From b04c7efdf4b1f98e04c9233132acb350700926b6 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Mon, 17 Nov 2025 18:15:16 +0400
Subject: [PATCH] Fix last server message tracking in sublist/forum.

Fixes #30011.
---
 Telegram/SourceFiles/api/api_updates.cpp         | 10 +++++++++-
 Telegram/SourceFiles/data/data_forum_topic.cpp   | 10 ++++++++++
 Telegram/SourceFiles/data/data_forum_topic.h     |  1 +
 Telegram/SourceFiles/data/data_saved_sublist.cpp |  5 +++--
 Telegram/SourceFiles/data/data_saved_sublist.h   |  4 ++--
 Telegram/SourceFiles/history/history.cpp         |  2 +-
 6 files changed, 26 insertions(+), 6 deletions(-)

diff --git a/Telegram/SourceFiles/api/api_updates.cpp b/Telegram/SourceFiles/api/api_updates.cpp
index 4394d71414..56b2b333cb 100644
--- a/Telegram/SourceFiles/api/api_updates.cpp
+++ b/Telegram/SourceFiles/api/api_updates.cpp
@@ -30,6 +30,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/notify/data_notify_settings.h"
 #include "data/stickers/data_stickers.h"
 #include "data/data_saved_messages.h"
+#include "data/data_saved_sublist.h"
 #include "data/data_session.h"
 #include "data/data_user.h"
 #include "data/data_chat.h"
@@ -43,6 +44,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_histories.h"
 #include "data/data_folder.h"
 #include "data/data_forum.h"
+#include "data/data_forum_topic.h"
 #include "data/data_send_action.h"
 #include "data/data_stories.h"
 #include "data/data_message_reactions.h"
@@ -1701,7 +1703,13 @@ void Updates::feedUpdate(const MTPUpdate &update) {
 								local->history()->peer,
 								local->date());
 						}
-						local->setRealId(d.vid().v);
+						local->setRealId(newId);
+						if (const auto topic = local->topic()) {
+							topic->applyMaybeLast(local);
+						}
+						if (const auto sublist = local->savedSublist()) {
+							sublist->applyMaybeLast(local);
+						}
 					}
 				}
 			} else {
diff --git a/Telegram/SourceFiles/data/data_forum_topic.cpp b/Telegram/SourceFiles/data/data_forum_topic.cpp
index 1dfa893bf4..4c4280ed7e 100644
--- a/Telegram/SourceFiles/data/data_forum_topic.cpp
+++ b/Telegram/SourceFiles/data/data_forum_topic.cpp
@@ -836,6 +836,16 @@ void ForumTopic::applyColorId(int32 colorId) {
 	}
 }
 
+void ForumTopic::applyMaybeLast(not_null<HistoryItem*> item) {
+	if (!_lastServerMessage.value_or(nullptr)
+		|| (*_lastServerMessage)->id < item->id) {
+		setLastServerMessage(item);
+		resolveChatListMessageGroup();
+	} else {
+		growLastKnownServerMessageId(item->id);
+	}
+}
+
 void ForumTopic::applyItemAdded(not_null<HistoryItem*> item) {
 	if (item->isRegular()) {
 		setLastServerMessage(item);
diff --git a/Telegram/SourceFiles/data/data_forum_topic.h b/Telegram/SourceFiles/data/data_forum_topic.h
index 49e299f963..068fb343ab 100644
--- a/Telegram/SourceFiles/data/data_forum_topic.h
+++ b/Telegram/SourceFiles/data/data_forum_topic.h
@@ -160,6 +160,7 @@ public:
 	void applyCreator(PeerId creatorId);
 	void applyCreationDate(TimeId date);
 	void applyIsMy(bool my);
+	void applyMaybeLast(not_null<HistoryItem*> item);
 	void applyItemAdded(not_null<HistoryItem*> item);
 	void applyItemRemoved(MsgId id);
 	void maybeSetLastMessage(not_null<HistoryItem*> item);
diff --git a/Telegram/SourceFiles/data/data_saved_sublist.cpp b/Telegram/SourceFiles/data/data_saved_sublist.cpp
index 69473cdc83..bf6d050147 100644
--- a/Telegram/SourceFiles/data/data_saved_sublist.cpp
+++ b/Telegram/SourceFiles/data/data_saved_sublist.cpp
@@ -187,12 +187,13 @@ rpl::producer<> SavedSublist::destroyed() const {
 		) | rpl::to_empty);
 }
 
-void SavedSublist::applyMaybeLast(not_null<HistoryItem*> item, bool added) {
-	growLastKnownServerMessageId(item->id);
+void SavedSublist::applyMaybeLast(not_null<HistoryItem*> item) {
 	if (!_lastServerMessage.value_or(nullptr)
 		|| (*_lastServerMessage)->id < item->id) {
 		setLastServerMessage(item);
 		resolveChatListMessageGroup();
+	} else {
+		growLastKnownServerMessageId(item->id);
 	}
 }
 
diff --git a/Telegram/SourceFiles/data/data_saved_sublist.h b/Telegram/SourceFiles/data/data_saved_sublist.h
index cdcc2e28ee..92098c16e4 100644
--- a/Telegram/SourceFiles/data/data_saved_sublist.h
+++ b/Telegram/SourceFiles/data/data_saved_sublist.h
@@ -52,8 +52,7 @@ public:
 	[[nodiscard]] bool isHiddenAuthor() const;
 	[[nodiscard]] rpl::producer<> destroyed() const;
 
-	void growLastKnownServerMessageId(MsgId id);
-	void applyMaybeLast(not_null<HistoryItem*> item, bool added = false);
+	void applyMaybeLast(not_null<HistoryItem*> item);
 	void applyItemAdded(not_null<HistoryItem*> item);
 	void applyItemRemoved(MsgId id);
 
@@ -143,6 +142,7 @@ private:
 	void setChatListMessage(HistoryItem *item);
 	void allowChatListMessageResolve();
 	void resolveChatListMessageGroup();
+	void growLastKnownServerMessageId(MsgId id);
 
 	void changeUnreadCountByMessage(MsgId id, int delta);
 	void setUnreadCount(std::optional<int> count);
diff --git a/Telegram/SourceFiles/history/history.cpp b/Telegram/SourceFiles/history/history.cpp
index d8c12b0731..63393d2d49 100644
--- a/Telegram/SourceFiles/history/history.cpp
+++ b/Telegram/SourceFiles/history/history.cpp
@@ -752,7 +752,7 @@ not_null<HistoryItem*> History::addNewItem(
 	}
 
 	if (const auto sublist = item->savedSublist()) {
-		sublist->applyMaybeLast(item, unread);
+		sublist->applyMaybeLast(item);
 	}
 
 	return item;