gateway: outbound might core if connection lost during QM "restart"

Before: outbound might core if the following is true
* There is a connection lost.
* QM is "absent" (has been online before, but is restarting)
* outbound has advertised at least one queue for the connection
* No other connection has the same queue

Now: We detect the error that QM is "absent" and just discard sending
the _unadvertise_ message (to the non existing QM)

Resolves #199

middleware/gateway/include/gateway/group/tcp.h

@@ -159,7 +159,7 @@ namespace casual
             common::algorithm::container::trim( m_connections, common::algorithm::remove( m_connections, descriptor));
 
             auto found = common::algorithm::find( m_information, descriptor);
-            casual::assertion( descriptor, "fail to find information for descriptor: ", descriptor);
+            casual::assertion( found, "fail to find information for descriptor: ", descriptor);
 
             return common::algorithm::container::extract( m_information, std::begin( found));
          }
@@ -259,7 +259,19 @@ namespace casual
 
                // we 'lost' the connection in some way - we put a connection::Lost on our own ipc-device, and handle it
                // later (and differently depending on if we're 'regular' or 'reversed')
-               common::communication::ipc::inbound::device().push( lost( state, descriptor));
+               //
+               // NOTE: lost functor might throw, and we have noexcept. If we fail to execute lost and handle the lost connection
+               // properly there's no point in going on, we have a broken state in some way. We still catch and log the
+               // error to help find potential future errors in lost (it should not throw).
+               // TODO: Make sure lost is noexcept (compile time) and force the responsibility to "where it belongs"?
+               try
+               {
+                  common::communication::ipc::inbound::device().push( lost( state, descriptor));
+               }
+               catch( ...)
+               {
+                  casual::terminate( "failed to handle lost connection for descriptor: ", descriptor, " - error: ", exception::capture());
+               }
             }
          }
       } // detail::handle::communication

middleware/gateway/source/group/outbound/handle.cpp

@@ -969,7 +969,13 @@ namespace casual
          {
             casual::queue::ipc::message::Advertise request{ common::process::handle()};
             request.queues.remove = std::move( resources.queues);
-            state.multiplex.send( ipc::manager::optional::queue(), request);
+            // this throws if queue-manager is absent.
+            // TODO send on instance::optional::Device should not throw?
+            common::exception::guard( [ &]()
+            {
+               state.multiplex.send( ipc::manager::optional::queue(), request);
+            });
+
          }
       }