[MM-69688] Fix /share-channel status always showing "--" for Last Sync (#37345)

* [MM-69688] Fix /share-channel status Last Sync always showing --

GetRemotesStatus never selected the sync cursor columns, so
SharedChannelRemoteStatus.NextSyncAt was always the zero value and
formatTimestamp rendered "--". Select GREATEST of the LastPostUpdateAt
and LastMembersSyncAt cursors as LastSyncAt and render that field.

Co-authored-by: mattermost-code <matty-code@mattermost.com>

* [MM-69688] Cover LastSyncAt in GetRemotesStatus store test

Advance the post and members sync cursors and assert GetRemotesStatus
reports LastSyncAt as the greater of the two, and reports zero when a
remote has never synced.

Co-authored-by: mattermost-code <matty-code@mattermost.com>

* [MM-69688] Add command and formatTimestamp coverage for Last Sync

Add doStatus command-layer tests asserting the /share-channel status
output renders a timestamp for a synced remote and "--" for an
unsynced one, a formatTimestamp unit test for the zero/today/older
branches, and harden the store test so both GREATEST operands are
non-zero.

Co-authored-by: mattermost-code <matty-code@mattermost.com>

* [MM-69688] Assert the non-today timestamp format in formatTimestamp test

Co-authored-by: mattermost-code <matty-code@mattermost.com>

* Trigger CI re-run after transient Postgres shard 3 Docker Hub failure

Co-authored-by: mattermost-code <matty-code@mattermost.com>

* [MM-69688] Include LastPostCreateAt in Last Sync computation

---------

Co-authored-by: Cursor Agent <cursoragent@cursor.com>
Co-authored-by: mattermost-code <matty-code@mattermost.com>

server/channels/app/slashcommands/command_share.go

@@ -301,7 +301,7 @@ func (sp *ShareProvider) doStatus(a *app.App, args *model.CommandArgs, _ map[str
 		accepted := formatBool(args.T, status.IsInviteAccepted)
 		online := formatBool(args.T, isOnline(status.LastPingAt))
 
-		lastSync := formatTimestamp(status.NextSyncAt)
+		lastSync := formatTimestamp(status.LastSyncAt)
 
 		fmt.Fprintf(&sb, "| %s | %s | %s | %s | %s | %s |\n",
 			status.DisplayName, status.SiteURL, readonly, accepted, online, lastSync)

server/channels/app/slashcommands/command_share_test.go

@@ -127,6 +127,87 @@ func TestShareProviderDoCommand(t *testing.T) {
 	})
 }
 
+func TestShareProviderDoStatus(t *testing.T) {
+	seedInvitedRemote := func(t *testing.T, th *TestHelper, channelID string) *model.SharedChannelRemote {
+		t.Helper()
+		rc, err := th.App.AddRemoteCluster(&model.RemoteCluster{
+			RemoteId:    model.NewId(),
+			Name:        "remote-" + model.NewId(),
+			DisplayName: "Remote Status Display",
+			SiteURL:     "https://remote-status.example.com",
+			Token:       model.NewId(),
+			Topics:      "topic",
+			CreateAt:    model.GetMillis(),
+			LastPingAt:  model.GetMillis(),
+			CreatorId:   model.NewId(),
+		})
+		require.Nil(t, err)
+
+		scr, saveErr := th.App.SaveSharedChannelRemote(&model.SharedChannelRemote{
+			Id:                model.NewId(),
+			ChannelId:         channelID,
+			RemoteId:          rc.RemoteId,
+			CreatorId:         th.BasicUser.Id,
+			IsInviteAccepted:  true,
+			IsInviteConfirmed: true,
+		})
+		require.NoError(t, saveErr)
+		return scr
+	}
+
+	statusArgs := func(th *TestHelper, channelID string) *model.CommandArgs {
+		return &model.CommandArgs{
+			T:         func(s string, args ...any) string { return s },
+			ChannelId: channelID,
+			UserId:    th.BasicUser.Id,
+			TeamId:    th.BasicTeam.Id,
+			Command:   "/share-channel status",
+		}
+	}
+
+	t.Run("renders the last sync timestamp for a remote that has synced", func(t *testing.T) {
+		th := setupForSharedChannels(t).initBasic(t)
+		th.addPermissionToRole(t, model.PermissionManageSharedChannels.Id, th.BasicUser.Roles)
+
+		mockSyncService := app.NewMockSharedChannelService(th.Server.GetSharedChannelSyncService())
+		th.Server.SetSharedChannelSyncService(mockSyncService)
+
+		channel := th.CreateChannel(t, th.BasicTeam, WithShared(true))
+		scr := seedInvitedRemote(t, th, channel.Id)
+
+		syncAt := model.GetMillis() - 5000
+		require.NoError(t, th.App.Srv().Store().SharedChannel().UpdateRemoteCursor(scr.Id, model.GetPostsSinceForSyncCursor{
+			LastPostUpdateAt: syncAt,
+			LastPostUpdateID: model.NewId(),
+		}))
+
+		commandProvider := ShareProvider{}
+		response := commandProvider.DoCommand(th.App, th.Context, statusArgs(th, channel.Id), "")
+
+		require.Contains(t, response.Text, "Remote Status Display")
+		assert.Contains(t, response.Text, "Today ", "expected a rendered timestamp in the Last Sync column, got:\n%s", response.Text)
+		assert.NotContains(t, response.Text, "| -- |", "Last Sync column should not be the placeholder for a synced remote:\n%s", response.Text)
+	})
+
+	t.Run("renders a placeholder when the remote has never synced", func(t *testing.T) {
+		th := setupForSharedChannels(t).initBasic(t)
+		th.addPermissionToRole(t, model.PermissionManageSharedChannels.Id, th.BasicUser.Roles)
+
+		mockSyncService := app.NewMockSharedChannelService(th.Server.GetSharedChannelSyncService())
+		th.Server.SetSharedChannelSyncService(mockSyncService)
+
+		channel := th.CreateChannel(t, th.BasicTeam, WithShared(true))
+		seedInvitedRemote(t, th, channel.Id)
+
+		commandProvider := ShareProvider{}
+		response := commandProvider.DoCommand(th.App, th.Context, statusArgs(th, channel.Id), "")
+
+		require.Contains(t, response.Text, "Remote Status Display")
+		assert.Contains(t, response.Text, "| -- |", "expected the Last Sync placeholder for an unsynced remote, got:\n%s", response.Text)
+		assert.NotContains(t, response.Text, "Today ", "unsynced remote should not render a timestamp:\n%s", response.Text)
+	})
+}
+
 func TestShareProviderGetAutoCompleteListItemsPermission(t *testing.T) {
 	connectionIDArg := func() *model.AutocompleteArg {
 		return &model.AutocompleteArg{Name: "connectionID"}

