fix(channels): sync stop replaying clear-history updates

internal/app/channels/service.go

@@ -2302,14 +2302,6 @@ func (s *Service) GetDifference(ctx context.Context, userID int64, req domain.Ch
 		return domain.ChannelDifference{}, err
 	}
 	diff = s.filterBotChannelDifference(ctx, userID, diff)
-	if diff.Self.HistoryClearAnchorID > 0 &&
-		diff.Self.HistoryClearAnchorID == diff.Self.AvailableMinID &&
-		!diff.TooLong {
-		// updateChannelAvailableMessages is an absolute no-PTS update. Keep it
-		// outside ChannelUpdateEvent so channel difference continuity remains
-		// defined solely by real channel events.
-		diff.AvailableMinID = diff.Self.AvailableMinID
-	}
 	return diff, nil
 }
 

internal/domain/channel.go

@@ -1335,10 +1335,6 @@ type ChannelDifference struct {
 	Events       []ChannelUpdateEvent
 	NewMessages  []ChannelMessage
 	OtherUpdates []ChannelUpdateEvent
-	// AvailableMinID is an owner-local, absolute no-PTS boundary appended to a
-	// normal channel difference. It must never be represented as a synthetic
-	// ChannelUpdateEvent because updateChannelAvailableMessages has no pts.
-	AvailableMinID int
 	Users        []User
 	Channels     []Channel
 	Pts          int

internal/rpc/channels_messages_rpc_test.go

@@ -273,6 +273,7 @@ func TestChannelsDeleteHistoryLocalClearEmitsAvailableMessagesUpdate(t *testing.
 		t.Fatalf("offline account state = %+v, want unchanged pts=%d and non-regressing date", offlineDiff.State, stateBefore.Pts)
 	}
 
+	for attempt := 1; attempt <= 2; attempt++ {
 		channelOffline, err := r.onUpdatesGetChannelDifference(WithUserID(ctx, owner.ID), &tg.UpdatesGetChannelDifferenceRequest{
 			Channel: &tg.InputChannel{ChannelID: channel.ID, AccessHash: channel.AccessHash},
 			Filter:  &tg.ChannelMessagesFilterEmpty{},
@@ -280,25 +281,13 @@ func TestChannelsDeleteHistoryLocalClearEmitsAvailableMessagesUpdate(t *testing.
 			Limit:   100,
 		})
 		if err != nil {
-		t.Fatalf("channel difference after offline local clear: %v", err)
+			t.Fatalf("channel difference attempt %d after offline local clear: %v", attempt, err)
 		}
-	channelDiff, ok := channelOffline.(*tg.UpdatesChannelDifference)
+		channelDiff, ok := channelOffline.(*tg.UpdatesChannelDifferenceEmpty)
-	if !ok {
+		if !ok || channelDiff.Pts != newChannelUpdate.Pts {
-		t.Fatalf("offline channel difference = %T %+v, want non-empty difference with absolute update", channelOffline, channelOffline)
+			t.Fatalf("channel difference attempt %d = %T %+v, want empty with unchanged channel pts=%d",
+				attempt, channelOffline, channelOffline, newChannelUpdate.Pts)
 		}
-	var channelAvailable *tg.UpdateChannelAvailableMessages
-	for _, update := range channelDiff.OtherUpdates {
-		if value, ok := update.(*tg.UpdateChannelAvailableMessages); ok {
-			channelAvailable = value
-			break
-		}
-	}
-	if channelAvailable == nil ||
-		channelAvailable.ChannelID != channel.ID ||
-		channelAvailable.AvailableMinID != msg.ID ||
-		channelDiff.Pts != newChannelUpdate.Pts {
-		t.Fatalf("offline channel updates = %+v pts=%d, want available boundary %d with unchanged channel pts=%d",
-			channelDiff.OtherUpdates, channelDiff.Pts, msg.ID, newChannelUpdate.Pts)
 	}
 
 	req := &tg.MessagesGetDialogsRequest{OffsetPeer: &tg.InputPeerEmpty{}, Limit: 20}

internal/rpc/convert_updates.go

@@ -122,7 +122,7 @@ func tgChannelDifference(viewerUserID int64, diff domain.ChannelDifference) tg.U
 			Users:    tgUsersForViewer(viewerUserID, diff.Users),
 		}
 	}
-	if len(diff.Events) == 0 && len(diff.NewMessages) == 0 && len(diff.OtherUpdates) == 0 && diff.AvailableMinID == 0 {
+	if len(diff.Events) == 0 && len(diff.NewMessages) == 0 && len(diff.OtherUpdates) == 0 {
 		return &tg.UpdatesChannelDifferenceEmpty{
 			Final:   diff.Final,
 			Pts:     diff.Pts,
@@ -148,12 +148,6 @@ func tgChannelDifference(viewerUserID int64, diff domain.ChannelDifference) tg.U
 			updates = append(updates, update)
 		}
 	}
-	if diff.AvailableMinID > 0 {
-		updates = append(updates, &tg.UpdateChannelAvailableMessages{
-			ChannelID:      diff.Channel.ID,
-			AvailableMinID: diff.AvailableMinID,
-		})
-	}
 	chats := tgChannelDifferenceChats(viewerUserID, diff)
 	users := tgUsersForViewer(viewerUserID, diff.Users)
 	return &tg.UpdatesChannelDifference{