fix

Author: CppCXY

crates/luars/src/lua_value/mod.rs

@@ -166,11 +166,11 @@ impl LuaUpvalue {
                 drop(state);
                 // Find the frame and read the register from global stack
                 if let Some(frame) = frames.iter().find(|f| f.frame_id == frame_id) {
-                    if register < frame.top {
-                        let index = frame.base_ptr + register;
-                        if index < register_stack.len() {
-                            return register_stack[index];
-                        }
+                    // Don't check against frame.top, as it might be 0 for functions called with no args
+                    // Instead, just validate the absolute index is within the stack
+                    let index = frame.base_ptr + register;
+                    if index < register_stack.len() {
+                        return register_stack[index];
                     }
                 }
                 LuaValue::nil()
@@ -193,11 +193,11 @@ impl LuaUpvalue {
                 drop(state);
                 // Find the frame and write the register to global stack
                 if let Some(frame) = frames.iter_mut().find(|f| f.frame_id == frame_id) {
-                    if register < frame.top {
-                        let index = frame.base_ptr + register;
-                        if index < register_stack.len() {
-                            register_stack[index] = value;
-                        }
+                    // Don't check against frame.top, as it might be 0 for functions called with no args
+                    // Instead, just validate the absolute index is within the stack
+                    let index = frame.base_ptr + register;
+                    if index < register_stack.len() {
+                        register_stack[index] = value;
                     }
                 }
             }

crates/luars/src/lua_vm/dispatcher/control_instructions.rs

@@ -963,6 +963,11 @@ pub fn exec_tailcall(vm: &mut LuaVM, instr: u32) -> LuaResult<DispatchAction> {
                 .ok_or_else(|| LuaError::RuntimeError("Invalid function pointer".to_string()))?;
             let max_stack_size = unsafe { (*func_ptr).borrow().chunk.max_stack_size };
 
+            // CRITICAL: Before popping the frame, close all upvalues that point to it
+            // This ensures that any closures created in this frame can still access
+            // the captured values after the frame is destroyed
+            vm.close_upvalues_from(base);
+
             // Pop current frame (tail call optimization)
             let old_base = base; // Already extracted
             // return_count already extracted

crates/luars/src/lua_vm/mod.rs

@@ -1094,11 +1094,20 @@ impl LuaVM {
             .iter()
             .filter(|uv| {
                 // Check if this upvalue points to stack_pos or higher
+                // We need to find the frame that owns this upvalue
                 for frame in self.frames.iter() {
-                    for reg_idx in 0..frame.top {
-                        let absolute_pos = frame.base_ptr + reg_idx;
-                        if absolute_pos >= stack_pos && uv.points_to(frame.frame_id, reg_idx) {
-                            return true;
+                    // Check all possible registers in this frame
+                    // Use max_stack_size instead of top, because top might be 0 for functions
+                    // called with no arguments (but they can still have local variables)
+                    if let Some(func_ptr) = frame.function_value.as_function_ptr() {
+                        let max_regs = unsafe { (*func_ptr).borrow().chunk.max_stack_size };
+                        for reg_idx in 0..max_regs {
+                            if uv.points_to(frame.frame_id, reg_idx) {
+                                let absolute_pos = frame.base_ptr + reg_idx;
+                                if absolute_pos >= stack_pos {
+                                    return true;
+                                }
+                            }
                         }
                     }
                 }