with panic = "abort", any failure in a userdata function or method crashes the process even if it wasn't a panic #628
Description
I don't know if this is a bug or a feature request to be honest. The minimal repro below fails at the unwrap in main if panic = "abort" is not specified. If panic = "abort", though, it panics inside the crate across the Lua C API rather than bubbling the Result up to my code. This means that even if I go out of the way to write functions that validate and never panic, I can't use panic = "abort" because of that unwanted conversion.
Maybe I'm being dumb, but at the very least this doesn't seem documented. In my case though (game dev, backend stuff, etc) I really don't like unwind because it causes so-called grey failures. Maybe a panic propagates to all threads eventually, but that might not be for a long time, and you've just got this period where half the process died but the other half is still going--potentially even the bits that report that all is well to monitoring! So I consider it best practice to always use abort.
Anyway:
use mlua::{Lua, UserData, UserDataMethods};
struct Data(i32);
impl UserData for Data {
fn add_methods<M: UserDataMethods<Self>>(methods: &mut M) {
methods.add_method_mut("test", |_, this, _: ()| {
return Result::<(), _>::Err(mlua::Error::runtime("Failed!"));
//this.0 = 1;
//Ok(())
});
}
}
fn main() {
let lua = Lua::new();
let mut data = Data(0);
lua.scope(|scope| {
let ud = scope.create_userdata_ref_mut(&mut data)?;
lua.globals().set("d", ud)?;
lua.load("d:test()").eval::<()>().unwrap();
Ok(())
})
.unwrap();
}