server/channels/app/slashcommands/util_test.go

@@ -4,9 +4,13 @@
 package slashcommands
 
 import (
+	"strings"
 	"testing"
+	"time"
 
 	"github.com/stretchr/testify/assert"
+
+	"github.com/mattermost/mattermost/server/public/model"
 )
 
 func TestParseNamedArgs(t *testing.T) {
@@ -38,3 +42,22 @@ func TestParseNamedArgs(t *testing.T) {
 		assert.Equal(t, tt.m, m, tt.name)
 	}
 }
+
+func TestFormatTimestamp(t *testing.T) {
+	t.Run("zero renders as placeholder", func(t *testing.T) {
+		assert.Equal(t, "--", formatTimestamp(0))
+	})
+
+	t.Run("today renders with a Today prefix", func(t *testing.T) {
+		got := formatTimestamp(model.GetMillis())
+		assert.True(t, strings.HasPrefix(got, "Today "), "expected a Today prefix, got %q", got)
+	})
+
+	t.Run("an earlier day renders the full date without the placeholder", func(t *testing.T) {
+		twoDaysAgo := model.GetMillis() - int64(48*time.Hour/time.Millisecond)
+		got := formatTimestamp(twoDaysAgo)
+		assert.NotEqual(t, "--", got)
+		assert.False(t, strings.HasPrefix(got, "Today "), "expected a full date, got %q", got)
+		assert.Equal(t, model.GetTimeForMillis(twoDaysAgo).Format("Jan 2 15:04:05 MST 2006"), got)
+	})
+}

server/channels/store/sqlstore/shared_channel_store.go

@@ -679,7 +679,7 @@ func (s SqlSharedChannelStore) GetRemotesStatus(channelId string) ([]*model.Shar
 	status := []*model.SharedChannelRemoteStatus{}
 
 	query := s.getQueryBuilder().
-		Select("scr.ChannelId, scr.RemoteId, rc.DisplayName, rc.SiteURL, rc.LastPingAt, sc.ReadOnly, scr.IsInviteAccepted").
+		Select("scr.ChannelId, scr.RemoteId, rc.DisplayName, rc.SiteURL, rc.LastPingAt, sc.ReadOnly, scr.IsInviteAccepted, GREATEST(COALESCE(scr.LastPostCreateAt, 0), COALESCE(scr.LastPostUpdateAt, 0), COALESCE(scr.LastMembersSyncAt, 0)) AS LastSyncAt").
 		From("SharedChannelRemotes scr, RemoteClusters rc, SharedChannels sc").
 		Where("scr.RemoteId = rc.RemoteId").
 		Where("scr.DeleteAt = 0").

server/channels/store/storetest/shared_channel_store.go

@@ -815,6 +815,37 @@ func testGetRemotesStatus(t *testing.T, rctx request.CTX, ss store.Store) {
 	_, err = ss.SharedChannel().SaveRemote(scr2)
 	require.NoError(t, err)
 
