Require environment to be a Table instead of Value in Chunks.

In addition to that, `AsChunk::env()` renamed to `AsChunk::environment()`.

mlua_derive/src/lib.rs

@@ -84,26 +84,26 @@ pub fn chunk(input: TokenStream) -> TokenStream {
     });
 
     let wrapped_code = quote! {{
-        use ::mlua::{AsChunk, ChunkMode, Lua, Result, Value};
+        use ::mlua::{AsChunk, ChunkMode, Lua, Result, Table};
         use ::std::borrow::Cow;
         use ::std::io::Result as IoResult;
         use ::std::sync::Mutex;
 
-        struct InnerChunk<F: for <'a> FnOnce(&'a Lua) -> Result<Value<'a>>>(Mutex<Option<F>>);
+        struct InnerChunk<F: for <'a> FnOnce(&'a Lua) -> Result<Table<'a>>>(Mutex<Option<F>>);
 
         impl<F> AsChunk<'static> for InnerChunk<F>
         where
-            F: for <'a> FnOnce(&'a Lua) -> Result<Value<'a>>,
+            F: for <'a> FnOnce(&'a Lua) -> Result<Table<'a>>,
         {
-            fn env<'lua>(&self, lua: &'lua Lua) -> Result<Value<'lua>> {
+            fn environment<'lua>(&self, lua: &'lua Lua) -> Result<Option<Table<'lua>>> {
                 if #caps_len > 0 {
                     if let Ok(mut make_env) = self.0.lock() {
                         if let Some(make_env) = make_env.take() {
-                            return make_env(lua);
+                            return make_env(lua).map(Some);
                         }
                     }
                 }
-                Ok(Value::Nil)
+                Ok(None)
             }
 
             fn mode(&self) -> Option<ChunkMode> {
@@ -115,9 +115,9 @@ pub fn chunk(input: TokenStream) -> TokenStream {
             }
         }
 
-        fn annotate<F: for<'a> FnOnce(&'a Lua) -> Result<Value<'a>>>(f: F) -> F { f }
+        fn annotate<F: for<'a> FnOnce(&'a Lua) -> Result<Table<'a>>>(f: F) -> F { f }
 
-        let make_env = annotate(move |lua: &Lua| -> Result<Value> {
+        let make_env = annotate(move |lua: &Lua| -> Result<Table> {
             let globals = lua.globals();
             let env = lua.create_table()?;
             let meta = lua.create_table()?;
@@ -128,7 +128,7 @@ pub fn chunk(input: TokenStream) -> TokenStream {
             #(#caps)*
 
             env.set_metatable(Some(meta));
-            Ok(Value::Table(env))
+            Ok(env)
         });
 
         InnerChunk(Mutex::new(Some(make_env)))

src/chunk.rs

@@ -5,10 +5,11 @@ use std::io::Result as IoResult;
 use std::path::{Path, PathBuf};
 use std::string::String as StdString;
 
-use crate::error::{Error, Result};
+use crate::error::{Error, ErrorContext, Result};
 use crate::function::Function;
 use crate::lua::Lua;
-use crate::value::{FromLuaMulti, IntoLua, IntoLuaMulti, Value};
+use crate::table::Table;
+use crate::value::{FromLuaMulti, IntoLua, IntoLuaMulti};
 
 #[cfg(feature = "async")]
 use futures_util::future::{self, LocalBoxFuture};
@@ -26,9 +27,9 @@ pub trait AsChunk<'a> {
     /// Returns optional chunk [environment]
     ///
     /// [environment]: https://www.lua.org/manual/5.4/manual.html#2.2
-    fn env<'lua>(&self, lua: &'lua Lua) -> Result<Value<'lua>> {
+    fn environment<'lua>(&self, lua: &'lua Lua) -> Result<Option<Table<'lua>>> {
         let _lua = lua; // suppress warning
-        Ok(Value::Nil)
+        Ok(None)
     }
 
     /// Returns optional chunk mode (text or binary)
@@ -103,7 +104,7 @@ impl AsChunk<'static> for PathBuf {
 pub struct Chunk<'lua, 'a> {
     pub(crate) lua: &'lua Lua,
     pub(crate) name: StdString,
-    pub(crate) env: Result<Value<'lua>>,
+    pub(crate) env: Result<Option<Table<'lua>>>,
     pub(crate) mode: Option<ChunkMode>,
     pub(crate) source: IoResult<Cow<'a, [u8]>>,
     #[cfg(feature = "luau")]
@@ -254,9 +255,9 @@ impl<'lua, 'a> Chunk<'lua, 'a> {
         self
     }
 
-    /// Sets the first upvalue (`_ENV`) of the loaded chunk to the given value.
+    /// Sets the environment of the loaded chunk to the given value.
     ///
-    /// Lua main chunks always have exactly one upvalue, and this upvalue is used as the `_ENV`
+    /// In Lua >=5.2 main chunks always have exactly one upvalue, and this upvalue is used as the `_ENV`
     /// variable inside the chunk. By default this value is set to the global environment.
     ///
     /// Calling this method changes the `_ENV` upvalue to the value provided, and variables inside
@@ -266,7 +267,10 @@ impl<'lua, 'a> Chunk<'lua, 'a> {
     /// necessary to populate the environment in order for scripts using custom environments to be
     /// useful.
     pub fn set_environment<V: IntoLua<'lua>>(mut self, env: V) -> Self {
-        self.env = env.into_lua(self.lua);
+        self.env = env
+            .into_lua(self.lua)
+            .and_then(|val| self.lua.unpack(val))
+            .context("bad environment value");
         self
     }
 
@@ -414,7 +418,7 @@ impl<'lua, 'a> Chunk<'lua, 'a> {
                     self.mode = Some(ChunkMode::Binary);
                 }
                 #[cfg(not(feature = "luau"))]
-                if let Ok(func) = self.lua.load_chunk(None, Value::Nil, None, source.as_ref()) {
+                if let Ok(func) = self.lua.load_chunk(None, None, None, source.as_ref()) {
                     let data = func.dump(false);
                     self.source = Ok(Cow::Owned(data));
                     self.mode = Some(ChunkMode::Binary);

src/lua.rs

@@ -1319,7 +1319,7 @@ impl Lua {
         Chunk {
             lua: self,
             name: chunk.name().unwrap_or_else(|| caller.to_string()),
-            env: chunk.env(self),
+            env: chunk.environment(self),
             mode: chunk.mode(),
             source: chunk.source(),
             #[cfg(feature = "luau")]
@@ -1330,7 +1330,7 @@ impl Lua {
     pub(crate) fn load_chunk<'lua>(
         &'lua self,
         name: Option<&CStr>,
-        env: Value<'lua>,
+        env: Option<Table>,
         mode: Option<ChunkMode>,
         source: &[u8],
     ) -> Result<Function<'lua>> {
@@ -1353,8 +1353,8 @@ impl Lua {
                 mode_str,
             ) {
                 ffi::LUA_OK => {
-                    if env != Value::Nil {
-                        self.push_value(env)?;
+                    if let Some(env) = env {
+                        self.push_ref(&env.0);
                         #[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52"))]
                         ffi::lua_setupvalue(state, -2, 1);
                         #[cfg(any(feature = "lua51", feature = "luajit", feature = "luau"))]