Fix Function::deep_clone() method (Luau).

The `lua_clonefunction` function can fail (and trigger GC) so we need to return Result instead of allowing longjmp

Author: khvzak

src/function.rs

@@ -492,16 +492,24 @@ impl Function {
     /// This function returns shallow clone (same handle) for Rust/C functions.
     #[cfg(any(feature = "luau", doc))]
     #[cfg_attr(docsrs, doc(cfg(feature = "luau")))]
-    pub fn deep_clone(&self) -> Self {
+    pub fn deep_clone(&self) -> Result<Self> {
         let lua = self.0.lua.lock();
-        let ref_thread = lua.ref_thread();
+        let state = lua.state();
         unsafe {
-            if ffi::lua_iscfunction(ref_thread, self.0.index) != 0 {
-                return self.clone();
+            let _sg = StackGuard::new(state);
+            check_stack(state, 2)?;
+
+            lua.push_ref(&self.0);
+            if ffi::lua_iscfunction(state, -1) != 0 {
+                return Ok(self.clone());
             }
 
-            ffi::lua_clonefunction(ref_thread, self.0.index);
-            Function(lua.pop_ref_thread())
+            if lua.unlikely_memory_error() {
+                ffi::lua_clonefunction(state, -1);
+            } else {
+                protect_lua!(state, 1, 1, fn(state) ffi::lua_clonefunction(state, -1))?;
+            }
+            Ok(Function(lua.pop_ref()))
         }
     }
 }

tests/function.rs

@@ -306,15 +306,15 @@ fn test_function_deep_clone() -> Result<()> {
 
     lua.globals().set("a", 1)?;
     let func1 = lua.load("a += 1; return a").into_function()?;
-    let func2 = func1.deep_clone();
+    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();
+    let rust_func2 = rust_func.deep_clone()?;
     assert_eq!(rust_func.to_pointer(), rust_func2.to_pointer());
 
     Ok(())