fix issues in LuaJIT builtin library

common/luajit.cc

@@ -188,7 +188,7 @@ void PushVector(lua_State* L, const nf7::Value::ConstVector& v) noexcept {
           if (lua_istable(L, -1)) {  // array
             lua_rawgeti(L, -1, 1);
             const std::string_view type = luaL_checkstring(L, -1);
-            lua_rawgeti(L, -1, 2);
+            lua_rawgeti(L, -2, 2);
             const size_t n = static_cast<size_t>(luaL_checkinteger(L, -1));
             lua_pop(L, 2);
 
@@ -553,6 +553,7 @@ static size_t PushArrayFromBytes(lua_State* L, size_t n, const uint8_t* ptr, con
       [] <bool F = false>() { static_assert(F, "T is invalid"); }();
     }
     lua_rawseti(L, -2, static_cast<int>(i + 1));
+    ptr += sizeof(T);
   }
   return size;
 }

common/luajit_thread.cc

@@ -204,7 +204,11 @@ static void PushMeta(lua_State* L) noexcept {
         const int n = lua_gettop(L);
         std::stringstream st;
         for (int i = 2; i <= n; ++i) {
-          st << lua_tostring(L, i);
+          if (auto msg = lua_tostring(L, i)) {
+            st << msg;
+          } else {
+            return luaL_error(L, "cannot stringify %s", luaL_typename(L, i));
+          }
         }
         logger->Write({lv, st.str()});
         return 0;