Added flag test to DR_TRAVERSE_CB_RO/RW macros

Author: DoeringChristian

include/drjit/traversable_base.h

@@ -153,6 +153,13 @@ struct DRJIT_EXTRA_EXPORT TraversableBase : public nanobind::intrusive_base {
         static_assert(                                                         \
             std::is_base_of<drjit::TraversableBase,                            \
                             std::remove_pointer_t<decltype(this)>>::value);    \
+        /*                                                                     \
+         * Only traverse the objects for frozen functions, since                 \
+         * accidentally traversing the scene in loops or vcalls can cause      \
+         * issues.                                                             \
+         */                                                                    \
+        if (!jit_flag(JitFlag::EnableObjectTraversal))                         \
+            return;                                                            \
         if constexpr (!std::is_same_v<Base, drjit::TraversableBase>)           \
             Base::traverse_1_cb_ro(payload, fn);                               \
         DRJIT_MAP(DR_TRAVERSE_MEMBER_RO, __VA_ARGS__)                          \
@@ -169,6 +176,16 @@ struct DRJIT_EXTRA_EXPORT TraversableBase : public nanobind::intrusive_base {
 #define DR_TRAVERSE_CB_RW(Base, ...)                                           \
     void traverse_1_cb_rw(void *payload,                                       \
                           drjit::detail::traverse_callback_rw fn) override {   \
+        static_assert(                                                         \
+            std::is_base_of<drjit::TraversableBase,                            \
+                            std::remove_pointer_t<decltype(this)>>::value);    \
+        /*                                                                     \
+         * Only traverse the objects for frozen functions, since               \
+         * accidentally traversing the scene in loops or vcalls can cause      \
+         * issues.                                                             \
+         */                                                                    \
+        if (!jit_flag(JitFlag::EnableObjectTraversal))                         \
+            return;                                                            \
         if constexpr (!std::is_same_v<Base, drjit::TraversableBase>)           \
             Base::traverse_1_cb_rw(payload, fn);                               \
         DRJIT_MAP(DR_TRAVERSE_MEMBER_RW, __VA_ARGS__)                          \