active-connection: drop off the bus when the settings connection disappears

The active connection has an immutable connection property, but is
cleaned asynchronously by the manager after its settings connection is
done. Fine, let's remove it from the bus first though, so that we don't
hang there with a dangling object path.

src/nm-active-connection.c

@@ -156,6 +156,20 @@ _settings_connection_updated (NMSettingsConnection *connection,
 	 * settings-connection. */
 }
 
+static void
+_settings_connection_removed (NMSettingsConnection *connection,
+                              gpointer user_data)
+{
+	NMActiveConnection *self = user_data;
+
+	/* Our settings connection is about to drop off. The next active connection
+	 * cleanup is going to tear us down (at least until we grow the capability to
+	 * re-link; in that case we'd just clean the references to the old connection here).
+	 * Let's remove ourselves from the bus so that we're not exposed with a dangling
+	 * reference to the setting connection once it's gone. */
+	nm_exported_object_unexport (NM_EXPORTED_OBJECT (self));
+}
+
 static void
 _set_settings_connection (NMActiveConnection *self, NMSettingsConnection *connection)
 {
@@ -170,6 +184,7 @@ _set_settings_connection (NMActiveConnection *self, NMSettingsConnection *connec
 	if (connection) {
 		priv->settings_connection = g_object_ref (connection);
 		g_signal_connect (connection, NM_SETTINGS_CONNECTION_UPDATED_INTERNAL, (GCallback) _settings_connection_updated, self);
+		g_signal_connect (connection, NM_SETTINGS_CONNECTION_REMOVED, (GCallback) _settings_connection_removed, self);
 	}
 }
 

src/settings/nm-settings.c

@@ -1112,7 +1112,9 @@ claim_connection (NMSettings *self, NMSettingsConnection *connection)
 	openconnect_migrate_hack (NM_CONNECTION (connection));
 
 	g_object_ref (self);
-	g_signal_connect (connection, NM_SETTINGS_CONNECTION_REMOVED,
+	/* This one unexports the connection, it needs to run late to give the active
+	 * connection a chance to deal with its reference to this settings connection. */
+	g_signal_connect_after (connection, NM_SETTINGS_CONNECTION_REMOVED,
 	                        G_CALLBACK (connection_removed), self);
 	g_signal_connect (connection, NM_SETTINGS_CONNECTION_UPDATED_INTERNAL,
 	                  G_CALLBACK (connection_updated), self);