+	// Advance the sync cursors so the reported LastSyncAt reflects real activity.
+	// scr1's members sync is newer than its post sync, so LastSyncAt must track the
+	// members cursor. scr2's post-create cursor is the newest of all three cursors,
+	// so LastSyncAt must track it. The post-create cursor advances independently of
+	// the post-update cursor (see GetPostsSinceForSync), so it can be the most recent
+	// sync activity and must be one of the GREATEST operands.
+	now := model.GetMillis()
+	scr1PostSyncAt := now - 5000
+	scr1MembersSyncAt := now - 1000
+	scr2PostCreateAt := now - 500
+	scr2PostUpdateAt := now - 3000
+	scr2MembersSyncAt := now - 7000
+
+	err = ss.SharedChannel().UpdateRemoteCursor(scr1.Id, model.GetPostsSinceForSyncCursor{
+		LastPostUpdateAt: scr1PostSyncAt,
+		LastPostUpdateID: model.NewId(),
+	})
+	require.NoError(t, err)
+	err = ss.SharedChannel().UpdateRemoteMembershipCursor(scr1.Id, scr1MembersSyncAt)
+	require.NoError(t, err)
+
+	err = ss.SharedChannel().UpdateRemoteCursor(scr2.Id, model.GetPostsSinceForSyncCursor{
+		LastPostCreateAt: scr2PostCreateAt,
+		LastPostCreateID: model.NewId(),
+		LastPostUpdateAt: scr2PostUpdateAt,
+		LastPostUpdateID: model.NewId(),
+	})
+	require.NoError(t, err)
+	err = ss.SharedChannel().UpdateRemoteMembershipCursor(scr2.Id, scr2MembersSyncAt)
+	require.NoError(t, err)
+
 	t.Run("Get remotes status for channel", func(t *testing.T) {
 		statuses, err := ss.SharedChannel().GetRemotesStatus(channel.Id)
 		require.NoError(t, err)
@@ -833,6 +864,8 @@ func testGetRemotesStatus(t *testing.T, rctx request.CTX, ss store.Store) {
 		assert.Equal(t, rc1.DisplayName, s1.DisplayName)
 		assert.Equal(t, rc1.SiteURL, s1.SiteURL)
 		assert.True(t, s1.IsInviteAccepted)
+		// LastSyncAt is the greater of the post and members cursors.
+		assert.Equal(t, scr1MembersSyncAt, s1.LastSyncAt)
 
 		s2 := statusMap[rc2.RemoteId]
 		require.NotNil(t, s2)
@@ -841,6 +874,34 @@ func testGetRemotesStatus(t *testing.T, rctx request.CTX, ss store.Store) {
 		assert.Equal(t, rc2.DisplayName, s2.DisplayName)
 		assert.Equal(t, rc2.SiteURL, s2.SiteURL)
 		assert.False(t, s2.IsInviteAccepted)
+		// The post-create cursor is the newest cursor, so LastSyncAt tracks it. If the
+		// post-create cursor were excluded from GREATEST, this would report the older
+		// post-update cursor instead.
+		assert.Equal(t, scr2PostCreateAt, s2.LastSyncAt)
+	})
+
+	t.Run("Reports zero last sync when the remote has never synced", func(t *testing.T) {
+		unsyncedChannel, err := createTestChannel(ss, rctx, "test_remotes_status_unsynced")
+		require.NoError(t, err)
+
+		_, scErr := shareChannel(ss, unsyncedChannel, true, "")
+		require.NoError(t, scErr)
+
+		scrUnsynced := &model.SharedChannelRemote{
+			Id:                model.NewId(),
+			ChannelId:         unsyncedChannel.Id,
+			RemoteId:          rc1.RemoteId,
+			CreatorId:         rc1.CreatorId,
+			IsInviteAccepted:  true,
+			IsInviteConfirmed: true,
+		}
+		_, err = ss.SharedChannel().SaveRemote(scrUnsynced)
+		require.NoError(t, err)
+
+		statuses, err := ss.SharedChannel().GetRemotesStatus(unsyncedChannel.Id)
+		require.NoError(t, err)
+		require.Len(t, statuses, 1)
+		assert.Zero(t, statuses[0].LastSyncAt)
 	})
 
 	t.Run("Get remotes status for channel with no remotes", func(t *testing.T) {

server/public/model/shared_channel.go

@@ -167,7 +167,7 @@ type SharedChannelRemoteStatus struct {
 	DisplayName      string `json:"display_name"`
 	SiteURL          string `json:"site_url"`
 	LastPingAt       int64  `json:"last_ping_at"`
-	NextSyncAt       int64  `json:"next_sync_at"`
+	LastSyncAt       int64  `json:"last_sync_at"`
 	ReadOnly         bool   `json:"readonly"`
 	IsInviteAccepted bool   `json:"is_invite_accepted"`
 	Token            string `json:"token"`