MM-23816: Group Mentions: Add ability to rename group names (#14338)

* MM-23816: Group Mentions: Add ability to rename group names

model/group.go

@@ -7,6 +7,7 @@ import (
 	"encoding/json"
 	"io"
 	"net/http"
+	"regexp"
 )
 
 const (
@@ -103,8 +104,9 @@ func (group *Group) Patch(patch *GroupPatch) {
 }
 
 func (group *Group) IsValidForCreate() *AppError {
-	if l := len(group.Name); l == 0 || l > GroupNameMaxLength {
-		return NewAppError("Group.IsValidForCreate", "model.group.name.app_error", map[string]interface{}{"GroupNameMaxLength": GroupNameMaxLength}, "", http.StatusBadRequest)
+	err := group.IsValidName()
+	if err != nil {
+		return err
 	}
 
 	if l := len(group.DisplayName); l == 0 || l > GroupDisplayNameMaxLength {
@@ -158,6 +160,20 @@ func (group *Group) IsValidForUpdate() *AppError {
 	return nil
 }
 
+var validGroupnameChars = regexp.MustCompile(`^[a-z0-9\.\-_]+$`)
+
+func (group *Group) IsValidName() *AppError {
+	if l := len(group.Name); l == 0 || l > GroupNameMaxLength {
+		return NewAppError("Group.IsValidName", "model.group.name.app_error", map[string]interface{}{"GroupNameMaxLength": GroupNameMaxLength}, "", http.StatusBadRequest)
+	}
+
+	if !validGroupnameChars.MatchString(group.Name) {
+		return NewAppError("Group.IsValidName", "model.group.name.invalid_chars.app_error", nil, "", http.StatusBadRequest)
+	}
+
+	return nil
+}
+
 func GroupFromJson(data io.Reader) *Group {
 	var group *Group
 	json.NewDecoder(data).Decode(&group)