From d57aa2a1f6580d4b7b7af0938e8414df996b532c Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Thu, 25 May 2023 11:50:06 +0400
Subject: [PATCH] Fix possible crash on MTP::Instance shutdown.

---
 Telegram/SourceFiles/mtproto/session.cpp | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/Telegram/SourceFiles/mtproto/session.cpp b/Telegram/SourceFiles/mtproto/session.cpp
index a10f2e7d57..0a50a45614 100644
--- a/Telegram/SourceFiles/mtproto/session.cpp
+++ b/Telegram/SourceFiles/mtproto/session.cpp
@@ -557,13 +557,22 @@ void Session::tryToReceive() {
 		if (messages.empty()) {
 			break;
 		}
+		const auto guard = QPointer<Session>(this);
+		const auto instance = QPointer<Instance>(_instance);
+		const auto main = (_shiftedDcId == BareDcId(_shiftedDcId));
 		for (const auto &message : messages) {
 			if (message.requestId) {
-				_instance->processCallback(message);
-			} else if (_shiftedDcId == BareDcId(_shiftedDcId)) {
+				instance->processCallback(message);
+			} else if (main) {
 				// Process updates only in main session.
-				_instance->processUpdate(message);
+				instance->processUpdate(message);
 			}
+			if (!instance) {
+				return;
+			}
+		}
+		if (!guard) {
+			break;
 		}
 	}
 }