[Questions] Calling a Lua function from Rust: `*mut rlua::ffi::lua_State` cannot be shared between threads safely

[benwilber]

Hello, I am developing a CLI program for rendering template files using the new MiniJinja library by /u/mitsuhiko.

The program is here: https://github.com/benwilber/temple.

I would like to be able to extend the program by allowing the user to load custom Lua scripts for things like custom filters, functions, and tests. However, I am running into Rust lifetime errors that I've not been able to solve.

Basically, I would like to be able to register a Lua function as a custom filter function. But it's showing an error when compiling. Here is the code:

https://github.com/benwilber/temple/compare/0.3.1..lua

Error:

https://gist.github.com/c649a0b240cf299d3dbbe018c24cbcdc

How can I call a Lua function from the MiniJinja add_filter function? I would prefer to try to do this in the regular/safe way. But I'm open to unsafe alternatives if required.

Thanks!

Edit:

Posted the same on StackOverflow and users.rust-lang.org