v0.9.7

Use `&str` instead of creating Lua string when serializing tuple variant and struct variant

CHANGELOG.md

@@ -1,3 +1,22 @@
+## v0.9.7
+
+- Implemented `IntoLua` for `RegistryKey`
+- Mark `__idiv` metamethod as available for luau
+- Added `Function::deep_clone()` method (Luau)
+- Added `SerializeOptions::detect_serde_json_arbitrary_precision` option
+- Added `Lua::create_buffer()` method (Luau)
+- Support serializing buffer type as a byte slice (Luau)
+- Perf: Implemented `push_into_stack`/`from_stack` for `Option<T>`
+- Added `Lua::create_ser_any_userdata()` method
+
+## v0.9.6
+
+- Added `to_pointer` function to `Function`/`Table`/`Thread`
+- Implemented `IntoLua` for `&Value`
+- Implemented `FromLua` for `RegistryKey`
+- Faster (~5%) table array traversal during serialization
+- Some performance improvements for bool/int types
+
 ## v0.9.5
 
 - Minimal Luau updated to 0.609

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "mlua"
-version = "0.9.5" # remember to update mlua_derive
+version = "0.9.7" # remember to update mlua_derive
 authors = ["Aleksandr Orlenko <zxteam@pm.me>", "kyren <catherine@kyju.org>"]
 rust-version = "1.71"
 edition = "2021"
@@ -32,14 +32,14 @@ lua52 = ["ffi/lua52"]
 lua51 = ["ffi/lua51"]
 luajit = ["ffi/luajit"]
 luajit52 = ["luajit", "ffi/luajit52"]
-luau = ["ffi/luau", "libloading"]
+luau = ["ffi/luau", "dep:libloading"]
 luau-jit = ["luau", "ffi/luau-codegen"]
 luau-vector4 = ["luau", "ffi/luau-vector4"]
 vendored = ["ffi/vendored"]
-module = ["mlua_derive", "ffi/module"]
-async = ["futures-util"]
+module = ["dep:mlua_derive", "ffi/module"]
+async = ["dep:futures-util"]
 send = []
-serialize = ["serde", "erased-serde", "serde-value"]
+serialize = ["dep:serde", "dep:erased-serde", "dep:serde-value"]
 macros = ["mlua_derive/macros"]
 unstable = []
 
@@ -63,18 +63,20 @@ libloading = { version = "0.8", optional = true }
 [dev-dependencies]
 trybuild = "1.0"
 futures = "0.3.5"
-hyper = { version = "0.14", features = ["client", "server"] }
-reqwest = { version = "0.11", features = ["json"] }
+hyper = { version = "1.2", features = ["full"] }
+hyper-util = { version = "0.1.3", features = ["full"] }
+http-body-util = "0.1.1"
+reqwest = { version = "0.12", features = ["json"] }
 tokio = { version = "1.0", features = ["macros", "rt", "time"] }
 serde = { version = "1.0", features = ["derive"] }
-serde_json = "1.0"
+serde_json = { version = "1.0", features = ["arbitrary_precision"] }
 maplit = "1.0"
 tempfile = "3"
 static_assertions = "1.0"
 
 [target.'cfg(not(target_arch = "wasm32"))'.dev-dependencies]
 criterion = { version = "0.5", features = ["async_tokio"] }
-rustyline = "13.0"
+rustyline = "14.0"
 tokio = { version = "1.0", features = ["full"] }
 
 [[bench]]

README.md

@@ -84,6 +84,20 @@ This works using Lua [coroutines](https://www.lua.org/manual/5.3/manual.html#2.6
 - [HTTP Server](examples/async_http_server.rs)
 - [TCP Server](examples/async_tcp_server.rs)
 
+
+**shell command examples**:
+```shell
+# async http client (hyper)
+cargo run --example async_http_client --features=lua54,async,macros
+
+# async http client (reqwest)
+cargo run --example async_http_reqwest --features=lua54,async,macros,serialize
+
+# async http server
+cargo run --example async_http_server --features=lua54,async,macros
+curl -v http://localhost:3000
+```
+
 ### Serialization (serde) support
 
 With `serialize` feature flag enabled, `mlua` allows you to serialize/deserialize any type that implements [`serde::Serialize`] and [`serde::Deserialize`] into/from [`mlua::Value`]. In addition `mlua` provides [`serde::Serialize`] trait implementation for it (including `UserData` support).
@@ -119,7 +133,7 @@ Add to `Cargo.toml` :
 
 ``` toml
 [dependencies]
-mlua = { version = "0.9.1", features = ["lua54", "vendored"] }
+mlua = { version = "0.9.7", features = ["lua54", "vendored"] }
 ```
 
 `main.rs`
@@ -154,7 +168,7 @@ Add to `Cargo.toml` :
 crate-type = ["cdylib"]
 
 [dependencies]
-mlua = { version = "0.9.1", features = ["lua54", "module"] }
+mlua = { version = "0.9.7", features = ["lua54", "module"] }
 ```
 
 `lib.rs` :

benches/benchmark.rs

@@ -1,5 +1,7 @@
-use criterion::{criterion_group, criterion_main, BatchSize, Criterion};
+use std::sync::atomic::{AtomicUsize, Ordering};
 use std::time::Duration;
+
+use criterion::{criterion_group, criterion_main, BatchSize, Criterion};
 use tokio::runtime::Runtime;
 use tokio::task;
 
@@ -10,10 +12,10 @@ fn collect_gc_twice(lua: &Lua) {
     lua.gc_collect().unwrap();
 }
 
-fn create_table(c: &mut Criterion) {
+fn table_create_empty(c: &mut Criterion) {
     let lua = Lua::new();
 
-    c.bench_function("create [table empty]", |b| {
+    c.bench_function("table [create empty]", |b| {
         b.iter_batched(
             || collect_gc_twice(&lua),
             |_| {
@@ -24,35 +26,33 @@ fn create_table(c: &mut Criterion) {
     });
 }
 
-fn create_array(c: &mut Criterion) {
+fn table_create_array(c: &mut Criterion) {
     let lua = Lua::new();
 
-    c.bench_function("create [array] 10", |b| {
+    c.bench_function("table [create array]", |b| {
         b.iter_batched(
             || collect_gc_twice(&lua),
             |_| {
-                let table = lua.create_table().unwrap();
-                for i in 1..=10 {
-                    table.set(i, i).unwrap();
-                }
+                lua.create_sequence_from(1..=10).unwrap();
             },
             BatchSize::SmallInput,
         );
     });
 }
 
-fn create_string_table(c: &mut Criterion) {
+fn table_create_hash(c: &mut Criterion) {
     let lua = Lua::new();
 
-    c.bench_function("create [table string] 10", |b| {
+    c.bench_function("table [create hash]", |b| {
         b.iter_batched(
             || collect_gc_twice(&lua),
             |_| {
-                let table = lua.create_table().unwrap();
-                for &s in &["1", "2", "3", "4", "5", "6", "7", "8", "9", "10"] {
-                    let s = lua.create_string(s).unwrap();
-                    table.set(s.clone(), s).unwrap();
-                }
+                lua.create_table_from(
+                    ["1", "2", "3", "4", "5", "6", "7", "8", "9", "10"]
+                        .into_iter()
+                        .map(|s| (s, s)),
+                )
+                .unwrap();
             },
             BatchSize::SmallInput,
         );
@@ -62,17 +62,15 @@ fn create_string_table(c: &mut Criterion) {
 fn table_get_set(c: &mut Criterion) {
     let lua = Lua::new();
 
-    let table = lua.create_table().unwrap();
-
-    c.bench_function("table raw_get and raw_set [10]", |b| {
+    c.bench_function("table [get and set]", |b| {
         b.iter_batched(
             || {
                 collect_gc_twice(&lua);
-                table.clear().unwrap();
+                lua.create_table().unwrap()
             },
-            |_| {
-                for (i, &s) in ["a", "b", "c", "d", "e", "f", "g", "h", "i", "j"]
-                    .iter()
+            |table| {
+                for (i, s) in ["a", "b", "c", "d", "e", "f", "g", "h", "i", "j"]
+                    .into_iter()
                     .enumerate()
                 {
                     table.raw_set(s, i).unwrap();
@@ -87,7 +85,7 @@ fn table_get_set(c: &mut Criterion) {
 fn table_traversal_pairs(c: &mut Criterion) {
     let lua = Lua::new();
 
-    c.bench_function("table traversal [pairs]", |b| {
+    c.bench_function("table [traversal pairs]", |b| {
         b.iter_batched(
             || lua.globals(),
             |globals| {
@@ -103,7 +101,7 @@ fn table_traversal_pairs(c: &mut Criterion) {
 fn table_traversal_for_each(c: &mut Criterion) {
     let lua = Lua::new();
 
-    c.bench_function("table traversal [for_each]", |b| {
+    c.bench_function("table [traversal for_each]", |b| {
         b.iter_batched(
             || lua.globals(),
             |globals| globals.for_each::<String, LuaValue>(|_k, _v| Ok(())),
@@ -117,7 +115,7 @@ fn table_traversal_sequence(c: &mut Criterion) {
 
     let table = lua.create_sequence_from(1..1000).unwrap();
 
-    c.bench_function("table traversal [sequence]", |b| {
+    c.bench_function("table [traversal sequence]", |b| {
         b.iter_batched(
             || table.clone(),
             |table| {
@@ -130,236 +128,255 @@ fn table_traversal_sequence(c: &mut Criterion) {
     });
 }
 
-fn create_function(c: &mut Criterion) {
+fn function_create(c: &mut Criterion) {
     let lua = Lua::new();
 
-    c.bench_function("create [function] 10", |b| {
+    c.bench_function("function [create Rust]", |b| {
         b.iter_batched(
             || collect_gc_twice(&lua),
             |_| {
-                for i in 0..10 {
-                    lua.create_function(move |_, ()| Ok(i)).unwrap();
-                }
+                lua.create_function(|_, ()| Ok(123)).unwrap();
             },
             BatchSize::SmallInput,
         );
     });
 }
 
-fn call_lua_function(c: &mut Criterion) {
+fn function_call_sum(c: &mut Criterion) {
     let lua = Lua::new();
 
-    c.bench_function("call Lua function [sum] 3 10", |b| {
-        b.iter_batched_ref(
-            || {
-                collect_gc_twice(&lua);
-                lua.load("function(a, b, c) return a + b + c end")
-                    .eval::<LuaFunction>()
-                    .unwrap()
-            },
-            |function| {
-                for i in 0..10 {
-                    let _result: i64 = function.call((i, i + 1, i + 2)).unwrap();
-                }
-            },
-            BatchSize::SmallInput,
-        );
-    });
-}
-
-fn call_sum_callback(c: &mut Criterion) {
-    let lua = Lua::new();
-    let callback = lua
-        .create_function(|_, (a, b, c): (i64, i64, i64)| Ok(a + b + c))
+    let sum = lua
+        .create_function(|_, (a, b, c): (i64, i64, i64)| Ok(a + b - c))
         .unwrap();
-    lua.globals().set("callback", callback).unwrap();
 
-    c.bench_function("call Rust callback [sum] 3 10", |b| {
-        b.iter_batched_ref(
-            || {
-                collect_gc_twice(&lua);
-                lua.load("function() for i = 1,10 do callback(i, i+1, i+2) end end")
-                    .eval::<LuaFunction>()
-                    .unwrap()
-            },
-            |function| {
-                function.call::<_, ()>(()).unwrap();
+    c.bench_function("function [call Rust sum]", |b| {
+        b.iter_batched(
+            || collect_gc_twice(&lua),
+            |_| {
+                assert_eq!(sum.call::<_, i64>((10, 20, 30)).unwrap(), 0);
             },
             BatchSize::SmallInput,
         );
     });
 }
 
-fn call_async_sum_callback(c: &mut Criterion) {
-    let options = LuaOptions::new().thread_pool_size(1024);
-    let lua = Lua::new_with(LuaStdLib::ALL_SAFE, options).unwrap();
-    let callback = lua
-        .create_async_function(|_, (a, b, c): (i64, i64, i64)| async move {
-            task::yield_now().await;
-            Ok(a + b + c)
-        })
-        .unwrap();
-    lua.globals().set("callback", callback).unwrap();
-
-    c.bench_function("call async Rust callback [sum] 3 10", |b| {
-        let rt = Runtime::new().unwrap();
-        b.to_async(rt).iter_batched(
-            || {
-                collect_gc_twice(&lua);
-                lua.load("function() for i = 1,10 do callback(i, i+1, i+2) end end")
-                    .eval::<LuaFunction>()
-                    .unwrap()
-            },
-            |function| async move {
-                function.call_async::<_, ()>(()).await.unwrap();
-            },
-            BatchSize::SmallInput,
-        );
-    });
-}
-
-fn call_concat_callback(c: &mut Criterion) {
+fn function_call_lua_sum(c: &mut Criterion) {
     let lua = Lua::new();
-    let callback = lua
+
+    let sum = lua
+        .load("function(a, b, c) return a + b - c end")
+        .eval::<LuaFunction>()
+        .unwrap();
+
+    c.bench_function("function [call Lua sum]", |b| {
+        b.iter_batched(
+            || collect_gc_twice(&lua),
+            |_| {
+                assert_eq!(sum.call::<_, i64>((10, 20, 30)).unwrap(), 0);
+            },
+            BatchSize::SmallInput,
+        );
+    });
+}
+
+fn function_call_concat(c: &mut Criterion) {
+    let lua = Lua::new();
+
+    let concat = lua
         .create_function(|_, (a, b): (LuaString, LuaString)| {
             Ok(format!("{}{}", a.to_str()?, b.to_str()?))
