v0.11.1

Before this change, destructor was executed shortly after pushing metatable to ref_thread.

CHANGELOG.md

@@ -1,3 +1,8 @@
+## v0.11.1 (Jul 15, 2025)
+
+- Fixed bug exhausting Lua auxiliary stack and leaving it without reserve (#615)
+- `Lua::push_c_function` now correctly handles OOM for Lua 5.1 and Luau
+
 ## v0.11.0 (Jul 14, 2025)
 
 Changes since v0.11.0-beta.3

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "mlua"
-version = "0.11.0" # remember to update mlua_derive
+version = "0.11.1" # remember to update mlua_derive
 authors = ["Aleksandr Orlenko <zxteam@pm.me>", "kyren <catherine@kyju.org>"]
 rust-version = "1.79.0"
 edition = "2021"

src/state.rs

@@ -1286,8 +1286,24 @@ impl Lua {
     /// This function is unsafe because provides a way to execute unsafe C function.
     pub unsafe fn create_c_function(&self, func: ffi::lua_CFunction) -> Result<Function> {
         let lua = self.lock();
-        ffi::lua_pushcfunction(lua.ref_thread(), func);
-        Ok(Function(lua.pop_ref_thread()))
+        if cfg!(any(feature = "lua54", feature = "lua53", feature = "lua52")) {
+            ffi::lua_pushcfunction(lua.ref_thread(), func);
+            return Ok(Function(lua.pop_ref_thread()));
+        }
+
+        // Lua <5.2 requires memory allocation to push a C function
+        let state = lua.state();
+        {
+            let _sg = StackGuard::new(state);
+            check_stack(state, 3)?;
+
+            if lua.unlikely_memory_error() {
+                ffi::lua_pushcfunction(state, func);
+            } else {
+                protect_lua!(state, 0, 1, |state| ffi::lua_pushcfunction(state, func))?;
+            }
+            Ok(Function(lua.pop_ref()))
+        }
     }
 
     /// Wraps a Rust async function or closure, creating a callable Lua function handle to it.

src/state/extra.rs

@@ -270,7 +270,7 @@ impl ExtraData {
         // Try to grow max stack size
         if self.ref_stack_top >= self.ref_stack_size {
             let mut inc = self.ref_stack_size; // Try to double stack size
-            while inc > 0 && ffi::lua_checkstack(self.ref_thread, inc) == 0 {
+            while inc > 0 && ffi::lua_checkstack(self.ref_thread, inc + REF_STACK_RESERVE) == 0 {
                 inc /= 2;
             }
             if inc == 0 {

src/table.rs

@@ -510,7 +510,7 @@ impl Table {
         let lua = self.0.lua.lock();
         let ref_thread = lua.ref_thread();
         unsafe {
-            if let Some(metatable) = metatable {
+            if let Some(metatable) = &metatable {
                 ffi::lua_pushvalue(ref_thread, metatable.0.index);
             } else {
                 ffi::lua_pushnil(ref_thread);