Treat userdata as Ref

Signed-off-by: Maksym Pavlenko <pavlenko.maksym@gmail.com>

Author: mxpv

src/lua.zig

@@ -629,7 +629,7 @@ pub const Lua = struct {
         string: []const u8,
         table: Table,
         function: Function,
-        userdata: *anyopaque,
+        userdata: Ref,
         lightuserdata: *anyopaque,
 
         /// Releases any resources held by this Value.
@@ -647,6 +647,7 @@ pub const Lua = struct {
             switch (self) {
                 .table => |t| t.deinit(),
                 .function => |f| f.deinit(),
+                .userdata => |u| u.deinit(),
                 else => {}, // No cleanup needed for primitive types
             }
         }

src/stack.zig

@@ -123,7 +123,7 @@ pub fn push(lua: Lua, value: anytype) void {
                     .string => |s| lua.state.pushLString(s),
                     .table => |t| push(lua, t),
                     .function => |f| push(lua, f),
-                    .userdata => |u| lua.state.pushLightUserdata(u), // Note: full userdata push would need more complex handling
+                    .userdata => |u| push(lua, u), // Push userdata reference
                     .lightuserdata => |u| lua.state.pushLightUserdata(u),
                 }
                 return;
@@ -568,8 +568,8 @@ pub fn toValue(lua: Lua, comptime T: type, index: i32) ?T {
                         Lua.Value{ .function = func }
                     else
                         null,
-                    .userdata => if (lua.state.toUserdata(index)) |data|
-                        Lua.Value{ .userdata = data }
+                    .userdata => if (lua.state.isUserdata(index))
+                        Lua.Value{ .userdata = Lua.Ref{ .lua = lua, .ref = lua.state.ref(index) } }
                     else
                         null,
                     .lightuserdata => if (lua.state.toLightUserdata(index)) |data|

src/tests.zig

@@ -817,13 +817,21 @@ test "Value enum all cases" {
         try expect(std.meta.activeTag(back.?) == std.meta.activeTag(case.value));
     }
 
-    // Test userdata (both types push as lightuserdata, so they retrieve as lightuserdata)
+    // Test lightuserdata
     try globals.set("light", Lua.Value{ .lightuserdata = ptr });
-    try globals.set("user", Lua.Value{ .userdata = ptr });
     const light_back = try globals.get("light", Lua.Value);
-    const user_back = try globals.get("user", Lua.Value);
     try expect(light_back.? == .lightuserdata);
-    try expect(user_back.? == .lightuserdata); // Both become lightuserdata when retrieved
+
+    // Test userdata (create proper userdata with reference)
+    _ = lua.state.newUserdata(@sizeOf(i32));
+    const userdata_ref = Lua.Ref.init(lua, -1);
+    lua.state.pop(1); // Remove from stack since we have a reference
+    defer userdata_ref.deinit();
+
+    try globals.set("user", Lua.Value{ .userdata = userdata_ref });
+    const user_back = try globals.get("user", Lua.Value);
+    try expect(user_back.? == .userdata);
+    defer user_back.?.deinit();
 
     // Test table
     const table = lua.createTable(.{});