         })
         .unwrap();
-    lua.globals().set("callback", callback).unwrap();
+    let i = AtomicUsize::new(0);
 
-    c.bench_function("call Rust callback [concat string] 10", |b| {
-        b.iter_batched_ref(
+    c.bench_function("function [call Rust concat string]", |b| {
+        b.iter_batched(
             || {
                 collect_gc_twice(&lua);
-                lua.load("function() for i = 1,10 do callback('a', tostring(i)) end end")
-                    .eval::<LuaFunction>()
-                    .unwrap()
+                i.fetch_add(1, Ordering::Relaxed)
             },
-            |function| {
-                function.call::<_, ()>(()).unwrap();
+            |i| {
+                assert_eq!(
+                    concat.call::<_, LuaString>(("num:", i)).unwrap(),
+                    format!("num:{i}")
+                );
             },
             BatchSize::SmallInput,
         );
     });
 }
 
-fn create_registry_values(c: &mut Criterion) {
+fn function_call_lua_concat(c: &mut Criterion) {
     let lua = Lua::new();
 
-    c.bench_function("create [registry value] 10", |b| {
+    let concat = lua
+        .load("function(a, b) return a..b end")
+        .eval::<LuaFunction>()
+        .unwrap();
+    let i = AtomicUsize::new(0);
+
+    c.bench_function("function [call Lua concat string]", |b| {
         b.iter_batched(
-            || collect_gc_twice(&lua),
-            |_| {
-                for _ in 0..10 {
-                    lua.create_registry_value(lua.pack(true).unwrap()).unwrap();
-                }
-                lua.expire_registry_values();
+            || {
+                collect_gc_twice(&lua);
+                i.fetch_add(1, Ordering::Relaxed)
+            },
+            |i| {
+                assert_eq!(
+                    concat.call::<_, LuaString>(("num:", i)).unwrap(),
+                    format!("num:{i}")
+                );
             },
             BatchSize::SmallInput,
         );
     });
 }
 
-fn create_userdata(c: &mut Criterion) {
-    struct UserData(i64);
+fn function_async_call_sum(c: &mut Criterion) {
+    let options = LuaOptions::new().thread_pool_size(1024);
+    let lua = Lua::new_with(LuaStdLib::ALL_SAFE, options).unwrap();
+
+    let sum = lua
+        .create_async_function(|_, (a, b, c): (i64, i64, i64)| async move {
+            task::yield_now().await;
+            Ok(a + b - c)
+        })
+        .unwrap();
+
+    c.bench_function("function [async call Rust sum]", |b| {
+        let rt = Runtime::new().unwrap();
+        b.to_async(rt).iter_batched(
+            || collect_gc_twice(&lua),
+            |_| async {
+                assert_eq!(sum.call_async::<_, i64>((10, 20, 30)).await.unwrap(), 0);
+            },
+            BatchSize::SmallInput,
+        );
+    });
+}
+
+fn registry_value_create(c: &mut Criterion) {
+    let lua = Lua::new();
+    lua.gc_stop();
+
+    c.bench_function("registry value [create]", |b| {
+        b.iter_batched(
+            || collect_gc_twice(&lua),
+            |_| lua.create_registry_value("hello").unwrap(),
+            BatchSize::SmallInput,
+        );
+    });
+}
+
+fn userdata_create(c: &mut Criterion) {
+    struct UserData(#[allow(unused)] i64);
     impl LuaUserData for UserData {}
 
     let lua = Lua::new();
 
-    c.bench_function("create [table userdata] 10", |b| {
+    c.bench_function("userdata [create]", |b| {
         b.iter_batched(
             || collect_gc_twice(&lua),
             |_| {
-                let table: LuaTable = lua.create_table().unwrap();
-                for i in 1..11 {
-                    table.set(i, UserData(i)).unwrap();
-                }
+                lua.create_userdata(UserData(123)).unwrap();
             },
             BatchSize::SmallInput,
         );
     });
 }
 
-fn call_userdata_index(c: &mut Criterion) {
-    struct UserData(i64);
+fn userdata_call_index(c: &mut Criterion) {
+    struct UserData(#[allow(unused)] i64);
     impl LuaUserData for UserData {
         fn add_methods<'lua, M: LuaUserDataMethods<'lua, Self>>(methods: &mut M) {
-            methods.add_meta_method(LuaMetaMethod::Index, move |_, _, index: String| Ok(index));
+            methods.add_meta_method(LuaMetaMethod::Index, move |_, _, key: LuaString| Ok(key));
         }
     }
 
     let lua = Lua::new();
-    lua.globals().set("userdata", UserData(10)).unwrap();
+    let ud = lua.create_userdata(UserData(123)).unwrap();
+    let index = lua
+        .load("function(ud) return ud.test end")
+        .eval::<LuaFunction>()
+        .unwrap();
 
-    c.bench_function("call [userdata index] 10", |b| {
-        b.iter_batched_ref(
-            || {
-                collect_gc_twice(&lua);
-                lua.load("function() for i = 1,10 do local v = userdata.test end end")
-                    .eval::<LuaFunction>()
-                    .unwrap()
-            },
-            |function| {
-                function.call::<_, ()>(()).unwrap();
+    c.bench_function("userdata [call index]", |b| {
+        b.iter_batched(
+            || collect_gc_twice(&lua),
+            |_| {
+                assert_eq!(index.call::<_, LuaString>(&ud).unwrap(), "test");
             },
             BatchSize::SmallInput,
         );
     });
 }
 
-fn call_userdata_method(c: &mut Criterion) {
+fn userdata_call_method(c: &mut Criterion) {
     struct UserData(i64);
     impl LuaUserData for UserData {
         fn add_methods<'lua, M: LuaUserDataMethods<'lua, Self>>(methods: &mut M) {
-            methods.add_method("method", |_, this, ()| Ok(this.0));
+            methods.add_method("add", |_, this, i: i64| Ok(this.0 + i));
         }
     }
 
     let lua = Lua::new();
-    lua.globals().set("userdata", UserData(10)).unwrap();
+    let ud = lua.create_userdata(UserData(123)).unwrap();
+    let method = lua
+        .load("function(ud, i) return ud:add(i) end")
+        .eval::<LuaFunction>()
+        .unwrap();
+    let i = AtomicUsize::new(0);
 
-    c.bench_function("call [userdata method] 10", |b| {
-        b.iter_batched_ref(
+    c.bench_function("userdata [call method]", |b| {
+        b.iter_batched(
             || {
                 collect_gc_twice(&lua);
-                lua.load("function() for i = 1,10 do userdata:method() end end")
-                    .eval::<LuaFunction>()
-                    .unwrap()
+                i.fetch_add(1, Ordering::Relaxed)
             },
-            |function| {
-                function.call::<_, ()>(()).unwrap();
+            |i| {
+                assert_eq!(method.call::<_, usize>((&ud, i)).unwrap(), 123 + i);
             },
             BatchSize::SmallInput,
         );
     });
 }
 
-fn call_async_userdata_method(c: &mut Criterion) {
-    struct UserData(String);
-
+fn userdata_async_call_method(c: &mut Criterion) {
+    struct UserData(i64);
     impl LuaUserData for UserData {
         fn add_methods<'lua, M: LuaUserDataMethods<'lua, Self>>(methods: &mut M) {
-            methods.add_async_method("method", |_, this, ()| async move { Ok(this.0.clone()) });
+            methods.add_async_method("add", |_, this, i: i64| async move {
+                task::yield_now().await;
+                Ok(this.0 + i)
+            });
         }
     }
 
     let options = LuaOptions::new().thread_pool_size(1024);
     let lua = Lua::new_with(LuaStdLib::ALL_SAFE, options).unwrap();
-    lua.globals()
-        .set("userdata", UserData("hello".to_string()))
+    let ud = lua.create_userdata(UserData(123)).unwrap();
+    let method = lua
+        .load("function(ud, i) return ud:add(i) end")
+        .eval::<LuaFunction>()
         .unwrap();
+    let i = AtomicUsize::new(0);
 
-    c.bench_function("call async [userdata method] 10", |b| {
+    c.bench_function("userdata [async call method] 10", |b| {
         let rt = Runtime::new().unwrap();
         b.to_async(rt).iter_batched(
             || {
                 collect_gc_twice(&lua);
-                lua.load("function() for i = 1,10 do userdata:method() end end")
-                    .eval::<LuaFunction>()
-                    .unwrap()
+                (
+                    method.clone(),
+                    ud.clone(),
+                    i.fetch_add(1, Ordering::Relaxed),
+                )
             },
-            |function| async move {
-                function.call_async::<_, ()>(()).await.unwrap();
+            |(method, ud, i)| async move {
+                assert_eq!(
+                    method.call_async::<_, usize>((ud, i)).await.unwrap(),
+                    123 + i
+                );
             },
             BatchSize::SmallInput,
         );
@@ -369,27 +386,31 @@ fn call_async_userdata_method(c: &mut Criterion) {
 criterion_group! {
     name = benches;
     config = Criterion::default()
-        .sample_size(300)
+        .sample_size(500)
         .measurement_time(Duration::from_secs(10))
         .noise_threshold(0.02);
     targets =
-        create_table,
-        create_array,
-        create_string_table,
+        table_create_empty,
+        table_create_array,
+        table_create_hash,
         table_get_set,
         table_traversal_pairs,
         table_traversal_for_each,
         table_traversal_sequence,
-        create_function,
-        call_lua_function,
-        call_sum_callback,
-        call_async_sum_callback,
-        call_concat_callback,
-        create_registry_values,
-        create_userdata,
-        call_userdata_index,
-        call_userdata_method,
-        call_async_userdata_method,
+
+        function_create,
+        function_call_sum,
+        function_call_lua_sum,
+        function_call_concat,
+        function_call_lua_concat,
+        function_async_call_sum,
+
+        registry_value_create,
+
+        userdata_create,
+        userdata_call_index,
+        userdata_call_method,
+        userdata_async_call_method,
 }
 
 criterion_main!(benches);

benches/serde.rs

@@ -1,6 +1,7 @@
-use criterion::{criterion_group, criterion_main, BatchSize, Criterion};
 use std::time::Duration;
 
+use criterion::{criterion_group, criterion_main, BatchSize, Criterion};
+
 use mlua::prelude::*;
 
 fn collect_gc_twice(lua: &Lua) {
@@ -8,43 +9,67 @@ fn collect_gc_twice(lua: &Lua) {
     lua.gc_collect().unwrap();
 }
 
-fn serialize_json(c: &mut Criterion) {
+fn encode_json(c: &mut Criterion) {
     let lua = Lua::new();
 
-    lua.globals()
-        .set(
-            "encode",
-            LuaFunction::wrap(|_, t: LuaValue| Ok(serde_json::to_string(&t).unwrap())),
+    let encode = lua
+        .create_function(|_, t: LuaValue| Ok(serde_json::to_string(&t).unwrap()))
+        .unwrap();
+    let table = lua
+        .load(
+            r#"{
+        name = "Clark Kent",
+        address = {
+            city = "Smallville",
+            state = "Kansas",
+            country = "USA",
+        },
+        age = 22,
+        parents = {"Jonathan Kent", "Martha Kent"},
+        superman = true,
+        interests = {"flying", "saving the world", "kryptonite"},
+    }"#,
         )
+        .eval::<LuaTable>()
         .unwrap();
 
-    c.bench_function("serialize table to json [10]", |b| {
+    c.bench_function("serialize json", |b| {
         b.iter_batched(
-            || {
-                collect_gc_twice(&lua);
-                lua.load(
-                    r#"
-                local encode = encode
-                return function()
-                    for i = 1, 10 do
-                        encode({
-                            name = "Clark Kent",
-                            nickname = "Superman",
-                            address = {
-                                city = "Metropolis",
-                            },
-                            age = 32,
-                            superman = true,
-                        })
-                    end
-                end
-            "#,
-                )
-                .eval::<LuaFunction>()
-                .unwrap()
+            || collect_gc_twice(&lua),
+            |_| {
+                encode.call::<_, LuaString>(&table).unwrap();
             },
-            |func| {
-                func.call::<_, ()>(()).unwrap();
+            BatchSize::SmallInput,
+        );
+    });
+}
+
+fn decode_json(c: &mut Criterion) {
+    let lua = Lua::new();
+
+    let decode = lua
+        .create_function(|lua, s: String| {
+            lua.to_value(&serde_json::from_str::<serde_json::Value>(&s).unwrap())
+        })
+        .unwrap();
+    let json = r#"{
+        "name": "Clark Kent",
+        "address": {
+            "city": "Smallville",
+            "state": "Kansas",
+            "country": "USA"
+        },
+        "age": 22,
+        "parents": ["Jonathan Kent", "Martha Kent"],
+        "superman": true,
+        "interests": ["flying", "saving the world", "kryptonite"]
+    }"#;
+
+    c.bench_function("deserialize json", |b| {
+        b.iter_batched(
+            || collect_gc_twice(&lua),
+            |_| {
+                decode.call::<_, LuaTable>(json).unwrap();
             },
             BatchSize::SmallInput,
         );
@@ -54,11 +79,12 @@ fn serialize_json(c: &mut Criterion) {
 criterion_group! {
     name = benches;
     config = Criterion::default()
-        .sample_size(300)
+        .sample_size(500)
         .measurement_time(Duration::from_secs(10))
         .noise_threshold(0.02);
     targets =
-        serialize_json,
+        encode_json,
+        decode_json,
 }
 
 criterion_main!(benches);

examples/async_http_client.rs

@@ -1,18 +1,22 @@
 use std::collections::HashMap;
 
-use hyper::body::{Body as HyperBody, HttpBody as _};
-use hyper::Client as HyperClient;
+use http_body_util::BodyExt as _;
+use hyper::body::Incoming;
+use hyper_util::client::legacy::Client as HyperClient;
+use hyper_util::rt::TokioExecutor;
 
 use mlua::{chunk, ExternalResult, Lua, Result, UserData, UserDataMethods};
 
-struct BodyReader(HyperBody);
+struct BodyReader(Incoming);
 
 impl UserData for BodyReader {
     fn add_methods<'lua, M: UserDataMethods<'lua, Self>>(methods: &mut M) {
+        // Every call returns a next chunk
         methods.add_async_method_mut("read", |lua, reader, ()| async move {
-            if let Some(bytes) = reader.0.data().await {
-                let bytes = bytes.into_lua_err()?;
-                return Some(lua.create_string(&bytes)).transpose();
+            if let Some(bytes) = reader.0.frame().await {
+                if let Some(bytes) = bytes.into_lua_err()?.data_ref() {
+                    return Some(lua.create_string(&bytes)).transpose();
+                }
             }
             Ok(None)
         });
@@ -24,7 +28,7 @@ async fn main() -> Result<()> {
     let lua = Lua::new();
 
     let fetch_url = lua.create_async_function(|lua, uri: String| async move {
-        let client = HyperClient::new();
+        let client = HyperClient::builder(TokioExecutor::new()).build_http::<String>();
         let uri = uri.parse().into_lua_err()?;
         let resp = client.get(uri).await.into_lua_err()?;
 
@@ -55,11 +59,11 @@ async fn main() -> Result<()> {
                 end
             end
             repeat
-                local body = res.body:read()
-                if body then
-                    print(body)
+                local chunk = res.body:read()
+                if chunk then
+                    print(chunk)
                 end
-            until not body
+            until not chunk
         })
         .into_function()?;
 

examples/async_http_reqwest.rs

@@ -1,11 +1,9 @@
-use mlua::{chunk, ExternalResult, Lua, LuaSerdeExt, Result};
+use mlua::{chunk, ExternalResult, Lua, LuaSerdeExt, Result, Value};
 
 #[tokio::main(flavor = "current_thread")]
 async fn main() -> Result<()> {
     let lua = Lua::new();
 
-    let null = lua.null();
-
     let fetch_json = lua.create_async_function(|lua, uri: String| async move {
         let resp = reqwest::get(&uri)
             .await
@@ -15,19 +13,15 @@ async fn main() -> Result<()> {
         lua.to_value(&json)
     })?;
 
+    let dbg = lua.create_function(|_, value: Value| {
+        println!("{value:#?}");
+        Ok(())
+    })?;
+
     let f = lua
         .load(chunk! {
-            function print_r(t, indent)
-                local indent = indent or ""
-                for k, v in pairs(t) do
-                    io.write(indent, tostring(k))
-                    if type(v) == "table" then io.write(":\n") print_r(v, indent.."  ")
-                    else io.write(": ", v == $null and "null" or tostring(v), "\n") end
-                end
-            end
-
             local res = $fetch_json(...)
