snapshot of https://github.com/mattermost/mattermost.git (master, 2026-09-16; blobs > 131072B omitted)

server/platform/services/sharedchannel/membership.go

@@ -0,0 +1,57 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package sharedchannel
+
+import (
+	"time"
+
+	"github.com/mattermost/mattermost/server/public/model"
+	"github.com/mattermost/mattermost/server/public/shared/mlog"
+)
+
+func (scs *Service) isChannelMemberSyncEnabled() bool {
+	return scs.server.GetRemoteClusterService() != nil
+}
+
+// NotifyMembershipChanged is called when users are added or removed from a shared channel.
+// It triggers a sync for the channel so that membership changes are picked up from
+// ChannelMemberHistory at sync time, following the same pattern as posts and reactions.
+// originRemoteID identifies the remote that initiated the change, so it can be skipped
+// during sync to prevent echo-back.
+func (scs *Service) NotifyMembershipChanged(channelID string, originRemoteID string) {
+	if !scs.isChannelMemberSyncEnabled() {
+		return
+	}
+	task := newSyncTask(channelID, "", "", nil, nil)
+	task.originRemoteID = originRemoteID
+	task.schedule = time.Now().Add(NotifyMinimumDelay)
+	scs.addTask(task)
+}
+
+// ForceMembershipSyncForRemote triggers a sync for all channels shared with the specified remote.
+// Called when a remote comes back online to catch up on any membership changes that occurred
+// while it was offline. The sync pipeline will read ChannelMemberHistory using the
+// LastMembersSyncAt cursor to detect both additions and removals.
+func (scs *Service) ForceMembershipSyncForRemote(rc *model.RemoteCluster) {
+	if !scs.isChannelMemberSyncEnabled() {
+		return
+	}
+
+	opts := model.SharedChannelRemoteFilterOpts{
+		RemoteId: rc.RemoteId,
+	}
+	scrs, err := scs.server.GetStore().SharedChannel().GetRemotes(0, 999999, opts)
+	if err != nil {
+		scs.server.Log().LogM(mlog.MlvlSharedChannelServiceError, "Failed to fetch shared channel remotes for membership sync",
+			mlog.String("remote", rc.DisplayName),
+			mlog.String("remote_id", rc.RemoteId),
+			mlog.Err(err),
+		)
+		return
+	}
+
+	for _, scr := range scrs {
+		scs.NotifyChannelChanged(scr.ChannelId)
+	}
+}