Add userdata-wrappers feature

This feature allow to opt into `impl UserData` for `Rc<T>`/`Arc<T>`/`Rc<RefCell<T>>`/`Arc<Mutex<T>>` where `T: UserData`
Close #470

Author: khvzak

.github/workflows/main.yml

@@ -27,8 +27,8 @@ jobs:
       - name: Build ${{ matrix.lua }} vendored
         run: |
           cargo build --features "${{ matrix.lua }},vendored"
-          cargo build --features "${{ matrix.lua }},vendored,async,serialize,macros,anyhow"
-          cargo build --features "${{ matrix.lua }},vendored,async,serialize,macros,anyhow,send"
+          cargo build --features "${{ matrix.lua }},vendored,async,serialize,macros,anyhow,userdata-wrappers"
+          cargo build --features "${{ matrix.lua }},vendored,async,serialize,macros,anyhow,userdata-wrappers,send"
         shell: bash
       - name: Build ${{ matrix.lua }} pkg-config
         if: ${{ matrix.os == 'ubuntu-latest' }}
@@ -51,7 +51,7 @@ jobs:
           toolchain: stable
           target: aarch64-apple-darwin
       - name: Cross-compile
-        run: cargo build --target aarch64-apple-darwin --features "${{ matrix.lua }},vendored,async,send,serialize,macros"
+        run: cargo build --target aarch64-apple-darwin --features "${{ matrix.lua }},vendored,async,send,serialize,macros,anyhow,userdata-wrappers"
 
   build_aarch64_cross_ubuntu:
     name: Cross-compile to aarch64-unknown-linux-gnu
@@ -72,7 +72,7 @@ jobs:
           sudo apt-get install -y --no-install-recommends gcc-aarch64-linux-gnu libc6-dev-arm64-cross
         shell: bash
       - name: Cross-compile
-        run: cargo build --target aarch64-unknown-linux-gnu --features "${{ matrix.lua }},vendored,async,send,serialize,macros"
+        run: cargo build --target aarch64-unknown-linux-gnu --features "${{ matrix.lua }},vendored,async,send,serialize,macros,anyhow,userdata-wrappers"
         shell: bash
 
   build_armv7_cross_ubuntu:
@@ -94,7 +94,7 @@ jobs:
           sudo apt-get install -y --no-install-recommends gcc-arm-linux-gnueabihf libc-dev-armhf-cross
         shell: bash
       - name: Cross-compile
-        run: cargo build --target armv7-unknown-linux-gnueabihf --features "${{ matrix.lua }},vendored,async,send,serialize,macros"
+        run: cargo build --target armv7-unknown-linux-gnueabihf --features "${{ matrix.lua }},vendored,async,send,serialize,macros,anyhow,userdata-wrappers"
         shell: bash
 