-            print_r(res)
+            $dbg(res)
         })
         .into_function()?;
 

examples/async_http_server.rs

@@ -1,43 +1,63 @@
+use std::convert::Infallible;
 use std::future::Future;
 use std::net::SocketAddr;
-use std::pin::Pin;
 use std::rc::Rc;
-use std::task::{Context, Poll};
 
-use hyper::server::conn::AddrStream;
-use hyper::service::Service;
-use hyper::{Body, Request, Response, Server};
+use futures::future::LocalBoxFuture;
+use http_body_util::{combinators::BoxBody, BodyExt as _, Empty, Full};
+use hyper::body::{Bytes, Incoming};
+use hyper::{Request, Response};
+use hyper_util::rt::TokioIo;
+use hyper_util::server::conn::auto::Builder as ServerConnBuilder;
+use tokio::net::TcpListener;
+use tokio::task::LocalSet;
 
 use mlua::{
-    chunk, Error as LuaError, Function, Lua, String as LuaString, Table, UserData, UserDataMethods,
+    chunk, Error as LuaError, Function, Lua, RegistryKey, String as LuaString, Table, UserData,
+    UserDataMethods,
 };
 
-struct LuaRequest(SocketAddr, Request<Body>);
+/// Wrapper around incoming request that implements UserData
+struct LuaRequest(SocketAddr, Request<Incoming>);
 
 impl UserData for LuaRequest {
     fn add_methods<'lua, M: UserDataMethods<'lua, Self>>(methods: &mut M) {
-        methods.add_method("remote_addr", |_lua, req, ()| Ok((req.0).to_string()));
-        methods.add_method("method", |_lua, req, ()| Ok((req.1).method().to_string()));
+        methods.add_method("remote_addr", |_, req, ()| Ok((req.0).to_string()));
+        methods.add_method("method", |_, req, ()| Ok((req.1).method().to_string()));
+        methods.add_method("path", |_, req, ()| Ok(req.1.uri().path().to_string()));
     }
 }
 
-pub struct Svc(Rc<Lua>, SocketAddr);
+/// Service that handles incoming requests
+#[derive(Clone)]
+pub struct Svc {
+    lua: Rc<Lua>,
+    handler: Rc<RegistryKey>,
+    peer_addr: SocketAddr,
+}
 
-impl Service<Request<Body>> for Svc {
-    type Response = Response<Body>;
-    type Error = LuaError;
-    type Future = Pin<Box<dyn Future<Output = Result<Self::Response, Self::Error>>>>;
-
-    fn poll_ready(&mut self, _cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
-        Poll::Ready(Ok(()))
+impl Svc {
+    pub fn new(lua: Rc<Lua>, handler: Rc<RegistryKey>, peer_addr: SocketAddr) -> Self {
+        Self {
+            lua,
+            handler,
+            peer_addr,
+        }
     }
+}
 
-    fn call(&mut self, req: Request<Body>) -> Self::Future {
+impl hyper::service::Service<Request<Incoming>> for Svc {
+    type Response = Response<BoxBody<Bytes, Infallible>>;
+    type Error = LuaError;
+    type Future = LocalBoxFuture<'static, Result<Self::Response, Self::Error>>;
+
+    fn call(&self, req: Request<Incoming>) -> Self::Future {
         // If handler returns an error then generate 5xx response
-        let lua = self.0.clone();
-        let lua_req = LuaRequest(self.1, req);
+        let lua = self.lua.clone();
+        let handler_key = self.handler.clone();
+        let lua_req = LuaRequest(self.peer_addr, req);
         Box::pin(async move {
-            let handler: Function = lua.named_registry_value("http_handler")?;
+            let handler: Function = lua.registry_value(&handler_key)?;
             match handler.call_async::<_, Table>(lua_req).await {
                 Ok(lua_resp) => {
                     let status = lua_resp.get::<_, Option<u16>>("status")?.unwrap_or(200);
@@ -51,10 +71,11 @@ impl Service<Request<Body>> for Svc {
                         }
                     }
 
+                    // Set body
                     let body = lua_resp
                         .get::<_, Option<LuaString>>("body")?
-                        .map(|b| Body::from(b.as_bytes().to_vec()))
-                        .unwrap_or_else(Body::empty);
+                        .map(|b| Full::new(Bytes::copy_from_slice(b.as_bytes())).boxed())
+                        .unwrap_or_else(|| Empty::<Bytes>::new().boxed());
 
                     Ok(resp.body(body).unwrap())
                 }
@@ -62,7 +83,7 @@ impl Service<Request<Body>> for Svc {
                     eprintln!("{}", err);
                     Ok(Response::builder()
                         .status(500)
-                        .body(Body::from("Internal Server Error"))
+                        .body(Full::new(Bytes::from("Internal Server Error")).boxed())
                         .unwrap())
                 }
             }
@@ -75,13 +96,14 @@ async fn main() {
     let lua = Rc::new(Lua::new());
 
     // Create Lua handler function
-    let handler: Function = lua
+    let handler: RegistryKey = lua
         .load(chunk! {
             function(req)
                 return {
                     status = 200,
                     headers = {
                         ["X-Req-Method"] = req:method(),
+                        ["X-Req-Path"] = req:path(),
                         ["X-Remote-Addr"] = req:remote_addr(),
                     },
                     body = "Hello from Lua!\n"
@@ -89,37 +111,35 @@ async fn main() {
             end
         })
         .eval()
-        .expect("cannot create Lua handler");
+        .expect("Failed to create Lua handler");
+    let handler = Rc::new(handler);
 
-    // Store it in the Registry
-    lua.set_named_registry_value("http_handler", handler)
-        .expect("cannot store Lua handler");
+    let listen_addr = "127.0.0.1:3000";
+    let listener = TcpListener::bind(listen_addr).await.unwrap();
+    println!("Listening on http://{listen_addr}");
 
-    let addr = ([127, 0, 0, 1], 3000).into();
-    let server = Server::bind(&addr).executor(LocalExec).serve(MakeSvc(lua));
+    let local = LocalSet::new();
+    loop {
+        let (stream, peer_addr) = match listener.accept().await {
+            Ok(x) => x,
+            Err(err) => {
+                eprintln!("Failed to accept connection: {err}");
+                continue;
+            }
+        };
 
-    println!("Listening on http://{}", addr);
-
-    // Create `LocalSet` to spawn !Send futures
-    let local = tokio::task::LocalSet::new();
-    local.run_until(server).await.expect("cannot run server")
-}
-
-struct MakeSvc(Rc<Lua>);
-
-impl Service<&AddrStream> for MakeSvc {
-    type Response = Svc;
-    type Error = hyper::Error;
-    type Future = Pin<Box<dyn Future<Output = Result<Self::Response, Self::Error>>>>;
-
-    fn poll_ready(&mut self, _: &mut Context) -> Poll<Result<(), Self::Error>> {
-        Poll::Ready(Ok(()))
-    }
-
-    fn call(&mut self, stream: &AddrStream) -> Self::Future {
-        let lua = self.0.clone();
-        let remote_addr = stream.remote_addr();
-        Box::pin(async move { Ok(Svc(lua, remote_addr)) })
+        let svc = Svc::new(lua.clone(), handler.clone(), peer_addr);
+        local
+            .run_until(async move {
+                let result = ServerConnBuilder::new(LocalExec)
+                    .http1()
+                    .serve_connection(TokioIo::new(stream), svc)
+                    .await;
+                if let Err(err) = result {
+                    eprintln!("Error serving connection: {err:?}");
+                }
+            })
+            .await;
     }
 }
 
@@ -128,7 +148,7 @@ struct LocalExec;
 
 impl<F> hyper::rt::Executor<F> for LocalExec
 where
-    F: std::future::Future + 'static, // not requiring `Send`
+    F: Future + 'static, // not requiring `Send`
 {
     fn execute(&self, fut: F) {
         tokio::task::spawn_local(fut);

mlua-sys/src/lua51/compat.rs

@@ -2,7 +2,6 @@
 //!
 //! Based on github.com/keplerproject/lua-compat-5.3
 
-use std::convert::TryInto;
 use std::mem;
 use std::os::raw::{c_char, c_int, c_void};
 use std::ptr;

mlua-sys/src/lua52/compat.rs

@@ -2,7 +2,6 @@
 //!
 //! Based on github.com/keplerproject/lua-compat-5.3
 
-use std::convert::TryInto;
 use std::os::raw::{c_char, c_int, c_void};
 use std::ptr;
 

mlua-sys/src/luau/lauxlib.rs

@@ -144,9 +144,12 @@ pub unsafe fn luaL_sandbox(L: *mut lua_State, enabled: c_int) {
 
     // set all builtin metatables to read-only
     lua_pushliteral(L, "");
-    lua_getmetatable(L, -1);
-    lua_setreadonly(L, -1, enabled);
-    lua_pop(L, 2);
+    if lua_getmetatable(L, -1) != 0 {
+        lua_setreadonly(L, -1, enabled);
+        lua_pop(L, 2);
+    } else {
+        lua_pop(L, 1);
+    }
 
     // set globals to readonly and activate safeenv since the env is immutable
     lua_setreadonly(L, LUA_GLOBALSINDEX, enabled);

mlua-sys/src/luau/luacode.rs

@@ -36,6 +36,7 @@ pub unsafe fn luau_compile(source: &[u8], mut options: lua_CompileOptions) -> Ve
         &mut options,
         &mut outsize,
     );
+    assert!(!data_ptr.is_null(), "luau_compile failed");
     let data = slice::from_raw_parts(data_ptr as *mut u8, outsize).to_vec();
     free(data_ptr as *mut c_void);
     data

mlua_derive/src/token.rs

@@ -1,7 +1,6 @@
 use std::{
     cmp::{Eq, PartialEq},
     fmt::{self, Display, Formatter},
-    iter::IntoIterator,
     vec::IntoIter,
 };
 

src/conversion.rs

@@ -1,6 +1,5 @@
 use std::borrow::Cow;
 use std::collections::{BTreeMap, BTreeSet, HashMap, HashSet};
-use std::convert::TryInto;
 use std::ffi::{CStr, CString};
 use std::hash::{BuildHasher, Hash};
 use std::os::raw::c_int;
@@ -33,6 +32,18 @@ impl<'lua> IntoLua<'lua> for Value<'lua> {
     }
 }
 
+impl<'lua> IntoLua<'lua> for &Value<'lua> {
+    #[inline]
+    fn into_lua(self, _: &'lua Lua) -> Result<Value<'lua>> {
+        Ok(self.clone())
+    }
+
+    #[inline]
+    unsafe fn push_into_stack(self, lua: &'lua Lua) -> Result<()> {
+        lua.push_value_ref(self)
+    }
+}
+
 impl<'lua> FromLua<'lua> for Value<'lua> {
     #[inline]
     fn from_lua(lua_value: Value<'lua>, _: &'lua Lua) -> Result<Self> {
@@ -55,7 +66,8 @@ impl<'lua> IntoLua<'lua> for &String<'lua> {
 
     #[inline]
     unsafe fn push_into_stack(self, lua: &'lua Lua) -> Result<()> {
-        Ok(lua.push_ref(&self.0))
+        lua.push_ref(&self.0);
+        Ok(())
     }
 }
 
@@ -91,7 +103,8 @@ impl<'lua> IntoLua<'lua> for &OwnedString {
 
     #[inline]
     unsafe fn push_into_stack(self, lua: &'lua Lua) -> Result<()> {
-        Ok(lua.push_owned_ref(&self.0))
+        lua.push_owned_ref(&self.0);
+        Ok(())
     }
 }
 
@@ -119,7 +132,8 @@ impl<'lua> IntoLua<'lua> for &Table<'lua> {
 
     #[inline]
     unsafe fn push_into_stack(self, lua: &'lua Lua) -> Result<()> {
-        Ok(lua.push_ref(&self.0))
+        lua.push_ref(&self.0);
+        Ok(())
     }
 }
 
@@ -156,7 +170,8 @@ impl<'lua> IntoLua<'lua> for &OwnedTable {
 
     #[inline]
     unsafe fn push_into_stack(self, lua: &'lua Lua) -> Result<()> {
-        Ok(lua.push_owned_ref(&self.0))
+        lua.push_owned_ref(&self.0);
+        Ok(())
     }
 }
 
@@ -184,7 +199,8 @@ impl<'lua> IntoLua<'lua> for &Function<'lua> {
 
     #[inline]
     unsafe fn push_into_stack(self, lua: &'lua Lua) -> Result<()> {
-        Ok(lua.push_ref(&self.0))
+        lua.push_ref(&self.0);
+        Ok(())
     }
 }
 
@@ -221,7 +237,8 @@ impl<'lua> IntoLua<'lua> for &OwnedFunction {
 
     #[inline]
     unsafe fn push_into_stack(self, lua: &'lua Lua) -> Result<()> {
-        Ok(lua.push_owned_ref(&self.0))
+        lua.push_owned_ref(&self.0);
+        Ok(())
     }
 }
 
@@ -249,7 +266,8 @@ impl<'lua> IntoLua<'lua> for &Thread<'lua> {
 
     #[inline]
     unsafe fn push_into_stack(self, lua: &'lua Lua) -> Result<()> {
-        Ok(lua.push_ref(&self.0))
+        lua.push_ref(&self.0);
+        Ok(())
     }
 }
 
@@ -286,7 +304,8 @@ impl<'lua> IntoLua<'lua> for &OwnedThread {
 
     #[inline]
     unsafe fn push_into_stack(self, lua: &'lua Lua) -> Result<()> {
-        Ok(lua.push_owned_ref(&self.0))
+        lua.push_owned_ref(&self.0);
+        Ok(())
     }
 }
 
@@ -314,7 +333,8 @@ impl<'lua> IntoLua<'lua> for &AnyUserData<'lua> {
 
     #[inline]
     unsafe fn push_into_stack(self, lua: &'lua Lua) -> Result<()> {
-        Ok(lua.push_ref(&self.0))
+        lua.push_ref(&self.0);
+        Ok(())
     }
 }
 
@@ -354,7 +374,8 @@ impl<'lua> IntoLua<'lua> for &OwnedAnyUserData {
 
     #[inline]
     unsafe fn push_into_stack(self, lua: &'lua Lua) -> Result<()> {
-        Ok(lua.push_owned_ref(&self.0))
+        lua.push_owned_ref(&self.0);
+        Ok(())
     }
 }
 
@@ -409,6 +430,18 @@ impl<'lua> FromLua<'lua> for Error {
     }
 }
 
+impl<'lua> IntoLua<'lua> for RegistryKey {
+    #[inline]
+    fn into_lua(self, lua: &'lua Lua) -> Result<Value<'lua>> {
+        lua.registry_value(&self)
+    }
+
+    #[inline]
+    unsafe fn push_into_stack(self, lua: &'lua Lua) -> Result<()> {
+        <&RegistryKey>::push_into_stack(&self, lua)
+    }
+}
+
 impl<'lua> IntoLua<'lua> for &RegistryKey {
     #[inline]
     fn into_lua(self, lua: &'lua Lua) -> Result<Value<'lua>> {
@@ -429,11 +462,24 @@ impl<'lua> IntoLua<'lua> for &RegistryKey {
     }
 }
 
+impl<'lua> FromLua<'lua> for RegistryKey {
+    #[inline]
+    fn from_lua(value: Value<'lua>, lua: &'lua Lua) -> Result<RegistryKey> {
+        lua.create_registry_value(value)
+    }
+}
+
 impl<'lua> IntoLua<'lua> for bool {
     #[inline]
     fn into_lua(self, _: &'lua Lua) -> Result<Value<'lua>> {
         Ok(Value::Boolean(self))
     }
+
+    #[inline]
+    unsafe fn push_into_stack(self, lua: &'lua Lua) -> Result<()> {
+        ffi::lua_pushboolean(lua.state(), self as c_int);
+        Ok(())
+    }
 }
 
 impl<'lua> FromLua<'lua> for bool {
@@ -445,6 +491,11 @@ impl<'lua> FromLua<'lua> for bool {
             _ => Ok(true),
         }
     }
+
+    #[inline]
+    unsafe fn from_stack(idx: c_int, lua: &'lua Lua) -> Result<Self> {
+        Ok(ffi::lua_toboolean(lua.state(), idx) != 0)
+    }
 }
 
 impl<'lua> IntoLua<'lua> for LightUserData {
@@ -633,19 +684,49 @@ impl<'lua> IntoLua<'lua> for BString {
 }
 
 impl<'lua> FromLua<'lua> for BString {
-    #[inline]
     fn from_lua(value: Value<'lua>, lua: &'lua Lua) -> Result<Self> {
         let ty = value.type_name();
-        Ok(BString::from(
-            lua.coerce_string(value)?
