Compilation errors with Lua 5.4.7

[noncom]

Getting some compilation errors when using latest Lua 5.4.7, like:

...
love\src\modules\graphics\wrap_Mesh.cpp(294,18): error C3861: 'luaL_checkint': identifier not found
...
love\src\modules\graphics\wrap_Graphics.cpp(1298,28): error C3861: 'luaL_checkint': identifier not found 
...
love\src\modules\image\wrap_ImageData.cpp(166,11): error C3861: 'luaL_optint': identifier not found
...

There's quite a number of them, these are just some examples, but all of then are in the wrap_*.cpp files.

I think that the explanation can be found in the last point of section 8.3 – Changes in the API at https://www.lua.org/manual/5.3/manual.html. Long story short -- these macros are deprecated, and need to be replaced with different calls for Lua 5.3+. It would be great if Love2D would handle this to support the most rececnt Lua versions.

[MikuAuahDark]

If you can send a PR for it, we'll review it.

Note that our official distribution is compiled using LuaJIT, for compatibility and performance reasons.

[noncom]

Ok so I researched the situation a bit more, and discovered this: https://github.com/lua/lua/blob/v5.4/lauxlib.h#L282.

Adding

#define LUA_COMPAT_APIINTCASTS 1

enables the compatibility mode and fixes the compilation error.

This reveals another compilation error about lua_assert() not being found in function utf8esc() in lutf8lib.c. Probably it's another API change.

This one is fixed by adding

#include "llimits.h"

to the includes in the file.

And after that Love2D compiles well with Lua 5.4.7 (*).

So the conclusion I came to here is: I don't think that creating a meaningful PR for this is possible? It feels more like just some info for some "Compiling with Lua 5.4+" doc or something. Even having this ticket as a reference probably would do.

---

(*) -- For future reference, of course this required changing all Lua5.1-related paths and constants in the makefile, and then creating the project and building with the LuaJit off flag:

cmake -G "Visual Studio 17 2022" -A x64 -S . -B build -DLOVE_JIT=OFF
cmake --build build --target love/love --config Release

[slime73]

Adding luax_checkint and luax_optint wrapper functions to runtime.h which do return (int) luaL_check/optinteger(L, ...) and then switching existing luaL_checkint and luaL_optint calls to those would be a good change, if you want to make a PR.

[noncom]

Yes, it would be great to simplify usage of Love2D with any LuaVM of choice. I will do this PR soon.

Also, the CMakeFiles of Love2D and megasource have the Lua51 and MEGA_LUA51 constant names to refer to a non-LuaJIT Lua. I would propose changing them to just Lua and MEGA_LUA since all CMakeLists already have JIT-specific constants with "JIT" in their name, and the Lua version number isn't really relevant. That's what I did locally, and it worked fine.

Alternatively maybe PucLua and MEGA_PUCLUA if just "Lua" is too imprecise, but most often in other projects I saw just "LUA" and "LUAJIT" to differentiate between them.