luau VS luacheck

As far as I can tell, they aren't.

http://lua-users.org/wiki/SandBoxes

There is a lot of information there, but it doesn't handle resource exhaustion, execution time limits or give any guarantees. It does indicate that it's possible, and has a decent example of the most restrictive setup, which is a good start. But I would for example compare it with Luau's SECURITY.md.

From https://github.com/luau-lang/luau/blob/master/SECURITY.md:

> Luau provides a safe sandbox that scripts can not escape from, short of vulnerabilities in custom C functions exposed by the host. This includes the virtual machine and builtin libraries. Notably this currently does not include the work-in-progress native code generation facilities.

> Any source code can not result in memory safety errors or crashes during its compilation or execution. Violations of memory safety are considered vulnerabilities.

> Note that Luau does not provide termination guarantees - some code may exhaust CPU or RAM resources on the system during compilation or execution.

So, even luau will have trouble with untrusted code, but it specifies exactly what happens and so on. I think that's fair enough.

Alternatively, Luau is a well-supported Lua variant with type checking and performance improvements, aimed more towards being a sandboxed embedded scripting environment.

https://luau-lang.org/

If you need Lua but also type-safety, how about Luau [1] then?

[1] https://luau-lang.org/

I had the pleasure of working with Lua 5.1 back in the late noughties. For me it's replaced Tcl whenever I want something I can configure above a C library. At the time I used it I found it quite nice but I'll also not forget the hours I wasted tracking down nil table corruptions which could have easily been caught by a type checker.

I had some hope that Luau https://luau-lang.org or Teal https://github.com/teal-language/tl would make things better but with the following example

    function foo(x: number): string

Looking at other replies here, I can see I wasn't the only one who didn't realize there is Lua and Luau. Luau is an extension of Lua: https://luau-lang.org/

> Luau is syntactically backwards-compatible with Lua 5.1 (code that is valid Lua 5.1 is also valid Luau); however, we have extended the language with a set of syntactical features that make the language more familiar and ergonomic.

Lua is usually the embedded language of choice. If you are focused on security, you could check out the Roblox fork, Luau (https://github.com/Roblox/luau) where the creators took extra care to lock down the language on what scripts could do.

Luau - Lua variant by Roblox

On a side note, I've heard that they recently switched from Lua to Roblox's own fork of Lua, Luau.

https://www.youtube.com/results?search_query=luau+roblox&sp=...

Luau

https://github.com/Roblox/luau

Roblox wrote a superset of Roblox Lua which is way faster

https://luau-lang.org/ - some documentation, and examples https://create.roblox.com/docs - documentation, tutorials, and examples https://www.youtube.com/user/AlvinBLOX - tutorials https://www.youtube.com/@TheDevKing/videos - tutorials https://www.lua.org/manual/5.1/ - not specific to Roblox, but Lua reference manual https://www.codecademy.com/learn/learn-lua - Lua on Codecademy

Not directly related, but luacheck can also help with this.

Yeah. While you're at it, make a habit of running luacheck on your files as it helps catch a lot of these issues that can sneak in by mistake: https://github.com/mpeterv/luacheck

Using something like https://github.com/mpeterv/luacheck might be helpful too. Will check all the files in a directory and will let you know which one might be problematic.

I'm trying to setup luacheck (via null-ls) to run alongside sumneko-lua (via nvim-lspconfig).

Most of the time nothing is used. The thing is that iterating is so quick, that you find the problems really fast.

Although, I've been using luacheck https://github.com/mpeterv/luacheck. It is quite nice, but you have to write down the global variables by hand on the config file.

Check out luacheck. It can help spot typos or mistakes you've made and warn against anti-patterns. I'd honestly only look into setting it up locally because there's no benefit to putting it in a CI pipeline unless you have one for another reason IMO. This should be all the config you need:

Sadly the scenario that the successor feature is intended to alleviate has very much become reality. The creator of Luacheck (Peter Melnichenko) passed away a couple of years ago, and ever since then the GitHub repository has been in a state of limbo. Multiple unofficial forks have come and gone, but Peter's is still the first result on Google if you search "luacheck". It isn't even possible to change the README or pin an issue to get people's attention about the fork; to this day people are still posting issues to the old repo.

And Luacheck is "the" Lua static analysis tool that pretty much everyone uses, so it's a very significant issue.

https://github.com/mpeterv/luacheck/issues/198

You are probably right, but luacheck is well aware of which global variables are built-in and it has special comments, such as -- no global or --ignore in case you very want to overwrite them.

Calling your function self is as much bad practice as calling it print. Use luacheck to avoid such mistakes.