+        match value {
+            Value::String(s) => Ok(s.as_bytes().into()),
+            #[cfg(feature = "luau")]
+            Value::UserData(ud) if ud.1 == crate::types::SubtypeId::Buffer => unsafe {
+                let mut size = 0usize;
+                let buf = ffi::lua_tobuffer(ud.0.lua.ref_thread(), ud.0.index, &mut size);
+                mlua_assert!(!buf.is_null(), "invalid Luau buffer");
+                Ok(slice::from_raw_parts(buf as *const u8, size).into())
+            },
+            _ => Ok(lua
+                .coerce_string(value)?
                 .ok_or_else(|| Error::FromLuaConversionError {
                     from: ty,
                     to: "BString",
                     message: Some("expected string or number".to_string()),
                 })?
                 .as_bytes()
-                .to_vec(),
-        ))
+                .into()),
+        }
+    }
+
+    unsafe fn from_stack(idx: c_int, lua: &'lua Lua) -> Result<Self> {
+        let state = lua.state();
+        match ffi::lua_type(state, idx) {
+            ffi::LUA_TSTRING => {
+                let mut size = 0;
+                let data = ffi::lua_tolstring(state, idx, &mut size);
+                Ok(slice::from_raw_parts(data as *const u8, size).into())
+            }
+            #[cfg(feature = "luau")]
+            ffi::LUA_TBUFFER => {
+                let mut size = 0;
+                let buf = ffi::lua_tobuffer(state, idx, &mut size);
+                mlua_assert!(!buf.is_null(), "invalid Luau buffer");
+                Ok(slice::from_raw_parts(buf as *const u8, size).into())
+            }
+            _ => {
+                // Fallback to default
+                Self::from_lua(lua.stack_value(idx), lua)
+            }
+        }
     }
 }
 
@@ -686,6 +767,15 @@ macro_rules! lua_convert_int {
                         message: Some("out of range".to_owned()),
                     })
             }
+
+            #[inline]
+            unsafe fn push_into_stack(self, lua: &'lua Lua) -> Result<()> {
+                match cast(self) {
+                    Some(i) => ffi::lua_pushinteger(lua.state(), i),
+                    None => ffi::lua_pushnumber(lua.state(), self as ffi::lua_Number),
+                }
+                Ok(())
+            }
         }
 
         impl<'lua> FromLua<'lua> for $x {
@@ -978,6 +1068,15 @@ impl<'lua, T: IntoLua<'lua>> IntoLua<'lua> for Option<T> {
             None => Ok(Nil),
         }
     }
+
+    #[inline]
+    unsafe fn push_into_stack(self, lua: &'lua Lua) -> Result<()> {
+        match self {
+            Some(val) => val.push_into_stack(lua)?,
+            None => ffi::lua_pushnil(lua.state()),
+        }
+        Ok(())
+    }
 }
 
 impl<'lua, T: FromLua<'lua>> FromLua<'lua> for Option<T> {
@@ -988,4 +1087,13 @@ impl<'lua, T: FromLua<'lua>> FromLua<'lua> for Option<T> {
             value => Ok(Some(T::from_lua(value, lua)?)),
         }
     }
+
+    #[inline]
+    unsafe fn from_stack(idx: c_int, lua: &'lua Lua) -> Result<Self> {
+        if ffi::lua_isnil(lua.state(), idx) != 0 {
+            Ok(None)
+        } else {
+            Ok(Some(T::from_stack(idx, lua)?))
+        }
+    }
 }

src/function.rs

@@ -494,6 +494,37 @@ impl<'lua> Function<'lua> {
         }
     }
 
+    /// Converts this function to a generic C pointer.
+    ///
+    /// There is no way to convert the pointer back to its original value.
+    ///
+    /// Typically this function is used only for hashing and debug information.
+    #[inline]
+    pub fn to_pointer(&self) -> *const c_void {
+        self.0.to_pointer()
+    }
+
+    /// Creates a deep clone of the Lua function.
+    ///
+    /// Copies the function prototype and all its upvalues to the
+    /// newly created function.
+    ///
+    /// This function returns shallow clone (same handle) for Rust/C functions.
+    /// Requires `feature = "luau"`
+    #[cfg(feature = "luau")]
+    #[cfg_attr(docsrs, doc(cfg(feature = "luau")))]
+    pub fn deep_clone(&self) -> Self {
+        let ref_thread = self.0.lua.ref_thread();
+        unsafe {
+            if ffi::lua_iscfunction(ref_thread, self.0.index) != 0 {
+                return self.clone();
+            }
+
+            ffi::lua_clonefunction(ref_thread, self.0.index);
+            Function(self.0.lua.pop_ref_thread())
+        }
+    }
+
     /// Convert this handle to owned version.
     #[cfg(all(feature = "unstable", any(not(feature = "send"), doc)))]
     #[cfg_attr(docsrs, doc(cfg(all(feature = "unstable", not(feature = "send")))))]

src/lua.rs

@@ -226,6 +226,7 @@ pub(crate) static EXTRA_REGISTRY_KEY: u8 = 0;
 
 const WRAPPED_FAILURE_POOL_SIZE: usize = 64;
 const MULTIVALUE_POOL_SIZE: usize = 64;
+const REF_STACK_RESERVE: c_int = 1;
 
 /// Requires `feature = "send"`
 #[cfg(feature = "send")]
@@ -519,8 +520,8 @@ impl Lua {
             #[cfg(feature = "module")]
             skip_memory_check: false,
             ref_thread,
-            // We need 1 extra stack space to move values in and out of the ref stack.
-            ref_stack_size: ffi::LUA_MINSTACK - 1,
+            // We need some reserved stack space to move values in and out of the ref stack.
+            ref_stack_size: ffi::LUA_MINSTACK - REF_STACK_RESERVE,
             ref_stack_top: ffi::lua_gettop(ref_thread),
             ref_free: Vec::new(),
             wrapped_failure_pool: Vec::with_capacity(WRAPPED_FAILURE_POOL_SIZE),
@@ -1372,6 +1373,27 @@ impl Lua {
         }
     }
 
+    /// Create and return a Luau [buffer] object from a byte slice of data.
+    ///
+    /// Requires `feature = "luau"`
+    ///
+    /// [buffer]: https://luau-lang.org/library#buffer-library
+    #[cfg(feature = "luau")]
+    pub fn create_buffer(&self, buf: impl AsRef<[u8]>) -> Result<AnyUserData> {
+        let state = self.state();
+        unsafe {
+            if self.unlikely_memory_error() {
+                crate::util::push_buffer(self.ref_thread(), buf.as_ref(), false)?;
+                return Ok(AnyUserData(self.pop_ref_thread(), SubtypeId::Buffer));
+            }
+
+            let _sg = StackGuard::new(state);
+            check_stack(state, 4)?;
+            crate::util::push_buffer(state, buf.as_ref(), true)?;
+            Ok(AnyUserData(self.pop_ref(), SubtypeId::Buffer))
+        }
+    }
+
     /// Creates and returns a new empty table.
     pub fn create_table(&self) -> Result<Table> {
         self.create_table_with_capacity(0, 0)
@@ -1413,8 +1435,8 @@ impl Lua {
             let protect = !self.unlikely_memory_error();
             push_table(state, 0, lower_bound, protect)?;
             for (k, v) in iter {
-                self.push_value(k.into_lua(self)?)?;
-                self.push_value(v.into_lua(self)?)?;
+                self.push(k)?;
+                self.push(v)?;
                 if protect {
                     protect_lua!(state, 3, 1, fn(state) ffi::lua_rawset(state, -3))?;
                 } else {
@@ -1442,7 +1464,7 @@ impl Lua {
             let protect = !self.unlikely_memory_error();
             push_table(state, lower_bound, 0, protect)?;
             for (i, v) in iter.enumerate() {
-                self.push_value(v.into_lua(self)?)?;
+                self.push(v)?;
                 if protect {
                     protect_lua!(state, 2, 1, |state| {
                         ffi::lua_rawseti(state, -2, (i + 1) as Integer);
@@ -1724,6 +1746,21 @@ impl Lua {
         unsafe { self.make_any_userdata(UserDataCell::new(data)) }
     }
 
+    /// Creates a Lua userdata object from a custom serializable Rust type.
+    ///
+    /// See [`Lua::create_any_userdata()`] for more details.
+    ///
+    /// Requires `feature = "serialize"`
+    #[cfg(feature = "serialize")]
+    #[cfg_attr(docsrs, doc(cfg(feature = "serialize")))]
+    #[inline]
+    pub fn create_ser_any_userdata<T>(&self, data: T) -> Result<AnyUserData>
+    where
+        T: Serialize + MaybeSend + 'static,
+    {
+        unsafe { self.make_any_userdata(UserDataCell::new_ser(data)) }
+    }
+
     /// Registers a custom Rust type in Lua to use in userdata objects.
     ///
     /// This methods provides a way to add fields or methods to userdata objects of a type `T`.
@@ -1977,12 +2014,11 @@ impl Lua {
         T: IntoLua<'lua>,
     {
         let state = self.state();
-        let t = t.into_lua(self)?;
         unsafe {
             let _sg = StackGuard::new(state);
             check_stack(state, 5)?;
 
-            self.push_value(t)?;
+            self.push(t)?;
             rawset_field(state, ffi::LUA_REGISTRYINDEX, name)
         }
     }
@@ -2269,33 +2305,38 @@ impl Lua {
         extra.app_data.remove()
     }
 
-    /// Pushes a value onto the Lua stack.
+    /// Pushes a value that implements `IntoLua` onto the Lua stack.
+    ///
+    /// Uses 2 stack spaces, does not call checkstack.
+    #[doc(hidden)]
+    #[inline(always)]
+    pub unsafe fn push<'lua>(&'lua self, value: impl IntoLua<'lua>) -> Result<()> {
+        value.push_into_stack(self)
+    }
+
+    /// Pushes a `Value` onto the Lua stack.
     ///
     /// Uses 2 stack spaces, does not call checkstack.
     #[doc(hidden)]
     pub unsafe fn push_value(&self, value: Value) -> Result<()> {
+        if let Value::Error(err) = value {
+            let protect = !self.unlikely_memory_error();
+            return push_gc_userdata(self.state(), WrappedFailure::Error(err), protect);
+        }
+        self.push_value_ref(&value)
+    }
+
+    /// Pushes a `&Value` (by reference) onto the Lua stack.
+    ///
+    /// Similar to [`Lua::push_value`], uses 2 stack spaces, does not call checkstack.
