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

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

api4/group.go

@@ -137,12 +137,32 @@ func patchGroup(c *Context, w http.ResponseWriter, r *http.Request) {
 	auditRec.AddMeta("group", group)
 
 	if groupPatch.AllowReference != nil && *groupPatch.AllowReference {
-		tmp := model.NewId()
 		if groupPatch.Name == nil {
-			tmp = strings.ReplaceAll(strings.ToLower(group.DisplayName), " ", "-")
+			tmp := strings.ReplaceAll(strings.ToLower(group.DisplayName), " ", "-")
+			groupPatch.Name = &tmp
+		} else {
+			if *groupPatch.Name == model.USER_NOTIFY_ALL || *groupPatch.Name == model.CHANNEL_MENTIONS_NOTIFY_PROP || *groupPatch.Name == model.USER_NOTIFY_HERE {
+				c.Err = model.NewAppError("Api4.patchGroup", "api.ldap_groups.existing_reserved_name_error", nil, "", http.StatusNotImplemented)
+				return
+			}
+			//check if a user already has this group name
+			user, _ := c.App.GetUserByUsername(*groupPatch.Name)
+			if user != nil {
+				c.Err = model.NewAppError("Api4.patchGroup", "api.ldap_groups.existing_user_name_error", nil, "", http.StatusNotImplemented)
+				return
+			}
+			//check if a mentionable group already has this name
+			searchOpts := model.GroupSearchOpts{
+				FilterAllowReference: true,
+			}
+			existingGroup, _ := c.App.GetGroupByName(*groupPatch.Name, searchOpts)
+			if existingGroup != nil {
+				c.Err = model.NewAppError("Api4.patchGroup", "api.ldap_groups.existing_group_name_error", nil, "", http.StatusNotImplemented)
+				return
+			}
 		}
-		groupPatch.Name = &tmp
 	}
+
 	group.Patch(groupPatch)
 
 	group, err = c.App.UpdateGroup(group)