Ignore unread counts in non-opened topics.

Telegram/SourceFiles/data/data_forum_topic.cpp

@@ -153,6 +153,9 @@ ForumTopic::ForumTopic(not_null<Forum*> forum, MsgId rootId)
 	_sendActionPainter->setTopic(this);
 
 	_replies->unreadCountValue(
+	) | rpl::map([=](std::optional<int> value) {
+		return value ? _replies->displayedUnreadCount() : value;
+	}) | rpl::distinct_until_changed(
 	) | rpl::combine_previous(
 	) | rpl::filter([=] {
 		return inChatList();
@@ -620,7 +623,7 @@ not_null<HistoryView::SendActionPainter*> ForumTopic::sendActionPainter() {
 
 Dialogs::UnreadState ForumTopic::chatListUnreadState() const {
 	return unreadStateFor(
-		_replies->unreadCountCurrent(),
+		_replies->displayedUnreadCount(),
 		_replies->unreadCountKnown());
 }
 

Telegram/SourceFiles/data/data_replies_list.cpp

@@ -765,6 +765,10 @@ void RepliesList::setUnreadCount(std::optional<int> count) {
 	}
 }
 
+int RepliesList::displayedUnreadCount() const {
+	return (_inboxReadTillId > 1) ? unreadCountCurrent() : 0;
+}
+
 bool RepliesList::isServerSideUnread(
 		not_null<const HistoryItem*> item) const {
 	const auto till = item->out()
@@ -847,7 +851,7 @@ void RepliesList::requestUnreadCount() {
 	const auto session = &_history->session();
 	const auto fullId = FullMsgId(_history->peer->id, _rootId);
 	const auto apply = [weak, session, fullId](
-			int readTill,
+			MsgId readTill,
 			int unreadCount) {
 		if (const auto strong = weak.get()) {
 			strong->setInboxReadTill(readTill, unreadCount);

Telegram/SourceFiles/data/data_replies_list.h

@@ -34,6 +34,7 @@ public:
 
 	[[nodiscard]] bool unreadCountKnown() const;
 	[[nodiscard]] int unreadCountCurrent() const;
+	[[nodiscard]] int displayedUnreadCount() const;
 	[[nodiscard]] rpl::producer<std::optional<int>> unreadCountValue() const;
 
 	void setInboxReadTill(MsgId readTillId, std::optional<int> unreadCount);

Telegram/SourceFiles/history/view/history_view_replies_section.cpp

@@ -1202,9 +1202,7 @@ void RepliesWidget::refreshJoinGroupButton() {
 		}
 	};
 	const auto channel = _history->peer->asChannel();
-	if (channel->amIn()
-		|| !channel->joinToWrite()
-		|| (channel->amCreator() && channel->canWrite())) {
+	if (channel->amIn() || channel->canWrite()) {
 		set(nullptr);
 	} else {
 		if (!_joinGroup) {

Telegram/SourceFiles/window/window_session_controller.cpp

@@ -42,6 +42,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_forum.h"
 #include "data/data_forum_topic.h"
 #include "data/data_chat_filters.h"
+#include "data/data_replies_list.h"
 #include "data/data_peer_values.h"
 #include "passport/passport_form_controller.h"
 #include "chat_helpers/tabbed_selector.h"
@@ -470,6 +471,18 @@ void SessionNavigation::showRepliesForMessage(
 		MsgId rootId,
 		MsgId commentId,
 		const SectionShow &params) {
+	if (const auto topic = history->peer->forumTopicFor(rootId)) {
+		auto replies = topic->replies();
+		if (replies->unreadCountKnown()) {
+			auto memento = std::make_shared<HistoryView::RepliesMemento>(
+				history,
+				rootId,
+				commentId);
+			memento->setReplies(std::move(replies));
+			showSection(std::move(memento), params);
+			return;
+		}
+	}
 	if (_showingRepliesRequestId
 		&& _showingRepliesHistory == history.get()
 		&& _showingRepliesRootId == rootId) {
@@ -530,9 +543,14 @@ void SessionNavigation::showRepliesForMessage(
 				}
 			}
 			if (deleted || item) {
-				auto memento = std::make_shared<HistoryView::RepliesMemento>(
-					item,
-					commentId);
+				auto memento = item
+					? std::make_shared<HistoryView::RepliesMemento>(
+						item,
+						commentId)
+					: std::make_shared<HistoryView::RepliesMemento>(
+						history,
+						rootId,
+						commentId);
 				memento->setReadInformation(
 					data.vread_inbox_max_id().value_or_empty(),
 					data.vunread_count().v,