Ideas & Concerns

[Tired-Fox]

This project is early and experimental. Please share any ideas or concerns here.

[ian-h-chamberlain]

Hi, not sure if this is still under development but it looks like it a very interesting project! I wanted to try it out but I can't seem to get the example to compile on main or develop branches...

$ cargo check --features vendored
   Compiling mlua-sys v0.6.3
error: You can enable only one of the features: lua54, lua53, lua52, lua51, luajit, luajit52, luau
  --> /Users/ianchamberlain/.config/cargo/registry/src/index.crates.io-1949cf8c6b5b557f/mlua-sys-0.6.3/build/main.rs:16:13
   |
16 |             compile_error!("You can enable only one of the features: lua54, lua53, lua52, lua51, luajit, luajit52, luau");
   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: could not compile `mlua-sys` (build script) due to 1 previous error

Any idea what I'm missing here? Is there some other combination of feature flags I should be using? I'll try to set up the right environment for lua54 or something meanwhile but just asking to make sure I'm not missing something obvious.

[ian-h-chamberlain]

Update: lua54 seems to be working after setting up my environemnt, although I'm not sure why vendored didn't.

Now I'm running into another set of errors while trying to use the send feature; it appears to fail on all the helper wrapper methods for a missing Send bound, which seems odd because I was able to compile the examples just fine! I don't even have to add any code before trying this to see it fail:

error[E0277]: the trait bound `SET: mlua::types::MaybeSend` is not satisfied
   --> /Users/ianchamberlain/Documents/Development/mlua-extras/src/extras/mod.rs:399:43
    |
399 |         self.add_field_function_set(name, set);
    |              ----------------------       ^^^ the trait `Send` is not implemented for `SET`
    |              |
    |              required by a bound introduced by this call
    |
    = note: required for `SET` to implement `mlua::types::MaybeSend`
note: required by a bound in `add_field_function_set`
   --> /Users/ianchamberlain/.config/cargo/registry/src/index.crates.io-1949cf8c6b5b557f/mlua-0.9.9/src/userdata.rs:534:67
    |
532 |     fn add_field_function_set<F, A>(&mut self, name: impl AsRef<str>, function: F)
    |        ---------------------- required by a bound in this associated function
533 |     where
534 |         F: FnMut(&'lua Lua, AnyUserData<'lua>, A) -> Result<()> + MaybeSend + 'static,
    |                                                                   ^^^^^^^^^ required by this bound in `UserDataFields::add_field_function_set`
help: use parentheses to call this type parameter
    |
399 |         self.add_field_function_set(name, set(/* &'lua Lua */, /* AnyUserData<'lua> */, /* A */));
    |                                              +++++++++++++++++++++++++++++++++++++++++++++++++++
help: consider further restricting type parameter `SET` with trait `Send`
    |
396 |         SET: 'static + MaybeSend + Fn(&'lua Lua, AnyUserData<'lua>, A) -> mlua::Result<()> + std::marker::Send,
    |                                                                                            +++++++++++++++++++

For more information about this error, try `rustc --explain E0277`.
error: could not compile `mlua-extras` (lib) due to 35 previous errors

Any ideas about what might be going on here or if there's a way to resolve it?

[Tired-Fox]

@ian-h-chamberlain

For the vendored feature flag, it follows mlua's feature flag scheme so you will have to specify a lua version like so ["vendored", "lua54"].

For the error above, it looks like the mlua "send" feature is enabled. This will make it so that the MaybeSend trait will require anything that implements it to also implement Send. The fix for this would be to either remove the "send" feature from mlua or add the "send" feature to this crate in your Cargo.toml.

[StayBlue]

Hello! I stumbled upon this crate, and the automatic generation of documentation is something that'd be really useful for my project. Will the mlua version be updated?

[Tired-Fox]

@StayBlue

Yes. I can look at bumping the version this week if you are still interested