+    pub(crate) unsafe fn push_value_ref(&self, value: &Value) -> Result<()> {
         let state = self.state();
         match value {
-            Value::Nil => {
-                ffi::lua_pushnil(state);
-            }
-
-            Value::Boolean(b) => {
-                ffi::lua_pushboolean(state, b as c_int);
-            }
-
-            Value::LightUserData(ud) => {
-                ffi::lua_pushlightuserdata(state, ud.0);
-            }
-
-            Value::Integer(i) => {
-                ffi::lua_pushinteger(state, i);
-            }
-
-            Value::Number(n) => {
-                ffi::lua_pushnumber(state, n);
-            }
-
+            Value::Nil => ffi::lua_pushnil(state),
+            Value::Boolean(b) => ffi::lua_pushboolean(state, *b as c_int),
+            Value::LightUserData(ud) => ffi::lua_pushlightuserdata(state, ud.0),
+            Value::Integer(i) => ffi::lua_pushinteger(state, *i),
+            Value::Number(n) => ffi::lua_pushnumber(state, *n),
             #[cfg(feature = "luau")]
             Value::Vector(v) => {
                 #[cfg(not(feature = "luau-vector4"))]
@@ -2303,33 +2344,16 @@ impl Lua {
                 #[cfg(feature = "luau-vector4")]
                 ffi::lua_pushvector(state, v.x(), v.y(), v.z(), v.w());
             }
-
-            Value::String(s) => {
-                self.push_ref(&s.0);
-            }
-
-            Value::Table(t) => {
-                self.push_ref(&t.0);
-            }
-
-            Value::Function(f) => {
-                self.push_ref(&f.0);
-            }
-
-            Value::Thread(t) => {
-                self.push_ref(&t.0);
-            }
-
-            Value::UserData(ud) => {
-                self.push_ref(&ud.0);
-            }
-
+            Value::String(s) => self.push_ref(&s.0),
+            Value::Table(t) => self.push_ref(&t.0),
+            Value::Function(f) => self.push_ref(&f.0),
+            Value::Thread(t) => self.push_ref(&t.0),
+            Value::UserData(ud) => self.push_ref(&ud.0),
             Value::Error(err) => {
                 let protect = !self.unlikely_memory_error();
-                push_gc_userdata(state, WrappedFailure::Error(err), protect)?;
+                push_gc_userdata(state, WrappedFailure::Error(err.clone()), protect)?;
             }
         }
-
         Ok(())
     }
 
@@ -2643,12 +2667,12 @@ impl Lua {
         let metatable_nrec = metatable_nrec + registry.async_meta_methods.len();
         push_table(state, 0, metatable_nrec, true)?;
         for (k, m) in registry.meta_methods {
-            self.push_value(Value::Function(self.create_callback(m)?))?;
+            self.push(self.create_callback(m)?)?;
             rawset_field(state, -2, MetaMethod::validate(&k)?)?;
         }
         #[cfg(feature = "async")]
         for (k, m) in registry.async_meta_methods {
-            self.push_value(Value::Function(self.create_async_callback(m)?))?;
+            self.push(self.create_async_callback(m)?)?;
             rawset_field(state, -2, MetaMethod::validate(&k)?)?;
         }
         let mut has_name = false;
@@ -2699,7 +2723,7 @@ impl Lua {
         if field_getters_nrec > 0 {
             push_table(state, 0, field_getters_nrec, true)?;
             for (k, m) in registry.field_getters {
-                self.push_value(Value::Function(self.create_callback(m)?))?;
+                self.push(self.create_callback(m)?)?;
                 rawset_field(state, -2, &k)?;
             }
             field_getters_index = Some(ffi::lua_absindex(state, -1));
@@ -2711,7 +2735,7 @@ impl Lua {
         if field_setters_nrec > 0 {
             push_table(state, 0, field_setters_nrec, true)?;
             for (k, m) in registry.field_setters {
-                self.push_value(Value::Function(self.create_callback(m)?))?;
+                self.push(self.create_callback(m)?)?;
                 rawset_field(state, -2, &k)?;
             }
             field_setters_index = Some(ffi::lua_absindex(state, -1));
@@ -2734,12 +2758,12 @@ impl Lua {
                 }
             }
             for (k, m) in registry.methods {
-                self.push_value(Value::Function(self.create_callback(m)?))?;
+                self.push(self.create_callback(m)?)?;
                 rawset_field(state, -2, &k)?;
             }
             #[cfg(feature = "async")]
             for (k, m) in registry.async_methods {
-                self.push_value(Value::Function(self.create_async_callback(m)?))?;
+                self.push(self.create_async_callback(m)?)?;
                 rawset_field(state, -2, &k)?;
             }
             match index_type {
@@ -2990,7 +3014,7 @@ impl Lua {
                             nresults => {
                                 let results = MultiValue::from_stack_multi(nresults, lua)?;
                                 ffi::lua_pushinteger(state, nresults as _);
-                                lua.push_value(Value::Table(lua.create_sequence_from(results)?))?;
+                                lua.push(lua.create_sequence_from(results)?)?;
                                 Ok(2)
                             }
                         }

src/luau/package.rs

@@ -103,6 +103,7 @@ pub(crate) fn register_package_module(lua: &Lua) -> Result<()> {
     Ok(())
 }
 
+#[allow(unused_variables)]
 pub(crate) fn disable_dylibs(lua: &Lua) {
     // Presence of `LoadedDylibs` in app data is used as a flag
     // to check whether binary modules are enabled

src/multi.rs

@@ -1,4 +1,3 @@
-use std::iter::FromIterator;
 use std::ops::{Deref, DerefMut};
 use std::os::raw::c_int;
 use std::result::Result as StdResult;
@@ -23,6 +22,20 @@ impl<'lua, T: IntoLua<'lua>, E: IntoLua<'lua>> IntoLuaMulti<'lua> for StdResult<
         }
         Ok(result)
     }
+
+    #[inline]
+    unsafe fn push_into_stack_multi(self, lua: &'lua Lua) -> Result<c_int> {
+        match self {
+            Ok(v) => v.push_into_stack(lua).map(|_| 1),
+            Err(e) => {
+                let state = lua.state();
+                check_stack(state, 3)?;
+                ffi::lua_pushnil(state);
+                e.push_into_stack(lua)?;
+                Ok(2)
+            }
+        }
+    }
 }
 
 impl<'lua, E: IntoLua<'lua>> IntoLuaMulti<'lua> for StdResult<(), E> {
@@ -38,6 +51,20 @@ impl<'lua, E: IntoLua<'lua>> IntoLuaMulti<'lua> for StdResult<(), E> {
             }
         }
     }
+
+    #[inline]
+    unsafe fn push_into_stack_multi(self, lua: &'lua Lua) -> Result<c_int> {
+        match self {
+            Ok(_) => Ok(0),
+            Err(e) => {
+                let state = lua.state();
+                check_stack(state, 3)?;
+                ffi::lua_pushnil(state);
+                e.push_into_stack(lua)?;
+                Ok(2)
+            }
+        }
+    }
 }
 
 impl<'lua, T: IntoLua<'lua>> IntoLuaMulti<'lua> for T {

src/scope.rs

@@ -19,7 +19,7 @@ use crate::util::{
     self, assert_stack, check_stack, init_userdata_metatable, push_string, push_table,
     rawset_field, short_type_name, take_userdata, StackGuard,
 };
-use crate::value::{FromLua, FromLuaMulti, IntoLua, IntoLuaMulti, Value};
+use crate::value::{FromLua, FromLuaMulti, IntoLua, IntoLuaMulti};
 
 #[cfg(feature = "lua54")]
 use crate::userdata::USER_VALUE_MAXSLOT;
@@ -405,7 +405,7 @@ impl<'lua, 'scope> Scope<'lua, 'scope> {
             let meta_methods_nrec = registry.meta_methods.len() + registry.meta_fields.len() + 1;
             push_table(state, 0, meta_methods_nrec, true)?;
             for (k, m) in registry.meta_methods {
-                lua.push_value(Value::Function(wrap_method(self, ud_ptr, &k, m)?))?;
+                lua.push(wrap_method(self, ud_ptr, &k, m)?)?;
                 rawset_field(state, -2, MetaMethod::validate(&k)?)?;
             }
             let mut has_name = false;
@@ -455,7 +455,7 @@ impl<'lua, 'scope> Scope<'lua, 'scope> {
             if field_getters_nrec > 0 {
                 push_table(state, 0, field_getters_nrec, true)?;
                 for (k, m) in registry.field_getters {
-                    lua.push_value(Value::Function(wrap_method(self, ud_ptr, &k, m)?))?;
+                    lua.push(wrap_method(self, ud_ptr, &k, m)?)?;
                     rawset_field(state, -2, &k)?;
                 }
                 field_getters_index = Some(ffi::lua_absindex(state, -1));
@@ -466,7 +466,7 @@ impl<'lua, 'scope> Scope<'lua, 'scope> {
             if field_setters_nrec > 0 {
                 push_table(state, 0, field_setters_nrec, true)?;
                 for (k, m) in registry.field_setters {
-                    lua.push_value(Value::Function(wrap_method(self, ud_ptr, &k, m)?))?;
+                    lua.push(wrap_method(self, ud_ptr, &k, m)?)?;
                     rawset_field(state, -2, &k)?;
                 }
                 field_setters_index = Some(ffi::lua_absindex(state, -1));
@@ -478,7 +478,7 @@ impl<'lua, 'scope> Scope<'lua, 'scope> {
                 // Create table used for methods lookup
                 push_table(state, 0, methods_nrec, true)?;
                 for (k, m) in registry.methods {
-                    lua.push_value(Value::Function(wrap_method(self, ud_ptr, &k, m)?))?;
+                    lua.push(wrap_method(self, ud_ptr, &k, m)?)?;
                     rawset_field(state, -2, &k)?;
                 }
                 methods_index = Some(ffi::lua_absindex(state, -1));

src/serde/de.rs

@@ -1,5 +1,4 @@
 use std::cell::RefCell;
-use std::convert::TryInto;
 use std::os::raw::c_void;
 use std::rc::Rc;
 use std::result::Result as StdResult;
@@ -134,9 +133,7 @@ impl<'lua, 'de> serde::Deserializer<'de> for Deserializer<'lua> {
             Value::Nil => visitor.visit_unit(),
             Value::Boolean(b) => visitor.visit_bool(b),
             #[allow(clippy::useless_conversion)]
-            Value::Integer(i) => {
-                visitor.visit_i64(i.try_into().expect("cannot convert lua_Integer to i64"))
-            }
+            Value::Integer(i) => visitor.visit_i64(i.into()),
             #[allow(clippy::useless_conversion)]
             Value::Number(n) => visitor.visit_f64(n.into()),
             #[cfg(feature = "luau")]
@@ -151,6 +148,14 @@ impl<'lua, 'de> serde::Deserializer<'de> for Deserializer<'lua> {
             Value::UserData(ud) if ud.is_serializable() => {
                 serde_userdata(ud, |value| value.deserialize_any(visitor))
             }
+            #[cfg(feature = "luau")]
+            Value::UserData(ud) if ud.1 == crate::types::SubtypeId::Buffer => unsafe {
+                let mut size = 0usize;
+                let buf = ffi::lua_tobuffer(ud.0.lua.ref_thread(), ud.0.index, &mut size);
+                mlua_assert!(!buf.is_null(), "invalid Luau buffer");
+                let buf = std::slice::from_raw_parts(buf as *const u8, size);
+                visitor.visit_bytes(buf)
+            },
             Value::Function(_)
             | Value::Thread(_)
             | Value::UserData(_)

src/serde/ser.rs

@@ -3,7 +3,6 @@ use serde::{ser, Serialize};
 use super::LuaSerdeExt;
 use crate::error::{Error, Result};
 use crate::lua::Lua;
-use crate::string::String;
 use crate::table::Table;
 use crate::value::{IntoLua, Value};
 
@@ -43,6 +42,12 @@ pub struct Options {
     /// [`null`]: crate::LuaSerdeExt::null
     /// [`Nil`]: crate::Value::Nil
     pub serialize_unit_to_null: bool,
+
+    /// If true, serialize `serde_json::Number` with arbitrary_precision to a Lua number.
+    /// Otherwise it will be serialized as an object (what serde does).
+    ///
+    /// Default: **false**
+    pub detect_serde_json_arbitrary_precision: bool,
 }
 
 impl Default for Options {
@@ -58,6 +63,7 @@ impl Options {
             set_array_metatable: true,
             serialize_none_to_null: true,
             serialize_unit_to_null: true,
+            detect_serde_json_arbitrary_precision: false,
         }
     }
 
@@ -87,6 +93,20 @@ impl Options {
         self.serialize_unit_to_null = enabled;
         self
     }
+
+    /// Sets [`detect_serde_json_arbitrary_precision`] option.
+    ///
+    /// This option is used to serialize `serde_json::Number` with arbitrary precision to a Lua number.
+    /// Otherwise it will be serialized as an object (what serde does).
+    ///
+    /// This option is disabled by default.
