MM-54502 - Update regex to force first character to be alpha (#24675)

Automatic Merge

server/public/model/user.go

@@ -453,7 +453,7 @@ func (u *User) PreSave() *AppError {
 	}
 
 	if u.Username == "" {
-		u.Username = NewId()
+		u.Username = NewUsername()
 	}
 
 	if u.AuthData != nil && *u.AuthData == "" {
@@ -972,7 +972,8 @@ func HashPassword(password string) (string, error) {
 }
 
 var validUsernameChars = regexp.MustCompile(`^[a-z0-9\.\-_]+$`)
-var validUsernameCharsForRemote = regexp.MustCompile(`^[a-z0-9\.\-_:]+$`)
+var validUsername = regexp.MustCompile(`^[a-z][a-z0-9\.\-_]*$`)
+var validUsernameCharsForRemote = regexp.MustCompile(`^[a-z][a-z0-9\.\-_:]*$`)
 
 var restrictedUsernames = map[string]struct{}{
 	"all":       {},
@@ -986,7 +987,7 @@ func IsValidUsername(s string) bool {
 		return false
 	}
 
-	if !validUsernameChars.MatchString(s) {
+	if !validUsername.MatchString(s) {
 		return false
 	}
 
@@ -1028,7 +1029,7 @@ func CleanUsername(logger mlog.LoggerIFace, username string) string {
 	s = strings.Trim(s, "-")
 
 	if !IsValidUsername(s) {
-		s = "a" + NewId()
+		s = NewUsername()
 		logger.Warn("Generating new username since provided username was invalid",
 			mlog.String("provided_username", username), mlog.String("new_username", s))
 	}

server/public/model/user_test.go

@@ -252,11 +252,11 @@ func TestUserIsValid(t *testing.T) {
 	appErr = user.IsValid()
 	require.True(t, HasExpectedUserIsValidError(appErr, "username", user.Id, user.Username), "expected user is valid error: %s", appErr.Error())
 
-	user.Username = NewId() + "^hello#"
+	user.Username = NewUsername() + "^hello#"
 	appErr = user.IsValid()
 	require.True(t, HasExpectedUserIsValidError(appErr, "username", user.Id, user.Username), "expected user is valid error: %s", appErr.Error())
 
-	user.Username = NewId()
+	user.Username = NewUsername()
 	appErr = user.IsValid()
 	require.True(t, HasExpectedUserIsValidError(appErr, "email", user.Id, user.Email), "expected user is valid error: %s", appErr.Error())
 
@@ -429,9 +429,9 @@ var usernames = []usernamesTest{
 	{"spin-punch", true, true},
 	{"sp", true, true},
 	{"s", true, true},
-	{"1spin-punch", true, true},
-	{"-spin-punch", true, true},
-	{".spin-punch", true, true},
+	{"1spin-punch", false, false},
+	{"-spin-punch", false, false},
+	{".spin-punch", false, false},
 	{"Spin-punch", false, false},
 	{"spin punch-", false, false},
 	{"spin_punch", true, true},

server/public/model/utils.go

@@ -383,6 +383,11 @@ func NewId() string {
 	return encoding.EncodeToString(uuid.NewRandom())
 }
 
+// NewUsername is a NewId prefixed with a letter to make valid username
+func NewUsername() string {
+	return "a" + NewId()
+}
+
 // NewRandomTeamName is a NewId that will be a valid team name.
 func NewRandomTeamName() string {
 	teamName := NewId()