Fix updating unread message reactions.

Telegram/SourceFiles/data/data_message_reactions.cpp

@@ -517,6 +517,60 @@ void MessageReactions::remove() {
 	add(QString());
 }
 
+bool MessageReactions::checkIfChanged(
+		const QVector<MTPReactionCount> &list,
+		const QVector<MTPMessagePeerReaction> &recent) const {
+	auto &owner = _item->history()->owner();
+	if (owner.reactions().sending(_item)) {
+		// We'll apply non-stale data from the request response.
+		return false;
+	}
+	auto existing = base::flat_set<QString>();
+	for (const auto &count : list) {
+		const auto changed = count.match([&](const MTPDreactionCount &data) {
+			const auto reaction = qs(data.vreaction());
+			const auto nowCount = data.vcount().v;
+			const auto i = _list.find(reaction);
+			const auto wasCount = (i != end(_list)) ? i->second : 0;
+			if (wasCount != nowCount) {
+				return true;
+			}
+			existing.emplace(reaction);
+			return false;
+		});
+		if (changed) {
+			return true;
+		}
+	}
+	for (const auto &[reaction, count] : _list) {
+		if (!existing.contains(reaction)) {
+			return true;
+		}
+	}
+	auto parsed = base::flat_map<QString, std::vector<RecentReaction>>();
+	for (const auto &reaction : recent) {
+		reaction.match([&](const MTPDmessagePeerReaction &data) {
+			const auto emoji = qs(data.vreaction());
+			if (_list.contains(emoji)) {
+				parsed[emoji].push_back(RecentReaction{
+					.peer = owner.peer(peerFromMTP(data.vpeer_id())),
+					.unread = data.is_unread(),
+					.big = data.is_big(),
+				});
+			}
+		});
+	}
+	return !ranges::equal(_recent, parsed, [](
+			const auto &a,
+			const auto &b) {
+		return ranges::equal(a.second, b.second, [](
+				const RecentReaction &a,
+				const RecentReaction &b) {
+			return (a.peer == b.peer) && (a.big == b.big);
+		});
+	});
+}
+
 void MessageReactions::set(
 		const QVector<MTPReactionCount> &list,
 		const QVector<MTPMessagePeerReaction> &recent,
@@ -531,10 +585,13 @@ void MessageReactions::set(
 	for (const auto &count : list) {
 		count.match([&](const MTPDreactionCount &data) {
 			const auto reaction = qs(data.vreaction());
-			if (data.is_chosen() && !ignoreChosen) {
-				if (_chosen != reaction) {
+			if (!ignoreChosen) {
+				if (data.is_chosen() && _chosen != reaction) {
 					_chosen = reaction;
 					changed = true;
+				} else if (!data.is_chosen() && _chosen == reaction) {
+					_chosen = QString();
+					changed = true;
 				}
 			}
 			const auto nowCount = data.vcount().v;

Telegram/SourceFiles/data/data_message_reactions.h

@@ -149,6 +149,9 @@ public:
 		const QVector<MTPReactionCount> &list,
 		const QVector<MTPMessagePeerReaction> &recent,
 		bool ignoreChosen);
+	[[nodiscard]] bool checkIfChanged(
+		const QVector<MTPReactionCount> &list,
+		const QVector<MTPMessagePeerReaction> &recent) const;
 	[[nodiscard]] const base::flat_map<QString, int> &list() const;
 	[[nodiscard]] auto recent() const
 		-> const base::flat_map<QString, std::vector<RecentReaction>> &;

Telegram/SourceFiles/history/history_item.cpp

@@ -850,12 +850,8 @@ void HistoryItem::updateReactions(const MTPMessageReactions *reactions) {
 	const auto toContact = toUser && toUser->isContact();
 	const auto hadUnread = hasUnreadReaction();
 	setReactions(reactions);
-	const auto unreadReaction = _reactions
-		? _reactions->findUnread()
-		: QString();
-	const auto hasUnread = !unreadReaction.isEmpty();
+	const auto hasUnread = hasUnreadReaction();
 	if (hasUnread && !hadUnread) {
-		_flags |= MessageFlag::HasUnreadReaction;
 		addToUnreadThings(HistoryUnreadThings::AddType::New);
 		if (toContact) {
 			const auto notification = ItemNotification{
@@ -894,16 +890,29 @@ void HistoryItem::setReactions(const MTPMessageReactions *reactions) {
 		if (data.vresults().v.isEmpty()) {
 			if (_reactions) {
 				_reactions = nullptr;
+				if (hasUnreadReaction()) {
+					markReactionsRead();
+				}
 				history()->owner().notifyItemDataChange(this);
 			}
 			return;
 		} else if (!_reactions) {
 			_reactions = std::make_unique<Data::MessageReactions>(this);
 		}
-		_reactions->set(
-			data.vresults().v,
-			data.vrecent_reactions().value_or_empty(),
-			data.is_min());
+		const auto min = data.is_min();
+		const auto &list = data.vresults().v;
+		const auto &recent = data.vrecent_reactions().value_or_empty();
+		if (min && hasUnreadReaction()) {
+			// We can't update reactions from min if we have unread.
+			if (_reactions->checkIfChanged(list, recent)) {
+				updateReactionsUnknown();
+			}
+		} else {
+			_reactions->set(list, recent, min);
+			if (!_reactions->findUnread().isEmpty()) {
+				_flags |= MessageFlag::HasUnreadReaction;
+			}
+		}
 	});
 }