+    ///
+    /// [`detect_serde_json_arbitrary_precision`]: #structfield.detect_serde_json_arbitrary_precision
+    #[must_use]
+    pub const fn detect_serde_json_arbitrary_precision(mut self, enabled: bool) -> Self {
+        self.detect_serde_json_arbitrary_precision = enabled;
+        self
+    }
 }
 
 impl<'lua> Serializer<'lua> {
@@ -121,7 +141,7 @@ impl<'lua> ser::Serializer for Serializer<'lua> {
     type SerializeTupleStruct = SerializeSeq<'lua>;
     type SerializeTupleVariant = SerializeTupleVariant<'lua>;
     type SerializeMap = SerializeMap<'lua>;
-    type SerializeStruct = SerializeMap<'lua>;
+    type SerializeStruct = SerializeStruct<'lua>;
     type SerializeStructVariant = SerializeStructVariant<'lua>;
 
     #[inline]
@@ -266,7 +286,7 @@ impl<'lua> ser::Serializer for Serializer<'lua> {
         _len: usize,
     ) -> Result<Self::SerializeTupleVariant> {
         Ok(SerializeTupleVariant {
-            name: self.lua.create_string(variant)?,
+            variant,
             table: self.lua.create_table()?,
             options: self.options,
         })
@@ -282,8 +302,23 @@ impl<'lua> ser::Serializer for Serializer<'lua> {
     }
 
     #[inline]
-    fn serialize_struct(self, _name: &'static str, len: usize) -> Result<Self::SerializeStruct> {
-        self.serialize_map(Some(len))
+    fn serialize_struct(self, name: &'static str, len: usize) -> Result<Self::SerializeStruct> {
+        if self.options.detect_serde_json_arbitrary_precision
+            && name == "$serde_json::private::Number"
+            && len == 1
+        {
+            return Ok(SerializeStruct {
+                lua: self.lua,
+                inner: None,
+                options: self.options,
+            });
+        }
+
+        Ok(SerializeStruct {
+            lua: self.lua,
+            inner: Some(Value::Table(self.lua.create_table_with_capacity(0, len)?)),
+            options: self.options,
+        })
     }
 
     #[inline]
@@ -295,7 +330,7 @@ impl<'lua> ser::Serializer for Serializer<'lua> {
         len: usize,
     ) -> Result<Self::SerializeStructVariant> {
         Ok(SerializeStructVariant {
-            name: self.lua.create_string(variant)?,
+            variant,
             table: self.lua.create_table_with_capacity(0, len)?,
             options: self.options,
         })
@@ -402,7 +437,7 @@ impl<'lua> ser::SerializeTupleStruct for SerializeSeq<'lua> {
 
 #[doc(hidden)]
 pub struct SerializeTupleVariant<'lua> {
-    name: String<'lua>,
+    variant: &'static str,
     table: Table<'lua>,
     options: Options,
 }
@@ -422,7 +457,7 @@ impl<'lua> ser::SerializeTupleVariant for SerializeTupleVariant<'lua> {
     fn end(self) -> Result<Value<'lua>> {
         let lua = self.table.0.lua;
         let table = lua.create_table()?;
-        table.raw_set(self.name, self.table)?;
+        table.raw_set(self.variant, self.table)?;
         Ok(Value::Table(table))
     }
 }
@@ -465,7 +500,14 @@ impl<'lua> ser::SerializeMap for SerializeMap<'lua> {
     }
 }
 
-impl<'lua> ser::SerializeStruct for SerializeMap<'lua> {
+#[doc(hidden)]
+pub struct SerializeStruct<'lua> {
+    lua: &'lua Lua,
+    inner: Option<Value<'lua>>,
+    options: Options,
+}
+
+impl<'lua> ser::SerializeStruct for SerializeStruct<'lua> {
     type Ok = Value<'lua>;
     type Error = Error;
 
@@ -473,18 +515,44 @@ impl<'lua> ser::SerializeStruct for SerializeMap<'lua> {
     where
         T: Serialize + ?Sized,
     {
-        ser::SerializeMap::serialize_key(self, key)?;
-        ser::SerializeMap::serialize_value(self, value)
+        match self.inner {
+            Some(Value::Table(ref table)) => {
+                table.raw_set(key, self.lua.to_value_with(value, self.options)?)?;
+            }
+            None if self.options.detect_serde_json_arbitrary_precision => {
+                // A special case for `serde_json::Number` with arbitrary precision.
+                assert_eq!(key, "$serde_json::private::Number");
+                self.inner = Some(self.lua.to_value_with(value, self.options)?);
+            }
+            _ => unreachable!(),
+        }
+        Ok(())
     }
 
     fn end(self) -> Result<Value<'lua>> {
-        ser::SerializeMap::end(self)
+        match self.inner {
+            Some(table @ Value::Table(_)) => Ok(table),
+            Some(value) if self.options.detect_serde_json_arbitrary_precision => {
+                let number_s = value.as_str().expect("not an arbitrary precision number");
+                if number_s.contains(['.', 'e', 'E']) {
+                    if let Ok(number) = number_s.parse().map(Value::Number) {
+                        return Ok(number);
+                    }
+                }
+                Ok(number_s
+                    .parse()
+                    .map(Value::Integer)
+                    .or_else(|_| number_s.parse().map(Value::Number))
+                    .unwrap_or(value))
+            }
+            _ => unreachable!(),
+        }
     }
 }
 
 #[doc(hidden)]
 pub struct SerializeStructVariant<'lua> {
-    name: String<'lua>,
+    variant: &'static str,
     table: Table<'lua>,
     options: Options,
 }
@@ -505,8 +573,8 @@ impl<'lua> ser::SerializeStructVariant for SerializeStructVariant<'lua> {
 
     fn end(self) -> Result<Value<'lua>> {
         let lua = self.table.0.lua;
-        let table = lua.create_table()?;
-        table.raw_set(self.name, self.table)?;
+        let table = lua.create_table_with_capacity(0, 1)?;
+        table.raw_set(self.variant, self.table)?;
         Ok(Value::Table(table))
     }
 }

src/string.rs

@@ -132,7 +132,7 @@ impl<'lua> String<'lua> {
         }
     }
 
-    /// Converts the string to a generic C pointer.
+    /// Converts this string to a generic C pointer.
     ///
     /// There is no way to convert the pointer back to its original value.
     ///

src/table.rs

@@ -591,7 +591,7 @@ impl<'lua> Table<'lua> {
         unsafe { ffi::lua_getreadonly(ref_thread, self.0.index) != 0 }
     }
 
-    /// Converts the table to a generic C pointer.
+    /// Converts this table to a generic C pointer.
     ///
     /// Different tables will give different pointers.
     /// There is no way to convert the pointer back to its original value.
@@ -721,7 +721,6 @@ impl<'lua> Table<'lua> {
         TableSequence {
             table: self.0,
             index: 1,
-            len: None,
             _phantom: PhantomData,
         }
     }
@@ -733,17 +732,25 @@ impl<'lua> Table<'lua> {
     }
 
     #[cfg(feature = "serialize")]
-    pub(crate) fn sequence_values_by_len<V: FromLua<'lua>>(
-        self,
-        len: Option<usize>,
-    ) -> TableSequence<'lua, V> {
-        let len = len.unwrap_or_else(|| self.raw_len()) as Integer;
-        TableSequence {
-            table: self.0,
-            index: 1,
-            len: Some(len),
-            _phantom: PhantomData,
+    pub(crate) fn for_each_value<V>(&self, mut f: impl FnMut(V) -> Result<()>) -> Result<()>
+    where
+        V: FromLua<'lua>,
+    {
+        let lua = self.0.lua;
+        let state = lua.state();
+        unsafe {
+            let _sg = StackGuard::new(state);
+            check_stack(state, 4)?;
+
+            lua.push_ref(&self.0);
+            let len = ffi::lua_rawlen(state, -1);
+            for i in 1..=len {
+                ffi::lua_rawgeti(state, -1, i as _);
+                f(V::from_stack(-1, lua)?)?;
+                ffi::lua_pop(state, 1);
+            }
         }
+        Ok(())
     }
 
     /// Sets element value at position `idx` without invoking metamethods.
@@ -1085,6 +1092,13 @@ impl<'a, 'lua> Serialize for SerializableTable<'a, 'lua> {
         use crate::serde::de::{check_value_for_skip, MapPairs};
         use crate::value::SerializableValue;
 
+        let convert_result = |res: Result<()>, serialize_err: Option<S::Error>| match res {
+            Ok(v) => Ok(v),
+            Err(Error::SerializeError(_)) if serialize_err.is_some() => Err(serialize_err.unwrap()),
+            Err(Error::SerializeError(msg)) => Err(serde::ser::Error::custom(msg)),
+            Err(err) => Err(serde::ser::Error::custom(err.to_string())),
+        };
+
         let options = self.options;
         let visited = &self.visited;
         visited.borrow_mut().insert(self.table.to_pointer());
@@ -1093,15 +1107,21 @@ impl<'a, 'lua> Serialize for SerializableTable<'a, 'lua> {
         let len = self.table.raw_len();
         if len > 0 || self.table.is_array() {
             let mut seq = serializer.serialize_seq(Some(len))?;
-            for value in self.table.clone().sequence_values_by_len::<Value>(None) {
-                let value = &value.map_err(serde::ser::Error::custom)?;
-                let skip = check_value_for_skip(value, self.options, &self.visited)
-                    .map_err(serde::ser::Error::custom)?;
+            let mut serialize_err = None;
+            let res = self.table.for_each_value::<Value>(|value| {
+                let skip = check_value_for_skip(&value, self.options, &self.visited)
+                    .map_err(|err| Error::SerializeError(err.to_string()))?;
                 if skip {
-                    continue;
+                    // continue iteration
+                    return Ok(());
                 }
-                seq.serialize_element(&SerializableValue::new(value, options, Some(visited)))?;
-            }
+                seq.serialize_element(&SerializableValue::new(&value, options, Some(visited)))
+                    .map_err(|err| {
+                        serialize_err = Some(err);
+                        Error::SerializeError(String::new())
+                    })
+            });
+            convert_result(res, serialize_err)?;
             return seq.end();
         }
 
@@ -1138,18 +1158,7 @@ impl<'a, 'lua> Serialize for SerializableTable<'a, 'lua> {
                     process_pair(key, value)
                 })
         };
-        match res {
-            Ok(_) => {}
-            Err(Error::SerializeError(_)) if serialize_err.is_some() => {
-                return Err(serialize_err.unwrap());
-            }
-            Err(Error::SerializeError(msg)) => {
-                return Err(serde::ser::Error::custom(msg));
-            }
-            Err(err) => {
-                return Err(serde::ser::Error::custom(err.to_string()));
-            }
-        }
+        convert_result(res, serialize_err)?;
         map.end()
     }
 }
@@ -1219,9 +1228,9 @@ where
 ///
 /// [`Table::sequence_values`]: crate::Table::sequence_values
 pub struct TableSequence<'lua, V> {
+    // TODO: Use `&Table`
     table: LuaRef<'lua>,
     index: Integer,
-    len: Option<Integer>,
     _phantom: PhantomData<V>,
 }
 
@@ -1242,7 +1251,7 @@ where
 
             lua.push_ref(&self.table);
             match ffi::lua_rawgeti(state, -1, self.index) {
-                ffi::LUA_TNIL if self.index > self.len.unwrap_or(0) => None,
+                ffi::LUA_TNIL => None,
                 _ => {
                     self.index += 1;
                     Some(V::from_stack(-1, lua))

src/thread.rs

@@ -1,4 +1,4 @@
-use std::os::raw::c_int;
+use std::os::raw::{c_int, c_void};
 
 use crate::error::{Error, Result};
 #[allow(unused)]
@@ -375,6 +375,16 @@ impl<'lua> Thread<'lua> {
         }
     }
 
+    /// Converts this thread to a generic C pointer.
+    ///
+    /// There is no way to convert the pointer back to its original value.
+    ///
+    /// Typically this function is used only for hashing and debug information.
+    #[inline]
+    pub fn to_pointer(&self) -> *const c_void {
+        self.0.to_pointer()
+    }
+
     /// Convert this handle to owned version.
     #[cfg(all(feature = "unstable", any(not(feature = "send"), doc)))]
     #[cfg_attr(docsrs, doc(cfg(all(feature = "unstable", not(feature = "send")))))]

src/userdata.rs

@@ -5,7 +5,7 @@ use std::fmt;
 use std::hash::Hash;
 use std::mem;
 use std::ops::{Deref, DerefMut};
-use std::os::raw::{c_char, c_int};
+use std::os::raw::{c_char, c_int, c_void};
 use std::string::String as StdString;
 
 #[cfg(feature = "async")]
@@ -54,8 +54,8 @@ pub enum MetaMethod {
     /// The unary minus (`-`) operator.
     Unm,
     /// The floor division (//) operator.
-    /// Requires `feature = "lua54/lua53"`
-    #[cfg(any(feature = "lua54", feature = "lua53"))]
+    /// Requires `feature = "lua54/lua53/luau"`
+    #[cfg(any(feature = "lua54", feature = "lua53", feature = "luau"))]
     IDiv,
     /// The bitwise AND (&) operator.
     /// Requires `feature = "lua54/lua53"`
@@ -180,7 +180,7 @@ impl MetaMethod {
             MetaMethod::Pow => "__pow",
             MetaMethod::Unm => "__unm",
 
-            #[cfg(any(feature = "lua54", feature = "lua53"))]
+            #[cfg(any(feature = "lua54", feature = "lua53", feature = "luau"))]
             MetaMethod::IDiv => "__idiv",
             #[cfg(any(feature = "lua54", feature = "lua53"))]
             MetaMethod::BAnd => "__band",
@@ -815,11 +815,7 @@ impl OwnedAnyUserData {
 impl<'lua> AnyUserData<'lua> {
     /// Checks whether the type of this userdata is `T`.
     pub fn is<T: 'static>(&self) -> bool {
-        match self.inspect(|_: &UserDataCell<T>| Ok(())) {
-            Ok(()) => true,
-            Err(Error::UserDataTypeMismatch) => false,
-            Err(_) => unreachable!(),
-        }
+        self.inspect(|_: &UserDataCell<T>| Ok(())).is_ok()
     }
 
     /// Borrow this userdata immutably if it is of type `T`.
@@ -919,7 +915,7 @@ impl<'lua> AnyUserData<'lua> {
             check_stack(state, 5)?;
 
             lua.push_userdata_ref(&self.0)?;
-            lua.push_value(v.into_lua(lua)?)?;
+            lua.push(v)?;
 
             #[cfg(feature = "lua54")]
             if n < USER_VALUE_MAXSLOT {
@@ -1014,7 +1010,7 @@ impl<'lua> AnyUserData<'lua> {
             check_stack(state, 5)?;
 
             lua.push_userdata_ref(&self.0)?;
-            lua.push_value(v.into_lua(lua)?)?;
+            lua.push(v)?;
 
             // Multiple (extra) user values are emulated by storing them in a table
             protect_lua!(state, 2, 0, |state| {
@@ -1096,6 +1092,16 @@ impl<'lua> AnyUserData<'lua> {
         }
     }
 
+    /// Converts this userdata to a generic C pointer.
+    ///
+    /// There is no way to convert the pointer back to its original value.
+    ///
+    /// Typically this function is used only for hashing and debug information.
+    #[inline]
+    pub fn to_pointer(&self) -> *const c_void {
+        self.0.to_pointer()
+    }
+
     /// Convert this handle to owned version.
