From adf738854ae214f2c41e3199ccbbbe810df22ccd Mon Sep 17 00:00:00 2001
From: Nils Dagsson Moskopp <nils@dieweltistgarnichtso.net>
Date: Wed, 26 Jan 2022 17:37:55 +0100
Subject: [PATCH] Fix mob-in-boat crash in Minetest 5.5-dev
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
In Minetest 5.4.1, calling get_player_control() on a mob returned the
empty string. Minetest commit 5eb45e1ea03c6104f007efec6dd9c351f310193d
changed this, so now calling get_player_control() on a mob returns nil.
As mcl_boats defines boats that can have a player or a mob as a driver,
code like the following crashes with a changed get_player_control() API:
local ctrl = driver:get_player_control()
if ctrl.sneak then
detach_object(driver, true)
end
Furthermore, once a world has crashed, joining it near a mob that is the
driver of a boat with such control code immediately crashes again.
When I reported this bug to Minetest, several Minetest core developers
stated that they disliked the old API and proposed other return values
for calling a mob's get_player_control() function – all different from
the empty string. Since I have some doubts that this bug will be fixed
in Minetest 5.5.0, boat code must take into account a nil return value.
Minetest issue: https://github.com/minetest/minetest/issues/11989
---
mods/ENTITIES/mcl_boats/init.lua | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/mods/ENTITIES/mcl_boats/init.lua b/mods/ENTITIES/mcl_boats/init.lua
index beff5fb52..72664b1df 100644
--- a/mods/ENTITIES/mcl_boats/init.lua
+++ b/mods/ENTITIES/mcl_boats/init.lua
@@ -267,7 +267,7 @@ function boat.on_step(self, dtime, moveresult)
return
end
local yaw = self.object:get_yaw()
- if ctrl.up then
+ if ctrl and ctrl.up then
-- Forwards
self._v = self._v + 0.1 * v_factor
@@ -276,7 +276,7 @@ function boat.on_step(self, dtime, moveresult)
self.object:set_animation({x=0, y=40}, paddling_speed, 0, true)
self._animation = 1
end
- elseif ctrl.down then
+ elseif ctrl and ctrl.down then
-- Backwards
self._v = self._v - 0.1 * v_factor