   test:
@@ -123,8 +123,8 @@ jobs:
       - name: Run ${{ matrix.lua }} tests
         run: |
           cargo test --features "${{ matrix.lua }},vendored"
-          cargo test --features "${{ matrix.lua }},vendored,async,serialize,macros,anyhow"
-          cargo test --features "${{ matrix.lua }},vendored,async,serialize,macros,anyhow,send"
+          cargo test --features "${{ matrix.lua }},vendored,async,serialize,macros,anyhow,userdata-wrappers"
+          cargo test --features "${{ matrix.lua }},vendored,async,serialize,macros,anyhow,userdata-wrappers,send"
         shell: bash
       - name: Run compile tests (macos lua54)
         if: ${{ matrix.os == 'macos-latest' && matrix.lua == 'lua54' }}
@@ -154,8 +154,8 @@ jobs:
       - uses: Swatinem/rust-cache@v2
       - name: Run ${{ matrix.lua }} tests with address sanitizer
         run: |
-          cargo test --tests --features "${{ matrix.lua }},vendored,async,serialize,macros" --target x86_64-unknown-linux-gnu -- --skip test_too_many_recursions
-          cargo test --tests --features "${{ matrix.lua }},vendored,async,serialize,macros,send" --target x86_64-unknown-linux-gnu -- --skip test_too_many_recursions
+          cargo test --tests --features "${{ matrix.lua }},vendored,async,serialize,macros,anyhow" --target x86_64-unknown-linux-gnu -- --skip test_too_many_recursions
+          cargo test --tests --features "${{ matrix.lua }},vendored,async,serialize,macros,anyhow,userdata-wrappers,send" --target x86_64-unknown-linux-gnu -- --skip test_too_many_recursions
         shell: bash
         env:
           RUSTFLAGS: -Z sanitizer=address
@@ -181,7 +181,7 @@ jobs:
       - uses: Swatinem/rust-cache@v2
       - name: Run ${{ matrix.lua }} tests with forced memory limit
         run: |
-          cargo test --tests --features "${{ matrix.lua }},vendored,async,send,serialize,macros"
+          cargo test --tests --features "${{ matrix.lua }},vendored,async,send,serialize,macros,anyhow,userdata-wrappers"
         shell: bash
         env:
           RUSTFLAGS: --cfg=force_memory_limit
@@ -254,7 +254,7 @@ jobs:
       - name: Run ${{ matrix.lua }} tests
         run: |
           cargo test --tests --features "${{ matrix.lua }},vendored"
-          cargo test --tests --features "${{ matrix.lua }},vendored,async,serialize,macros"
+          cargo test --tests --features "${{ matrix.lua }},vendored,async,serialize,macros,anyhow,userdata-wrappers"
 
   rustfmt:
     name: Rustfmt
@@ -281,4 +281,4 @@ jobs:
       - uses: giraffate/clippy-action@v1
         with:
           reporter: 'github-pr-review'
-          clippy_flags: --features "${{ matrix.lua }},vendored,async,send,serialize,macros,anyhow"
+          clippy_flags: --features "${{ matrix.lua }},vendored,async,send,serialize,macros,anyhow,userdata-wrappers"

Cargo.toml

@@ -43,6 +43,7 @@ error-send = []
 serialize = ["dep:serde", "dep:erased-serde", "dep:serde-value"]
 macros = ["mlua_derive/macros"]
 anyhow = ["dep:anyhow", "error-send"]
+userdata-wrappers = []
 
 [dependencies]
 mlua_derive = { version = "=0.10.0", optional = true, path = "mlua_derive" }

README.md

@@ -57,6 +57,7 @@ Below is a list of the available feature flags. By default `mlua` does not enabl
 * `serialize`: add serialization and deserialization support to `mlua` types using [serde] framework
 * `macros`: enable procedural macros (such as `chunk!`)
 * `anyhow`: enable `anyhow::Error` conversion into Lua
+* `userdata-wrappers`: opt into `impl UserData` for `Rc<T>`/`Arc<T>`/`Rc<RefCell<T>>`/`Arc<Mutex<T>>` where `T: UserData`
 
 [5.4]: https://www.lua.org/manual/5.4/manual.html
 [5.3]: https://www.lua.org/manual/5.3/manual.html

src/scope.rs

@@ -1,7 +1,6 @@
 use std::cell::RefCell;
 use std::marker::PhantomData;
 use std::mem;
-use std::os::raw::c_void;
 
 use crate::error::{Error, Result};
 use crate::function::Function;
@@ -183,7 +182,7 @@ impl<'scope, 'env: 'scope> Scope<'scope, 'env> {
             let ud_ptr = util::push_uninit_userdata::<UserDataStorage<T>>(state, protect)?;
 
             // Push the metatable and register it with no TypeId
-            let mut registry = UserDataRegistry::new_unique(ud_ptr as *const c_void);
+            let mut registry = UserDataRegistry::new_unique(ud_ptr as *mut _);
             T::register(&mut registry);
             self.lua.push_userdata_metatable(registry)?;
             let mt_ptr = ffi::lua_topointer(state, -1);