     #[cfg(all(feature = "unstable", any(not(feature = "send"), doc)))]
     #[cfg_attr(docsrs, doc(cfg(all(feature = "unstable", not(feature = "send")))))]
@@ -1334,6 +1340,19 @@ impl<'lua> Serialize for AnyUserData<'lua> {
         S: Serializer,
     {
         let lua = self.0.lua;
+
+        // Special case for Luau buffer type
+        #[cfg(feature = "luau")]
+        if self.1 == SubtypeId::Buffer {
+            let buf = unsafe {
+                let mut size = 0usize;
+                let buf = ffi::lua_tobuffer(lua.ref_thread(), self.0.index, &mut size);
+                mlua_assert!(!buf.is_null(), "invalid Luau buffer");
+                std::slice::from_raw_parts(buf as *const u8, size)
+            };
+            return serializer.serialize_bytes(buf);
+        }
+
         let data = unsafe {
             let _ = lua
                 .get_userdata_ref_type_id(&self.0)
@@ -1352,7 +1371,7 @@ impl<'lua> Serialize for AnyUserData<'lua> {
 /// A wrapper type for an immutably borrowed value from a `AnyUserData`.
 ///
 /// It implements [`FromLua`] and can be used to receive a typed userdata from Lua.
-pub struct UserDataRef<'lua, T: 'static>(AnyUserData<'lua>, Ref<'lua, T>);
+pub struct UserDataRef<'lua, T: 'static>(#[allow(unused)] AnyUserData<'lua>, Ref<'lua, T>);
 
 impl<'lua, T: 'static> Deref for UserDataRef<'lua, T> {
     type Target = T;
@@ -1374,7 +1393,7 @@ impl<'lua, T: 'static> UserDataRef<'lua, T> {
 /// A wrapper type for a mutably borrowed value from a `AnyUserData`.
 ///
 /// It implements [`FromLua`] and can be used to receive a typed userdata from Lua.
-pub struct UserDataRefMut<'lua, T: 'static>(AnyUserData<'lua>, RefMut<'lua, T>);
+pub struct UserDataRefMut<'lua, T: 'static>(#[allow(unused)] AnyUserData<'lua>, RefMut<'lua, T>);
 
 impl<'lua, T: 'static> Deref for UserDataRefMut<'lua, T> {
     type Target = T;

src/util/mod.rs

@@ -253,6 +253,20 @@ pub unsafe fn push_string(state: *mut ffi::lua_State, s: &[u8], protect: bool) -
     }
 }
 
+// Uses 3 stack spaces (when protect), does not call checkstack.
+#[cfg(feature = "luau")]
+#[inline(always)]
+pub unsafe fn push_buffer(state: *mut ffi::lua_State, b: &[u8], protect: bool) -> Result<()> {
+    let data = if protect {
+        protect_lua!(state, 0, 1, |state| ffi::lua_newbuffer(state, b.len()))?
+    } else {
+        ffi::lua_newbuffer(state, b.len())
+    };
+    let buf = slice::from_raw_parts_mut(data as *mut u8, b.len());
+    buf.copy_from_slice(b);
+    Ok(())
+}
+
 // Uses 3 stack spaces, does not call checkstack.
 #[inline]
 pub unsafe fn push_table(
@@ -928,7 +942,7 @@ pub unsafe fn init_error_registry(state: *mut ffi::lua_State) -> Result<()> {
         "__mod",
         "__pow",
         "__unm",
-        #[cfg(any(feature = "lua54", feature = "lua53"))]
+        #[cfg(any(feature = "lua54", feature = "lua53", feature = "luau"))]
         "__idiv",
         #[cfg(any(feature = "lua54", feature = "lua53"))]
         "__band",
@@ -1045,6 +1059,8 @@ pub(crate) unsafe fn to_string(state: *mut ffi::lua_State, index: c_int) -> Stri
         ffi::LUA_TTHREAD => format!("<thread {:?}>", ffi::lua_topointer(state, index)),
         #[cfg(feature = "luau")]
         ffi::LUA_TBUFFER => format!("<buffer {:?}>", ffi::lua_topointer(state, index)),
+        #[cfg(feature = "luajit")]
+        ffi::LUA_TCDATA => format!("<cdata {:?}>", ffi::lua_topointer(state, index)),
         _ => "<unknown>".to_string(),
     }
 }

src/value.rs

@@ -1,7 +1,7 @@
 use std::borrow::Cow;
 use std::cmp::Ordering;
 use std::collections::HashSet;
-use std::iter::{self, FromIterator};
+use std::iter;
 use std::ops::Index;
 use std::os::raw::{c_int, c_void};
 use std::string::String as StdString;
@@ -15,7 +15,7 @@ use {
     crate::table::SerializableTable,
     rustc_hash::FxHashSet,
     serde::ser::{self, Serialize, Serializer},
-    std::{cell::RefCell, convert::TryInto, rc::Rc, result::Result as StdResult},
+    std::{cell::RefCell, rc::Rc, result::Result as StdResult},
 };
 
 use crate::error::{Error, Result};
@@ -252,8 +252,7 @@ impl<'lua> Value<'lua> {
     /// If the value is a Lua [`Integer`], try to convert it to `i64` or return `None` otherwise.
     #[inline]
     pub fn as_i64(&self) -> Option<i64> {
-        #[allow(clippy::useless_conversion)]
-        self.as_integer().and_then(|i| i64::try_from(i).ok())
+        self.as_integer().map(i64::from)
     }
 
     /// Cast the value to `u64`.
@@ -659,8 +658,7 @@ impl<'a, 'lua> Serialize for SerializableValue<'a, 'lua> {
             Value::Nil => serializer.serialize_unit(),
             Value::Boolean(b) => serializer.serialize_bool(*b),
             #[allow(clippy::useless_conversion)]
-            Value::Integer(i) => serializer
-                .serialize_i64((*i).try_into().expect("cannot convert Lua Integer to i64")),
+            Value::Integer(i) => serializer.serialize_i64((*i).into()),
             Value::Number(n) => serializer.serialize_f64(*n),
             #[cfg(feature = "luau")]
             Value::Vector(v) => v.serialize(serializer),

tests/conversion.rs

@@ -2,8 +2,29 @@ use std::borrow::Cow;
 use std::collections::{BTreeMap, BTreeSet, HashMap, HashSet};
 use std::ffi::{CStr, CString};
 
+use bstr::BString;
 use maplit::{btreemap, btreeset, hashmap, hashset};
-use mlua::{AnyUserData, Error, Function, IntoLua, Lua, Result, Table, Thread, UserDataRef, Value};
+use mlua::{
+    AnyUserData, Error, Function, IntoLua, Lua, RegistryKey, Result, Table, Thread, UserDataRef,
+    Value,
+};
+
+#[test]
+fn test_value_into_lua() -> Result<()> {
+    let lua = Lua::new();
+
+    // Direct conversion
+    let v = Value::Boolean(true);
+    let v2 = (&v).into_lua(&lua)?;
+    assert_eq!(v, v2);
+
+    // Push into stack
+    let table = lua.create_table()?;
+    table.set("v", &v)?;
+    assert_eq!(v, table.get::<_, Value>("v")?);
+
+    Ok(())
+}
 
 #[test]
 fn test_string_into_lua() -> Result<()> {
@@ -212,14 +233,22 @@ fn test_owned_anyuserdata_into_lua() -> Result<()> {
 fn test_registry_value_into_lua() -> Result<()> {
     let lua = Lua::new();
 
-    let t = lua.create_table()?;
-    let r = lua.create_registry_value(t)?;
-    let f = lua.create_function(|_, t: Table| t.raw_set("hello", "world"))?;
+    // Direct conversion
+    let s = lua.create_string("hello, world")?;
+    let r = lua.create_registry_value(&s)?;
+    let value1 = lua.pack(&r)?;
+    let value2 = lua.pack(r)?;
+    assert_eq!(value1.as_str(), Some("hello, world"));
+    assert_eq!(value2.to_pointer(), value2.to_pointer());
 
-    f.call(&r)?;
-    let v = r.into_lua(&lua)?;
-    let t = v.as_table().unwrap();
+    // Push into stack
+    let t = lua.create_table()?;
+    let r = lua.create_registry_value(&t)?;
+    let f = lua.create_function(|_, (t, k, v): (Table, Value, Value)| t.set(k, v))?;
+    f.call((&r, "hello", "world"))?;
+    f.call((r, "welcome", "to the jungle"))?;
     assert_eq!(t.get::<_, String>("hello")?, "world");
+    assert_eq!(t.get::<_, String>("welcome")?, "to the jungle");
 
     // Try to set nil registry key
     let r_nil = lua.create_registry_value(Value::Nil)?;
@@ -237,6 +266,17 @@ fn test_registry_value_into_lua() -> Result<()> {
     Ok(())
 }
 
+#[test]
+fn test_registry_key_from_lua() -> Result<()> {
+    let lua = Lua::new();
+
+    let fkey = lua.load("function() return 1 end").eval::<RegistryKey>()?;
+    let f = lua.registry_value::<Function>(&fkey)?;
+    assert_eq!(f.call::<_, i32>(())?, 1);
+
+    Ok(())
+}
+
 #[test]
 fn test_conv_vec() -> Result<()> {
     let lua = Lua::new();
@@ -370,3 +410,64 @@ fn test_conv_array() -> Result<()> {
 
     Ok(())
 }
+
+#[test]
+fn test_bstring_from_lua() -> Result<()> {
+    let lua = Lua::new();
+
+    let s = lua.create_string("hello, world")?;
+    let bstr = lua.unpack::<BString>(Value::String(s))?;
+    assert_eq!(bstr, "hello, world");
+
+    let bstr = lua.unpack::<BString>(Value::Integer(123))?;
+    assert_eq!(bstr, "123");
+
+    let bstr = lua.unpack::<BString>(Value::Number(-123.55))?;
+    assert_eq!(bstr, "-123.55");
+
+    // Test from stack
+    let f = lua.create_function(|_, bstr: BString| Ok(bstr))?;
+    let bstr = f.call::<_, BString>("hello, world")?;
+    assert_eq!(bstr, "hello, world");
+
+    let bstr = f.call::<_, BString>(-43.22)?;
+    assert_eq!(bstr, "-43.22");
+
+    Ok(())
+}
+
+#[cfg(feature = "luau")]
+#[test]
+fn test_bstring_from_lua_buffer() -> Result<()> {
+    let lua = Lua::new();
+
+    let b = lua.create_buffer("hello, world")?;
+    let bstr = lua.unpack::<BString>(Value::UserData(b))?;
+    assert_eq!(bstr, "hello, world");
+
+    // Test from stack
+    let f = lua.create_function(|_, bstr: BString| Ok(bstr))?;
+    let buf = lua.create_buffer("hello, world")?;
+    let bstr = f.call::<_, BString>(buf)?;
+    assert_eq!(bstr, "hello, world");
+
+    Ok(())
+}
+
+#[test]
+fn test_option_into_from_lua() -> Result<()> {
+    let lua = Lua::new();
+
+    // Direct conversion
+    let v = Some(42);
+    let v2 = v.into_lua(&lua)?;
+    assert_eq!(v, v2.as_i32());
+
+    // Push into stack / get from stack
+    let f = lua.create_function(|_, v: Option<i32>| Ok(v))?;
+    assert_eq!(f.call::<_, Option<i32>>(Some(42))?, Some(42));
+    assert_eq!(f.call::<_, Option<i32>>(Option::<i32>::None)?, None);
+    assert_eq!(f.call::<_, Option<i32>>(())?, None);
+
+    Ok(())
+}

tests/function.rs

@@ -231,6 +231,40 @@ fn test_function_info() -> Result<()> {
     Ok(())
 }
 
+#[test]
+fn test_function_pointer() -> Result<()> {
+    let lua = Lua::new();
+
+    let func1 = lua.load("return function() end").into_function()?;
+    let func2 = func1.call::<_, Function>(())?;
+
+    assert_eq!(func1.to_pointer(), func1.clone().to_pointer());
+    assert_ne!(func1.to_pointer(), func2.to_pointer());
+
+    Ok(())
+}
+
+#[cfg(feature = "luau")]
+#[test]
+fn test_function_deep_clone() -> Result<()> {
+    let lua = Lua::new();
+
+    lua.globals().set("a", 1)?;
+    let func1 = lua.load("a += 1; return a").into_function()?;
+    let func2 = func1.deep_clone();
+
+    assert_ne!(func1.to_pointer(), func2.to_pointer());
+    assert_eq!(func1.call::<_, i32>(())?, 2);
+    assert_eq!(func2.call::<_, i32>(())?, 3);
+
+    // Check that for Rust functions deep_clone is just a clone
+    let rust_func = lua.create_function(|_, ()| Ok(42))?;
+    let rust_func2 = rust_func.deep_clone();
+    assert_eq!(rust_func.to_pointer(), rust_func2.to_pointer());
+
+    Ok(())
+}
+
 #[test]
 fn test_function_wrap() -> Result<()> {
     use mlua::Error;

tests/luau.rs

@@ -275,6 +275,22 @@ fn test_sandbox() -> Result<()> {
     Ok(())
 }
 
+#[test]
+fn test_sandbox_nolibs() -> Result<()> {
+    let lua = Lua::new_with(StdLib::NONE, LuaOptions::default()).unwrap();
+
+    lua.sandbox(true)?;
+    lua.load("global = 123").exec()?;
+    let n: i32 = lua.load("return global").eval()?;
+    assert_eq!(n, 123);
+    assert_eq!(lua.globals().get::<_, Option<i32>>("global")?, Some(123));
+
+    lua.sandbox(false)?;
+    assert_eq!(lua.globals().get::<_, Option<i32>>("global")?, None);
+
+    Ok(())
+}
+
 #[test]
 fn test_sandbox_threads() -> Result<()> {
     let lua = Lua::new();

tests/memory.rs

@@ -84,7 +84,7 @@ fn test_gc_control() -> Result<()> {
 
     assert_eq!(lua.gc_inc(200, 100, 13), GCMode::Incremental);
 
-    struct MyUserdata(Arc<()>);
+    struct MyUserdata(#[allow(unused)] Arc<()>);
     impl UserData for MyUserdata {}
 
     let rc = Arc::new(());

tests/multi.rs

@@ -0,0 +1,60 @@
+use mlua::{Error, ExternalError, IntoLuaMulti, Lua, Result, String, Value};
+
+#[test]
+fn test_result_conversions() -> Result<()> {
+    let lua = Lua::new();
+    let globals = lua.globals();
+
+    let ok = lua.create_function(|_, ()| Ok(Ok::<(), Error>(())))?;
+    let err = lua.create_function(|_, ()| Ok(Err::<(), _>("failure1".into_lua_err())))?;
+    let ok2 = lua.create_function(|_, ()| Ok(Ok::<_, Error>("!".to_owned())))?;
+    let err2 = lua.create_function(|_, ()| Ok(Err::<String, _>("failure2".into_lua_err())))?;
+
+    globals.set("ok", ok)?;
+    globals.set("ok2", ok2)?;
+    globals.set("err", err)?;
+    globals.set("err2", err2)?;
+
+    lua.load(
+        r#"
+        local r, e = ok()
+        assert(r == nil and e == nil)
+
+        local r, e = err()
+        assert(r == nil)
+        assert(tostring(e):find("failure1") ~= nil)
+
+        local r, e = ok2()
+        assert(r == "!")
