Try another pointer alignment workaround

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

Author: mxpv

src/Lua.zig

@@ -295,8 +295,7 @@ pub fn setCallbacks(self: Self, callbacks: anytype) void {
 
     // Store instance pointer in userdata if it's a pointer
     if (is_instance) {
-        // Ensure the pointer is properly aligned before storing
-        cb.userdata = @ptrCast(@alignCast(callbacks));
+        cb.userdata = @ptrCast(@constCast(callbacks));
     } else {
         cb.userdata = null;
     }
@@ -308,7 +307,9 @@ pub fn setCallbacks(self: Self, callbacks: anytype) void {
 
                 if (comptime is_instance) {
                     const callbacks_struct = state.callbacks();
-                    const instance: *CallbackType = @ptrCast(@alignCast(callbacks_struct.userdata.?));
+                    // C pointers may not have the alignment Zig expects (Zig 0.15)
+                    // See: https://github.com/ziglang/zig/issues/24326
+                    const instance: *CallbackType = @ptrFromInt(@intFromPtr(callbacks_struct.userdata.?));
                     instance.interrupt(&state, @intCast(gc_flag));
                 } else {
                     CallbackType.interrupt(&state, @intCast(gc_flag));
@@ -324,7 +325,7 @@ pub fn setCallbacks(self: Self, callbacks: anytype) void {
 
                 if (comptime is_instance) {
                     const callbacks_struct = state.callbacks();
-                    const instance: *CallbackType = @ptrCast(@alignCast(callbacks_struct.userdata.?));
+                    const instance: *CallbackType = @ptrFromInt(@intFromPtr(callbacks_struct.userdata.?));
                     instance.panic(&state, @intCast(errcode));
                 } else {
                     CallbackType.panic(&state, @intCast(errcode));
@@ -341,7 +342,7 @@ pub fn setCallbacks(self: Self, callbacks: anytype) void {
 
                 if (comptime is_instance) {
                     const callbacks_struct = thread_state.callbacks();
-                    const instance: *CallbackType = @ptrCast(@alignCast(callbacks_struct.userdata.?));
+                    const instance: *CallbackType = @ptrFromInt(@intFromPtr(callbacks_struct.userdata.?));
                     instance.userthread(if (parent_state) |*ps| ps else null, &thread_state);
                 } else {
                     CallbackType.userthread(if (parent_state) |*ps| ps else null, &thread_state);
@@ -375,7 +376,7 @@ pub fn setCallbacks(self: Self, callbacks: anytype) void {
 
                 if (comptime is_instance) {
                     const callbacks_struct = lua.state.callbacks();
-                    const instance: *CallbackType = @ptrCast(@alignCast(callbacks_struct.userdata.?));
+                    const instance: *CallbackType = @ptrFromInt(@intFromPtr(callbacks_struct.userdata.?));
                     instance.debugbreak(&debug_instance, debug_info);
                 } else {
                     CallbackType.debugbreak(&debug_instance, debug_info);
@@ -393,7 +394,7 @@ pub fn setCallbacks(self: Self, callbacks: anytype) void {
 
                 if (comptime is_instance) {
                     const callbacks_struct = lua.state.callbacks();
-                    const instance: *CallbackType = @ptrCast(@alignCast(callbacks_struct.userdata.?));
+                    const instance: *CallbackType = @ptrFromInt(@intFromPtr(callbacks_struct.userdata.?));
                     instance.debugstep(&debug_instance, debug_info);
                 } else {
                     CallbackType.debugstep(&debug_instance, debug_info);
@@ -411,7 +412,7 @@ pub fn setCallbacks(self: Self, callbacks: anytype) void {
 
                 if (comptime is_instance) {
                     const callbacks_struct = lua.state.callbacks();
-                    const instance: *CallbackType = @ptrCast(@alignCast(callbacks_struct.userdata.?));
+                    const instance: *CallbackType = @ptrFromInt(@intFromPtr(callbacks_struct.userdata.?));
                     instance.debuginterrupt(&debug_instance, debug_info);
                 } else {
                     CallbackType.debuginterrupt(&debug_instance, debug_info);
@@ -428,7 +429,7 @@ pub fn setCallbacks(self: Self, callbacks: anytype) void {
 
                 if (comptime is_instance) {
                     const callbacks_struct = lua.state.callbacks();
-                    const instance: *CallbackType = @ptrCast(@alignCast(callbacks_struct.userdata.?));
+                    const instance: *CallbackType = @ptrFromInt(@intFromPtr(callbacks_struct.userdata.?));
                     instance.debugprotectederror(&debug_instance);
                 } else {
                     CallbackType.debugprotectederror(&debug_instance);
@@ -445,7 +446,7 @@ pub fn setCallbacks(self: Self, callbacks: anytype) void {
 
                     if (comptime is_instance) {
                         const callbacks_struct = state.callbacks();
-                        const instance: *CallbackType = @ptrCast(@alignCast(callbacks_struct.userdata.?));
+                        const instance: *CallbackType = @ptrFromInt(@intFromPtr(callbacks_struct.userdata.?));
                         instance.onallocate(&state, osize, nsize);
                     } else {
                         CallbackType.onallocate(&state, osize, nsize);