From 2868899d814e80679ac44aa08977b73b0f236692 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Wed, 3 Jan 2018 12:06:02 +0300
Subject: [PATCH] Fix possible assertion violation.

Allow removing local HistoryItem's after the album was already sent.
---
 Telegram/SourceFiles/apiwrap.cpp    | 10 +++++++++-
 Telegram/SourceFiles/app.cpp        | 28 ++++++++++++++++----------
 Telegram/SourceFiles/mainwidget.cpp | 31 +++++++++++++++++------------
 3 files changed, 44 insertions(+), 25 deletions(-)

diff --git a/Telegram/SourceFiles/apiwrap.cpp b/Telegram/SourceFiles/apiwrap.cpp
index 070ef68dd1..0933395f34 100644
--- a/Telegram/SourceFiles/apiwrap.cpp
+++ b/Telegram/SourceFiles/apiwrap.cpp
@@ -2960,7 +2960,15 @@ void ApiWrap::sendAlbumWithCancelled(
 		const MessageGroupId &groupId) {
 	const auto localId = item->fullId();
 	const auto albumIt = _sendingAlbums.find(groupId.raw());
-	Assert(albumIt != _sendingAlbums.end());
+	if (albumIt != _sendingAlbums.end()) {
+		// Sometimes we destroy item being sent already after the album
+		// was sent successfully. For example the message could be loaded
+		// from server (by messages.getHistory or updateNewMessage) and
+		// added to history and after that updateMessageID was received with
+		// the same message id, in this case we destroy a detached local
+		// item and sendAlbumWithCancelled is called for already sent album.
+		return;
+	}
 	const auto &album = albumIt->second;
 
 	const auto proj = [](const SendingAlbum::Item &item) {
diff --git a/Telegram/SourceFiles/app.cpp b/Telegram/SourceFiles/app.cpp
index bd97e7d5e0..b6d93ff5b3 100644
--- a/Telegram/SourceFiles/app.cpp
+++ b/Telegram/SourceFiles/app.cpp
@@ -1061,29 +1061,35 @@ namespace {
 	}
 
 	void feedWereDeleted(ChannelId channelId, const QVector<MTPint> &msgsIds) {
-		MsgsData *data = fetchMsgsData(channelId, false);
+		const auto data = fetchMsgsData(channelId, false);
 		if (!data) return;
 
-		ChannelHistory *channelHistory = (channelId == NoChannel) ? 0 : App::historyLoaded(peerFromChannel(channelId))->asChannelHistory();
+		const auto channelHistory = (channelId != NoChannel)
+			? App::history(peerFromChannel(channelId))->asChannelHistory()
+			: nullptr;
 
-		QMap<History*, bool> historiesToCheck;
-		for (QVector<MTPint>::const_iterator i = msgsIds.cbegin(), e = msgsIds.cend(); i != e; ++i) {
-			MsgsData::const_iterator j = data->constFind(i->v);
+		base::flat_set<not_null<History*>> historiesToCheck;
+		for (const auto msgId : msgsIds) {
+			auto j = data->constFind(msgId.v);
 			if (j != data->cend()) {
-				History *h = (*j)->history();
+				const auto h = (*j)->history();
 				(*j)->destroy();
-				if (!h->lastMsg) historiesToCheck.insert(h, true);
+				if (!h->lastMsg) {
+					historiesToCheck.emplace(h);
+				}
 			} else {
 				if (channelHistory) {
-					if (channelHistory->unreadCount() > 0 && i->v >= channelHistory->inboxReadBefore) {
-						channelHistory->setUnreadCount(channelHistory->unreadCount() - 1);
+					if (channelHistory->unreadCount() > 0
+						&& msgId.v >= channelHistory->inboxReadBefore) {
+						channelHistory->setUnreadCount(
+							channelHistory->unreadCount() - 1);
 					}
 				}
 			}
 		}
 		if (main()) {
-			for (QMap<History*, bool>::const_iterator i = historiesToCheck.cbegin(), e = historiesToCheck.cend(); i != e; ++i) {
-				main()->checkPeerHistory(i.key()->peer);
+			for (const auto history : historiesToCheck) {
+				main()->checkPeerHistory(history->peer);
 			}
 		}
 	}
diff --git a/Telegram/SourceFiles/mainwidget.cpp b/Telegram/SourceFiles/mainwidget.cpp
index 77c470993b..7a69bfd879 100644
--- a/Telegram/SourceFiles/mainwidget.cpp
+++ b/Telegram/SourceFiles/mainwidget.cpp
@@ -4925,24 +4925,29 @@ void MainWidget::feedUpdate(const MTPUpdate &update) {
 	} break;
 
 	case mtpc_updateMessageID: {
-		auto &d = update.c_updateMessageID();
-		auto msg = App::histItemByRandom(d.vrandom_id.v);
-		if (msg.msg) {
-			if (auto msgRow = App::histItemById(msg)) {
-				if (App::histItemById(msg.channel, d.vid.v)) {
-					auto history = msgRow->history();
-					auto wasLast = (history->lastMsg == msgRow);
-					msgRow->destroy();
+		const auto &d = update.c_updateMessageID();
+		if (const auto fullId = App::histItemByRandom(d.vrandom_id.v)) {
+			const auto channel = fullId.channel;
+			const auto newId = d.vid.v;
+			if (const auto local = App::histItemById(fullId)) {
+				const auto existing = App::histItemById(channel, newId);
+				if (existing && local->detached()) {
+					const auto history = local->history();
+					const auto wasLast = (history->lastMsg == local);
+					local->destroy();
 					if (wasLast && !history->lastMsg) {
 						checkPeerHistory(history->peer);
 					}
 					_history->peerMessagesUpdated();
 				} else {
-					App::historyUnregItem(msgRow);
-					Auth().messageIdChanging.notify({ msgRow, d.vid.v }, true);
-					msgRow->setId(d.vid.v);
-					App::historyRegItem(msgRow);
-					Auth().data().requestItemRepaint(msgRow);
+					if (existing) {
+						existing->destroy();
+					}
+					App::historyUnregItem(local);
+					Auth().messageIdChanging.notify({ local, newId }, true);
+					local->setId(d.vid.v);
+					App::historyRegItem(local);
+					Auth().data().requestItemRepaint(local);
 				}
 			}
 			App::historyUnregRandom(d.vrandom_id.v);