clear alert nofify function when calling abort on a session, to avoid touching a destructed session object (#1015)

include/libtorrent/session.hpp

@@ -281,7 +281,7 @@ namespace libtorrent
 		// 		session_proxy();
 		// 		~session_proxy()
 		// 	};
-		session_proxy abort() { return session_proxy(m_io_service, m_thread, m_impl); }
+		session_proxy abort();
 
 	private:
 

simulation/test_checking.cpp

@@ -69,7 +69,6 @@ void run_test(Setup const& setup, Test const& test)
 		test(*ses);
 
 		// shut down
-		ses->set_alert_notify([]{});
 		zombie = ses->abort();
 		ses.reset();
 	});

simulation/test_fast_extensions.cpp

@@ -79,7 +79,6 @@ void run_fake_peer_test(
 	sim::timer t(sim, lt::seconds(1)
 		, [&](boost::system::error_code const& ec)
 	{
-		ses->set_alert_notify([]{});
 		// shut down
 		zombie = ses->abort();
 

simulation/test_ip_filter.cpp

@@ -88,7 +88,6 @@ void run_test(Setup const& setup
 	{
 		test(*ses, test_peers);
 
-		ses->set_alert_notify([]{});
 		// shut down
 		zombie = ses->abort();
 

simulation/test_optimistic_unchoke.cpp

@@ -148,7 +148,6 @@ TORRENT_TEST(optimistic_unchoke)
 		{
 			p->abort();
 		}
-		ses->set_alert_notify([]{});
 		proxy = ses->abort();
 		ses.reset();
 	});

simulation/test_socks5.cpp

@@ -101,7 +101,6 @@ void run_test(Setup const& setup
 	{
 		fprintf(stderr, "shutting down\n");
 		// shut down
-		ses->set_alert_notify([] {});
 		zombie = ses->abort();
 		ses.reset();
 	});

simulation/test_tracker.cpp

@@ -352,7 +352,6 @@ TORRENT_TEST(ipv6_support)
 			, [&ses,&zombie](boost::system::error_code const& ec)
 		{
 			zombie = ses->abort();
-			ses->set_alert_notify([]{});
 			ses.reset();
 		});
 
@@ -427,7 +426,6 @@ void tracker_test(Setup setup, Announce a, Test1 test1, Test2 test2
 		, [&ses,&zombie](boost::system::error_code const& ec)
 	{
 		zombie = ses->abort();
-		ses->set_alert_notify([]{});
 		ses.reset();
 	});
 

simulation/test_transfer.cpp

@@ -139,7 +139,6 @@ void run_test(
 		int idx = 0;
 		for (auto& s : ses)
 		{
-			s->set_alert_notify([]{});
 			zombie[idx++] = s->abort();
 			s.reset();
 		}

simulation/test_web_seed.cpp

@@ -113,7 +113,6 @@ void run_test(Setup const& setup
 	{
 		fprintf(stderr, "shutting down\n");
 		// shut down
-		ses->set_alert_notify([] {});
 		zombie = ses->abort();
 		ses.reset();
 	});

src/session.cpp

@@ -409,6 +409,14 @@ namespace libtorrent
 			m_thread->join();
 	}
 
+	session_proxy session::abort()
+	{
+		// stop calling the alert notify function now, to avoid it thinking the
+		// session is still alive
+		m_impl->alerts().set_notify_function(boost::function<void()>());
+		return session_proxy(m_io_service, m_thread, m_impl);
+	}
+
 #ifndef TORRENT_NO_DEPRECATE
 	session_settings::session_settings(std::string const& user_agent_)
 	{

src/session_impl.cpp

@@ -1076,6 +1076,10 @@ namespace aux {
 		session_log(" *** ABORT CALLED ***");
 #endif
 
+		// at this point we cannot call the notify function anymore, since the
+		// session will become invalid.
+		m_alerts.set_notify_function(boost::function<void()>());
+
 		// this will cancel requests that are not critical for shutting down
 		// cleanly. i.e. essentially tracker hostname lookups that we're not
 		// about to send event=stopped to