, string(tplName), mailMeta); err != nil {
-		log.Error("ExecuteTemplate [%s]: %v", string(tplName)+"/body", err)
+	if err := bodyTemplates.ExecuteTemplate(&mailBody, tplName, mailMeta); err != nil {
+		log.Error("ExecuteTemplate [%s]: %v", tplName+"/body", err)
 	}
 
 	// Make sure to compose independent messages to avoid leaking user emails
@@ -498,5 +498,5 @@ func actionToTemplate(issue *issues_model.Issue, actionType models.ActionType,
 	if !ok {
 		template = "issue/default"
 	}
-	return
+	return typeName, name, template
 }
diff --git a/services/mailer/mail_test.go b/services/mailer/mail_test.go
index 83955a5896..93837ba8c4 100644
--- a/services/mailer/mail_test.go
+++ b/services/mailer/mail_test.go
@@ -61,7 +61,7 @@ func prepareMailerTest(t *testing.T) (doer *user_model.User, repo *repo_model.Re
 	issue = unittest.AssertExistsAndLoadBean(t, &issues_model.Issue{ID: 1, Repo: repo, Poster: doer}).(*issues_model.Issue)
 	assert.NoError(t, issue.LoadRepo(db.DefaultContext))
 	comment = unittest.AssertExistsAndLoadBean(t, &issues_model.Comment{ID: 2, Issue: issue}).(*issues_model.Comment)
-	return
+	return doer, repo, issue, comment
 }
 
 func TestComposeIssueCommentMessage(t *testing.T) {
diff --git a/services/migrations/onedev.go b/services/migrations/onedev.go
index d4b30939ce..a46ba35f72 100644
--- a/services/migrations/onedev.go
+++ b/services/migrations/onedev.go
@@ -38,7 +38,7 @@ func (f *OneDevDownloaderFactory) New(ctx context.Context, opts base.MigrateOpti
 		return nil, err
 	}
 
-	repoName := ""
+	var repoName string
 
 	fields := strings.Split(strings.Trim(u.Path, "/"), "/")
 	if len(fields) == 2 && fields[0] == "projects" {
diff --git a/services/pull/merge.go b/services/pull/merge.go
index e8bb3a1cdd..4cd4e3bd7e 100644
--- a/services/pull/merge.go
+++ b/services/pull/merge.go
@@ -358,7 +358,7 @@ func rawMerge(ctx context.Context, pr *issues_model.PullRequest, doer *user_mode
 	committer := sig
 
 	// Determine if we should sign
-	signArg := ""
+	var signArg string
 	sign, keyID, signer, _ := asymkey_service.SignMerge(ctx, pr, doer, tmpBasePath, "HEAD", trackingBranch)
 	if sign {
 		signArg = "-S" + keyID
@@ -858,7 +858,7 @@ func MergedManually(pr *issues_model.PullRequest, doer *user_model.User, baseGit
 		pr.Merger = doer
 		pr.MergerID = doer.ID
 
-		merged := false
+		var merged bool
 		if merged, err = pr.SetMerged(ctx); err != nil {
 			return err
 		} else if !merged {
diff --git a/services/pull/review.go b/services/pull/review.go
index 9cb58fa3a1..6bb8877b0f 100644
--- a/services/pull/review.go
+++ b/services/pull/review.go
@@ -318,5 +318,5 @@ func DismissReview(ctx context.Context, reviewID int64, message string, doer *us
 
 	notification.NotifyPullRevieweDismiss(doer, review, comment)
 
-	return
+	return comment, err
 }
diff --git a/services/task/migrate.go b/services/task/migrate.go
index 6f35134525..651681ef65 100644
--- a/services/task/migrate.go
+++ b/services/task/migrate.go
@@ -139,5 +139,5 @@ func runMigrateTask(t *models.Task) (err error) {
 
 	// do not be tempted to coalesce this line with the return
 	err = handleCreateError(t.Owner, err)
-	return
+	return err
 }
diff --git a/services/webhook/webhook.go b/services/webhook/webhook.go
index 68cfe147aa..767c3701f3 100644
--- a/services/webhook/webhook.go
+++ b/services/webhook/webhook.go
@@ -70,7 +70,7 @@ var webhooks = map[webhook_model.HookType]*webhook{
 
 // RegisterWebhook registers a webhook
 func RegisterWebhook(name string, webhook *webhook) {
-	webhooks[webhook_model.HookType(name)] = webhook
+	webhooks[name] = webhook
 }
 
 // IsValidHookTaskType returns true if a webhook registered
@@ -78,7 +78,7 @@ func IsValidHookTaskType(name string) bool {
 	if name == webhook_model.GITEA || name == webhook_model.GOGS {
 		return true
 	}
-	_, ok := webhooks[webhook_model.HookType(name)]
+	_, ok := webhooks[name]
 	return ok
 }