mesecons/mesecons_detector/init.lua:70: bad argument #2 to 'set_string' (string expected, got table)

[Bastrabun]

Upstream issue mesecons:

Repro:

Have mesecons, digilines

1. Place mesecons_luacontroller:luacontroller
2. Place mesecons_detector:object_detector
3. Add channel "kaputt" to object_detector
4. Add code to luacontroller: digiline_send("kaputt",{})
5. Press Execute

Crash

AsyncErr: Lua: Runtime error from mod 'mesecons' in callback environment_Step(): ...est-temp/bin/../mods/mesecons/mesecons_detector/init.lua:70: bad argument #2 to 'set_string' (string expected, got table)
stack traceback:
	[C]: in function 'set_string'
	...est-temp/bin/../mods/mesecons/mesecons_detector/init.lua:70: in function 'action'
	.../5.10.0/minetest-temp/bin/../mods/digilines/internal.lua:106: in function 'transmit'
	...test/5.10.0/minetest-temp/bin/../mods/digilines/init.lua:60: in function 'receptor_send'
	...emp/bin/../mods/mesecons/mesecons_luacontroller/init.lua:752: in function <...emp/bin/../mods/mesecons/mesecons_luacontroller/init.lua:746>
	...etest-temp/bin/../mods/mesecons/mesecons/actionqueue.lua:131: in function 'execute'
	...etest-temp/bin/../mods/mesecons/mesecons/actionqueue.lua:121: in function <...etest-temp/bin/../mods/mesecons/mesecons/actionqueue.lua:76>
	.../5.10.0/minetest-temp/bin/../builtin/common/register.lua:26: in function <.../5.10.0/minetest-temp/bin/../builtin/common/register.lua:12>

This doesn't happen in 5.8.0, only in 5.9.1 and 5.10.0 and 5.11.0-dev

The difference is in handling of incorrect arguments in case of meta:set_string("key", {}) - it silently unsets the key on 5.8 and errors on 5.9+

Please add a type check

Similar minetest-mods/MoreMesecons#38

For my reference 7743

[SmallJoker]

Does this fix your issue as intended? I took digistuff/gpu.lua as a reference where the type is checked in the same way.

diff --git a/mesecons_detector/init.lua b/mesecons_detector/init.lua
index a8d0300..2653174 100644
--- a/mesecons_detector/init.lua
+++ b/mesecons_detector/init.lua
@@ -66,7 +66,8 @@ local object_detector_digiline = {
        effector = {
                action = function(pos, _, channel, msg)
                        local meta = minetest.get_meta(pos)
-                       if channel == meta:get_string("digiline_channel") then
+                       if channel == meta:get_string("digiline_channel") and
+                                       (type(msg) == "string" or type(msg) == "number") then
                                meta:set_string("scanname", msg)
                                object_detector_make_formspec(pos)
                        end

[cheapie]

That looks like it would work (haven't tried it yet) but it should probably only check for strings as numbers aren't valid values.

[SmallJoker]

5c82089