Adds a feature flag to control availability of DMs in shared channels (#28920)

* Adds a feature flag to control availability of DMs in shared channels

* Reverse feature flag wording

server/channels/app/channel.go

@@ -424,7 +424,7 @@ func (a *App) createDirectChannel(c request.CTX, userID string, otherUserID stri
 }
 
 func (a *App) createDirectChannelWithUser(c request.CTX, user, otherUser *model.User, channelOptions ...model.ChannelOption) (*model.Channel, *model.AppError) {
-	if user.IsRemote() || otherUser.IsRemote() {
+	if !a.Config().FeatureFlags.EnableSharedChannelsDMs && (user.IsRemote() || otherUser.IsRemote()) {
 		return nil, model.NewAppError("createDirectChannelWithUser", "api.channel.create_channel.direct_channel.remote_restricted.app_error", nil, "", http.StatusForbidden)
 	}
 
@@ -528,9 +528,11 @@ func (a *App) createGroupChannel(c request.CTX, userIDs []string) (*model.Channe
 		return nil, model.NewAppError("CreateGroupChannel", "api.channel.create_group.bad_user.app_error", nil, "user_ids="+model.ArrayToJSON(userIDs), http.StatusBadRequest)
 	}
 
-	for _, user := range users {
-		if user.IsRemote() {
-			return nil, model.NewAppError("createGroupChannel", "api.channel.create_group.remote_restricted.app_error", nil, "", http.StatusForbidden)
+	if !a.Config().FeatureFlags.EnableSharedChannelsDMs {
+		for _, user := range users {
+			if user.IsRemote() {
+				return nil, model.NewAppError("createGroupChannel", "api.channel.create_group.remote_restricted.app_error", nil, "", http.StatusForbidden)
+			}
 		}
 	}
 

server/channels/app/post.go

@@ -141,7 +141,7 @@ func (a *App) deduplicateCreatePost(rctx request.CTX, post *model.Post) (foundPo
 }
 
 func (a *App) CreatePost(c request.CTX, post *model.Post, channel *model.Channel, flags model.CreatePostFlags) (savedPost *model.Post, err *model.AppError) {
-	if channel.IsShared() && (channel.Type == model.ChannelTypeDirect || channel.Type == model.ChannelTypeGroup) {
+	if !a.Config().FeatureFlags.EnableSharedChannelsDMs && channel.IsShared() && (channel.Type == model.ChannelTypeDirect || channel.Type == model.ChannelTypeGroup) {
 		return nil, model.NewAppError("CreatePost", "app.post.create_post.shared_dm_or_gm.app_error", nil, "", http.StatusBadRequest)
 	}
 

server/platform/services/sharedchannel/service_api.go

@@ -22,7 +22,7 @@ func (scs *Service) ShareChannel(sc *model.SharedChannel) (*model.SharedChannel,
 		return nil, fmt.Errorf("cannot fetch channel while sharing channel %s: %w", sc.ChannelId, err)
 	}
 
-	if channel.Type == model.ChannelTypeDirect || channel.Type == model.ChannelTypeGroup {
+	if !scs.server.Config().FeatureFlags.EnableSharedChannelsDMs && (channel.Type == model.ChannelTypeDirect || channel.Type == model.ChannelTypeGroup) {
 		return nil, errors.New("cannot share a direct or group channel")
 	}
 

server/public/model/feature_flags.go

@@ -19,6 +19,9 @@ type FeatureFlags struct {
 	// Enable the remote cluster service for shared channels.
 	EnableRemoteClusterService bool
 
+	// Enable DMs and GMs for shared channels.
+	EnableSharedChannelsDMs bool
+
 	// AppsEnabled toggles the Apps framework functionalities both in server and client side
 	AppsEnabled bool
 
@@ -58,6 +61,7 @@ func (f *FeatureFlags) SetDefaults() {
 	f.TestFeature = "off"
 	f.TestBoolFeature = false
 	f.EnableRemoteClusterService = false
+	f.EnableSharedChannelsDMs = false
 	f.AppsEnabled = false
 	f.NormalizeLdapDNs = false
 	f.DeprecateCloudFree = false

webapp/channels/src/components/advanced_text_editor/advanced_text_editor.tsx

@@ -11,7 +11,7 @@ import type {ServerError} from '@mattermost/types/errors';
 import {savePreferences} from 'mattermost-redux/actions/preferences';
 import {Permissions} from 'mattermost-redux/constants';
 import {getChannel, makeGetChannel, getDirectChannel} from 'mattermost-redux/selectors/entities/channels';
-import {getConfig} from 'mattermost-redux/selectors/entities/general';
+import {getConfig, getFeatureFlagValue} from 'mattermost-redux/selectors/entities/general';
 import {get, getBool, getInt} from 'mattermost-redux/selectors/entities/preferences';
 import {haveIChannelPermission} from 'mattermost-redux/selectors/entities/roles';
 import {getCurrentUserId, isCurrentUserGuestUser, getStatusForUserId, makeGetDisplayName} from 'mattermost-redux/selectors/entities/users';
@@ -168,8 +168,9 @@ const AdvancedTextEditor = ({
 
     const readOnlyChannel = !canPost;
     const hasDraftMessage = Boolean(draft.message);
+    const enableSharedChannelsDMs = useSelector((state: GlobalState) => getFeatureFlagValue(state, 'EnableSharedChannelsDMs') === 'true');
     const isDMOrGMRemote = isChannelShared && (channelType === Constants.DM_CHANNEL || channelType === Constants.GM_CHANNEL);
-    const isDisabled = Boolean(readOnlyChannel || isDMOrGMRemote);
+    const isDisabled = Boolean(readOnlyChannel || (!enableSharedChannelsDMs && isDMOrGMRemote));
 
     const handleShowPreview = useCallback(() => {
         setShowPreview((prev) => !prev);
@@ -484,11 +485,11 @@ const AdvancedTextEditor = ({
                 defaultMessage: 'This channel is read-only. Only members with permission can post here.',
             },
         );
-    } else if (isDMOrGMRemote) {
+    } else if (!enableSharedChannelsDMs && isDMOrGMRemote) {
         createMessage = formatMessage(
             {
                 id: 'create_post.dm_or_gm_remote',
-                defaultMessage: 'Direct Messagess and Group Messages with remote users are not supported.',
+                defaultMessage: 'Direct Messages and Group Messages with remote users are not supported.',
             },
         );
     } else {

webapp/channels/src/i18n/en.json

@@ -3437,7 +3437,7 @@
   "create_group_memberships_modal.create": "Yes",
   "create_group_memberships_modal.desc": "You're about to add or re-add {username} to teams and channels based on their LDAP group membership. You can revert this change at any time.",
   "create_group_memberships_modal.title": "Re-add {username} to teams and channels",
-  "create_post.dm_or_gm_remote": "Direct Messagess and Group Messages with remote users are not supported.",
+  "create_post.dm_or_gm_remote": "Direct Messages and Group Messages with remote users are not supported.",
   "create_post.error_message": "Your message is too long. Character count: {length}/{limit}",
   "create_post.file_limit_sticky_banner.admin_message": "New uploads will automatically archive older files. To view them again, you can delete older files or <a>upgrade to a paid plan.</a>",
   "create_post.file_limit_sticky_banner.messageTitle": "Your free plan is limited to {storageGB} of files.",