degesch: Lua: avoid resource leak

If a connector's on_success callback fails, we need to destroy the connection.

degesch.c

@@ -8091,12 +8091,9 @@ struct lua_connection
 	int socket_fd;                      ///< Underlying connected socket
 };
 
-static int
+static void
-lua_connection_close (lua_State *L)
+lua_connection_discard (struct lua_connection *self)
 {
-	struct lua_connection *self =
-		luaL_checkudata (L, 1, XLUA_CONNECTION_METATABLE);
-
 	if (self->socket_fd != -1)
 	{
 		poller_fd_reset (&self->socket_event);
@@ -8105,7 +8102,13 @@ lua_connection_close (lua_State *L)
 	}
 
 	// Connection is dead, we don't need to hold onto any resources anymore
-	lua_cache_invalidate (L, self);
+	lua_cache_invalidate (self->plugin->L, self);
+}
+
+static int
+lua_connection_close (lua_State *L)
+{
+	lua_connection_discard (luaL_checkudata (L, 1, XLUA_CONNECTION_METATABLE));
 	return 0;
 }
 
@@ -8187,9 +8190,7 @@ lua_connector_discard (struct lua_connector *self)
 static int
 lua_connector_abort (lua_State *L)
 {
-	struct lua_connector *self =
+	lua_connector_discard (luaL_checkudata (L, 1, XLUA_CONNECTOR_METATABLE));
-		luaL_checkudata (L, 1, XLUA_CONNECTOR_METATABLE);
-	lua_connector_discard (self);
 	return 0;
 }
 
@@ -8214,11 +8215,16 @@ lua_connector_on_connected (void *user_data, int socket, const char *hostname)
 	{
 		lua_State *L = self->plugin->L;
 		lua_rawgeti (L, LUA_REGISTRYINDEX, self->ref_on_success);
-		lua_plugin_push_connection (self->plugin, socket);  // 1: connection
+		struct lua_connection *connection =
+			lua_plugin_push_connection (self->plugin, socket);  // 1: connection
 
 		struct error *e = NULL;
 		if (!lua_plugin_call (self->plugin, 1, 0, &e))
+		{
 			lua_plugin_log_error (self->plugin, "connector on_success", e);
+			// The connection has placed itself in the cache
+			lua_connection_discard (connection);
+		}
 	}
 
 	lua_connector_discard (self);