store: guests will only receive results of which channels they are in (#20295)

* store: guests will only receive results of which channels they are in

* api4/channel_test: add test case for guest accounts channel autocomplete

* apply to searchengine and also for AutocompleteInTeam

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

app/channel.go

@@ -2781,7 +2781,12 @@ func (a *App) AutocompleteChannels(userID, term string) (model.ChannelListWithTe
 	includeDeleted := *a.Config().TeamSettings.ExperimentalViewArchivedChannels
 	term = strings.TrimSpace(term)
 
-	channelList, err := a.Srv().Store.Channel().Autocomplete(userID, term, includeDeleted)
+	user, appErr := a.GetUser(userID)
+	if appErr != nil {
+		return nil, appErr
+	}
+
+	channelList, err := a.Srv().Store.Channel().Autocomplete(userID, term, includeDeleted, user.IsGuest())
 	if err != nil {
 		return nil, model.NewAppError("AutocompleteChannels", "app.channel.search.app_error", nil, err.Error(), http.StatusInternalServerError)
 	}
@@ -2793,7 +2798,12 @@ func (a *App) AutocompleteChannelsForTeam(teamID, userID, term string) (model.Ch
 	includeDeleted := *a.Config().TeamSettings.ExperimentalViewArchivedChannels
 	term = strings.TrimSpace(term)
 
-	channelList, err := a.Srv().Store.Channel().AutocompleteInTeam(teamID, userID, term, includeDeleted)
+	user, appErr := a.GetUser(userID)
+	if appErr != nil {
+		return nil, appErr
+	}
+
+	channelList, err := a.Srv().Store.Channel().AutocompleteInTeam(teamID, userID, term, includeDeleted, user.IsGuest())
 	if err != nil {
 		return nil, model.NewAppError("AutocompleteChannels", "app.channel.search.app_error", nil, err.Error(), http.StatusInternalServerError)
 	}