+        assert(e == nil)
+
+        local r, e = err2()
+        assert(r == nil)
+        assert(tostring(e):find("failure2") ~= nil)
+    "#,
+    )
+    .exec()?;
+
+    // Try to convert Result into MultiValue
+    let ok1 = Ok::<(), Error>(());
+    let multi_ok1 = ok1.into_lua_multi(&lua)?;
+    assert_eq!(multi_ok1.len(), 0);
+    let err1 = Err::<(), _>("failure1");
+    let multi_err1 = err1.into_lua_multi(&lua)?;
+    assert_eq!(multi_err1.len(), 2);
+    assert_eq!(multi_err1[0], Value::Nil);
+    assert_eq!(multi_err1[1].as_str().unwrap(), "failure1");
+
+    let ok2 = Ok::<_, Error>("!");
+    let multi_ok2 = ok2.into_lua_multi(&lua)?;
+    assert_eq!(multi_ok2.len(), 1);
+    assert_eq!(multi_ok2[0].as_str().unwrap(), "!");
+    let err2 = Err::<String, _>("failure2".into_lua_err());
+    let multi_err2 = err2.into_lua_multi(&lua)?;
+    assert_eq!(multi_err2.len(), 2);
+    assert_eq!(multi_err2[0], Value::Nil);
+    assert!(matches!(multi_err2[1], Value::Error(_)));
+    assert_eq!(multi_err2[1].to_string()?, "failure2");
+
+    Ok(())
+}

tests/scope.rs

@@ -155,14 +155,14 @@ fn test_scope_userdata_functions() -> Result<()> {
 
     impl<'a> UserData for MyUserData<'a> {
         fn add_methods<'lua, M: UserDataMethods<'lua, Self>>(methods: &mut M) {
-            methods.add_meta_function(MetaMethod::Add, |lua, ()| {
+            methods.add_meta_method(MetaMethod::Add, |lua, this, ()| {
                 let globals = lua.globals();
-                globals.set("i", globals.get::<_, i64>("i")? + 1)?;
+                globals.set("i", globals.get::<_, i64>("i")? + this.0)?;
                 Ok(())
             });
-            methods.add_meta_function(MetaMethod::Sub, |lua, ()| {
+            methods.add_meta_method(MetaMethod::Sub, |lua, this, ()| {
                 let globals = lua.globals();
-                globals.set("i", globals.get::<_, i64>("i")? + 1)?;
+                globals.set("i", globals.get::<_, i64>("i")? + this.0)?;
                 Ok(())
             });
         }
@@ -170,7 +170,7 @@ fn test_scope_userdata_functions() -> Result<()> {
 
     let lua = Lua::new();
 
-    let dummy = 0;
+    let dummy = 1;
     let f = lua
         .load(
             r#"
@@ -178,7 +178,7 @@ fn test_scope_userdata_functions() -> Result<()> {
             return function(u)
                 _ = u + u
                 _ = u - 1
-                _ = 1 + u
+                _ = u + 1
             end
         "#,
         )
@@ -257,7 +257,7 @@ fn test_scope_userdata_mismatch() -> Result<()> {
 fn test_scope_userdata_drop() -> Result<()> {
     let lua = Lua::new();
 
-    struct MyUserData(Rc<()>);
+    struct MyUserData(#[allow(unused)] Rc<()>);
 
     impl UserData for MyUserData {
         fn add_methods<'lua, M: UserDataMethods<'lua, Self>>(methods: &mut M) {
@@ -265,7 +265,7 @@ fn test_scope_userdata_drop() -> Result<()> {
         }
     }
 
-    struct MyUserDataArc(Arc<()>);
+    struct MyUserDataArc(#[allow(unused)] Arc<()>);
 
     impl UserData for MyUserDataArc {}
 
@@ -315,7 +315,7 @@ fn test_scope_userdata_drop() -> Result<()> {
 fn test_scope_nonstatic_userdata_drop() -> Result<()> {
     let lua = Lua::new();
 
-    struct MyUserData<'a>(&'a Cell<i64>, Arc<()>);
+    struct MyUserData<'a>(&'a Cell<i64>, #[allow(unused)] Arc<()>);
 
     impl<'a> UserData for MyUserData<'a> {
         fn add_methods<'lua, M: UserDataMethods<'lua, Self>>(methods: &mut M) {
@@ -326,7 +326,7 @@ fn test_scope_nonstatic_userdata_drop() -> Result<()> {
         }
     }
 
-    struct MyUserDataArc(Arc<()>);
+    struct MyUserDataArc(#[allow(unused)] Arc<()>);
 
     impl UserData for MyUserDataArc {}
 

tests/serde.rs

@@ -99,7 +99,7 @@ fn test_serialize_in_scope() -> LuaResult<()> {
         Err(e) => panic!("expected destructed error, got {}", e),
     }
 
-    struct MyUserDataRef<'a>(&'a ());
+    struct MyUserDataRef<'a>(#[allow(unused)] &'a ());
 
     impl<'a> UserData for MyUserDataRef<'a> {}
 
@@ -115,6 +115,21 @@ fn test_serialize_in_scope() -> LuaResult<()> {
     Ok(())
 }
 
+#[test]
+fn test_serialize_any_userdata() -> Result<(), Box<dyn StdError>> {
+    let lua = Lua::new();
+
+    let json_val = serde_json::json!({
+        "a": 1,
+        "b": "test",
+    });
+    let json_ud = lua.create_ser_any_userdata(json_val)?;
+    let json_str = serde_json::to_string_pretty(&json_ud)?;
+    assert_eq!(json_str, "{\n  \"a\": 1,\n  \"b\": \"test\"\n}");
+
+    Ok(())
+}
+
 #[test]
 fn test_serialize_failure() -> Result<(), Box<dyn StdError>> {
     #[derive(Serialize)]
@@ -697,3 +712,61 @@ fn test_from_value_sorted() -> Result<(), Box<dyn StdError>> {
 
     Ok(())
 }
+
+#[test]
+fn test_arbitrary_precision() {
+    let lua = Lua::new();
+
+    let opts = SerializeOptions::new().detect_serde_json_arbitrary_precision(true);
+
+    // Number
+    let num = serde_json::Value::Number(serde_json::Number::from_f64(1.244e2).unwrap());
+    let num = lua.to_value_with(&num, opts).unwrap();
+    assert_eq!(num, Value::Number(1.244e2));
+
+    // Integer
+    let num = serde_json::Value::Number(serde_json::Number::from_f64(123.0).unwrap());
+    let num = lua.to_value_with(&num, opts).unwrap();
+    assert_eq!(num, Value::Integer(123));
+
+    // Max u64
+    let num = serde_json::Value::Number(serde_json::Number::from(i64::MAX));
+    let num = lua.to_value_with(&num, opts).unwrap();
+    assert_eq!(num, Value::Number(i64::MAX as f64));
+
+    // Check that the option is disabled by default
+    let num = serde_json::Value::Number(serde_json::Number::from_f64(1.244e2).unwrap());
+    let num = lua.to_value(&num).unwrap();
+    assert_eq!(num.type_name(), "table");
+    assert_eq!(
+        format!("{:#?}", num),
+        "{\n  [\"$serde_json::private::Number\"] = \"124.4\",\n}"
+    );
+}
+
+#[cfg(feature = "luau")]
+#[test]
+fn test_buffer_serialize() {
+    let lua = Lua::new();
+
+    let buf = lua.create_buffer(&[1, 2, 3, 4]).unwrap();
+    let val = serde_value::to_value(&buf).unwrap();
+    assert_eq!(val, serde_value::Value::Bytes(vec![1, 2, 3, 4]));
+
+    // Try empty buffer
+    let buf = lua.create_buffer(&[]).unwrap();
+    let val = serde_value::to_value(&buf).unwrap();
+    assert_eq!(val, serde_value::Value::Bytes(vec![]));
+}
+
+#[cfg(feature = "luau")]
+#[test]
+fn test_buffer_from_value() {
+    let lua = Lua::new();
+
+    let buf = lua.create_buffer(&[1, 2, 3, 4]).unwrap();
+    let val = lua
+        .from_value::<serde_value::Value>(Value::UserData(buf))
+        .unwrap();
+    assert_eq!(val, serde_value::Value::Bytes(vec![1, 2, 3, 4]));
+}

tests/string.rs

@@ -99,6 +99,19 @@ fn test_string_debug() -> Result<()> {
     Ok(())
 }
 
+#[test]
+fn test_string_pointer() -> Result<()> {
+    let lua = Lua::new();
+
+    let str1 = lua.create_string("hello")?;
+    let str2 = lua.create_string("hello")?;
+
+    // Lua uses string interning, so these should be the same
+    assert_eq!(str1.to_pointer(), str2.to_pointer());
+
+    Ok(())
+}
+
 #[cfg(all(feature = "unstable", not(feature = "send")))]
 #[test]
 fn test_owned_string() -> Result<()> {

tests/table.rs

@@ -369,6 +369,19 @@ fn test_table_eq() -> Result<()> {
     Ok(())
 }
 
+#[test]
+fn test_table_pointer() -> Result<()> {
+    let lua = Lua::new();
+
+    let table1 = lua.create_table()?;
+    let table2 = lua.create_table()?;
+
+    assert_eq!(table1.to_pointer(), table1.clone().to_pointer());
+    assert_ne!(table1.to_pointer(), table2.to_pointer());
+
+    Ok(())
+}
+
 #[test]
 fn test_table_error() -> Result<()> {
     let lua = Lua::new();

tests/tests.rs

@@ -504,44 +504,6 @@ fn test_panic() -> Result<()> {
     Ok(())
 }
 
-#[test]
-fn test_result_conversions() -> Result<()> {
-    let lua = Lua::new();
-    let globals = lua.globals();
-
-    let ok = lua.create_function(|_, ()| Ok(Ok::<(), Error>(())))?;
-    let err = lua.create_function(|_, ()| Ok(Err::<(), _>("failure1".into_lua_err())))?;
-    let ok2 = lua.create_function(|_, ()| Ok(Ok::<_, Error>("!".to_owned())))?;
-    let err2 = lua.create_function(|_, ()| Ok(Err::<String, _>("failure2".into_lua_err())))?;
-
-    globals.set("ok", ok)?;
-    globals.set("ok2", ok2)?;
-    globals.set("err", err)?;
-    globals.set("err2", err2)?;
-
-    lua.load(
-        r#"
-        local r, e = ok()
-        assert(r == nil and e == nil)
-
-        local r, e = err()
-        assert(r == nil)
-        assert(tostring(e):find("failure1") ~= nil)
-
-        local r, e = ok2()
-        assert(r == "!")
-        assert(e == nil)
-
-        local r, e = err2()
-        assert(r == nil)
-        assert(tostring(e):find("failure2") ~= nil)
-    "#,
-    )
-    .exec()?;
-
-    Ok(())
-}
-
 #[test]
 fn test_num_conversion() -> Result<()> {
     let lua = Lua::new();
@@ -781,7 +743,7 @@ fn test_registry_value() -> Result<()> {
 
 #[test]
 fn test_drop_registry_value() -> Result<()> {
-    struct MyUserdata(Arc<()>);
+    struct MyUserdata(#[allow(unused)] Arc<()>);
 
     impl UserData for MyUserdata {}
 

tests/thread.rs

@@ -101,7 +101,7 @@ fn test_thread_reset() -> Result<()> {
 
     let lua = Lua::new();
 
-    struct MyUserData(Arc<()>);
+    struct MyUserData(#[allow(unused)] Arc<()>);
     impl UserData for MyUserData {}
 
     let arc = Arc::new(());
@@ -191,6 +191,19 @@ fn test_coroutine_panic() {
     }
 }
 
+#[test]
+fn test_thread_pointer() -> Result<()> {
+    let lua = Lua::new();
+
+    let func = lua.load("return 123").into_function()?;
+    let thread = lua.create_thread(func.clone())?;
+
+    assert_eq!(thread.to_pointer(), thread.clone().to_pointer());
+    assert_ne!(thread.to_pointer(), lua.current_thread().to_pointer());
+
+    Ok(())
+}
+
 #[cfg(all(feature = "unstable", not(feature = "send")))]
 #[test]
 fn test_owned_thread() -> Result<()> {

tests/userdata.rs

@@ -370,6 +370,8 @@ fn test_userdata_take() -> Result<()> {
             r => panic!("improper return for destructed userdata: {:?}", r),
         }
 
+        assert!(!userdata.is::<MyUserdata>());
+
         drop(userdata);
         lua.globals().raw_remove("userdata")?;
         lua.gc_collect()?;
@@ -400,7 +402,7 @@ fn test_userdata_take() -> Result<()> {
 
 #[test]
 fn test_userdata_destroy() -> Result<()> {
-    struct MyUserdata(Arc<()>);
+    struct MyUserdata(#[allow(unused)] Arc<()>);
 
     impl UserData for MyUserdata {}
 
@@ -951,6 +953,20 @@ fn test_userdata_method_errors() -> Result<()> {
     Ok(())
 }
 
+#[test]
+fn test_userdata_pointer() -> Result<()> {
+    let lua = Lua::new();
+
+    let ud1 = lua.create_any_userdata("hello")?;
+    let ud2 = lua.create_any_userdata("hello")?;
+
+    assert_eq!(ud1.to_pointer(), ud1.clone().to_pointer());
+    // Different userdata objects with the same value should have different pointers
+    assert_ne!(ud1.to_pointer(), ud2.to_pointer());
+
+    Ok(())
+}
+
 #[cfg(all(feature = "unstable", not(feature = "send")))]
 #[test]
 fn test_owned_userdata() -> Result<()> {