assertion when removing poly component

[hfn92]

In version 3.14.0

struct TestConcept : entt::type_list<void()>
{
  template<typename Base>
  struct type : Base
  {
    void test()
    {
      entt::poly_call<0>(*this);
    }
  };

  template<typename Type>
  using impl = entt::value_list<&Type::test>;
};

using TestPoly = entt::poly<TestConcept>;

TEST(entt, poly_remove)
{
  entt::registry reg;
  auto e = reg.create();
  reg.emplace<TestPoly>(e, TestPoly{});
  reg.remove<TestPoly>(e);
}

triggers: entt::basic_any<Len, <anonymous> >& entt::basic_any<Len, <anonymous> >::operator=(entt::basic_any<Len, <anonymous> >&&) [with long unsigned int Len = 16; long unsigned int Align = 8]: Assertion ((this != &other) && ("Self move assignment"))' failed.`

entt/core/any.hpp|262| entt::basic_any<Len, <anonymous> >& entt::basic_any<Len, <anonymous> >::operator=(entt::basic_any<Len, <anonymous> >&&) [with long unsigned int Len = 16; long unsigned int Align = 8]: Assertion `((this != &other) && ("Self move assignment"))' failed.
|| Stack trace (most recent call last):
/usr/src/debug/glibc/glibc/nptl/pthread_kill.c|44| __pthread_kill_implementation [0x7f119e0a53f4]
../sysdeps/posix/raise.c|26| raise [0x7f119e04c11f]
/usr/src/debug/glibc/glibc/stdlib/abort.c|79| abort [0x7f119e0334c2]
/usr/src/debug/glibc/glibc/assert/assert.c|94| __assert_fail_base [0x7f119e0333de]
/usr/src/debug/glibc/glibc/assert/assert.c|103| __assert_fail [0x7f119e044176]
/entt/core/any.hpp|262| operator= [0x63c98bb6bc23]
||         259:    * @return This any object.
||         260:    */
||         261:   basic_any &operator=(basic_any &&other) noexcept {
||       > 262:     ENTT_ASSERT(this != &other, "Self move assignment");
||         263: 
||         264:     reset();
/entt/poly/poly.hpp|193| operator= [0x63c98bb8bed5]
||         190:  * @tparam Align Optional alignment requirement.
||         191:  */
||         192: template<typename Concept, std::size_t Len, std::size_t Align>
||       > 193: class basic_poly: private Concept::template type<poly_base<basic_poly<Concept, Len, Align>>> {
||         194:     friend struct poly_base<basic_poly>;
||         195: 
||         196: public:
/usr/include/c++/14.2.1/bits/move.h|178| __exchange<entt::basic_poly<Behaviours::BehaviourConcept, 16, 8>, entt::basic_poly<Behaviours::BehaviourConcept, 16, 8> > [0x63c98be4b241]
||         175:     __exchange(_Tp& __obj, _Up&& __new_val)
||         176:     {
||         177:       _Tp __old_val = std::move(__obj);
||       > 178:       __obj = std::forward<_Up>(__new_val);
||         179:       return __old_val;
||         180:     }
/usr/include/c++/14.2.1/utility|110| exchange<entt::basic_poly<Behaviours::BehaviourConcept, 16, 8>, entt::basic_poly<Behaviours::BehaviourConcept, 16, 8> > [0x63c98be44f7b]
||         107:     exchange(_Tp& __obj, _Up&& __new_val)
||         108:     noexcept(__and_<is_nothrow_move_constructible<_Tp>,
||         109:                is_nothrow_assignable<_Tp&, _Up>>::value)
||       > 110:     { return std::__exchange(__obj, std::forward<_Up>(__new_val)); }
||         111: #endif
||         112: 
||         113: #ifdef  __cpp_lib_as_const // C++ >= 17
/entt/entity/storage.hpp|345| pop [0x63c98be45086]
||         342:             } else {
||         343:                 auto &other = element_at(base_type::size() - 1u);
||         344:                 // destroying on exit allows reentrant destructors
||       > 345:                 [[maybe_unused]] auto unused = std::exchange(elem, std::move(other));
||         346:                 alloc_traits::destroy(allocator, std::addressof(other));
||         347:                 base_type::swap_and_pop(first);
||         348:             }
/entt/entity/mixin.hpp|95| pop [0x63c98be44c10]
||          92:                 const auto entt = *first;
||          93:                 destruction.publish(reg, entt);
||          94:                 const auto it = underlying_type::find(entt);
||       >  95:                 underlying_type::pop(it, it + 1u);
||          96:             }
||          97:         }
||          98:     }
/entt/entity/sparse_set.hpp|816| erase [0x63c98bd52f06]
||         813:      */
||         814:     void erase(const entity_type entt) {
||         815:         const auto it = to_iterator(entt);
||       > 816:         pop(it, it + 1u);
||         817:     }
||         818: 
||         819:     /**
/entt/entity/sparse_set.hpp|845| remove [0x63c98bd52e86]
||         842:      * @return True if the entity is actually removed, false otherwise.
||         843:      */
||         844:     bool remove(const entity_type entt) {
||       > 845:         return contains(entt) && (erase(entt), true);
||         846:     }
||         847: 
||         848:     /**
/entt/entity/registry.hpp|716| remove<entt::basic_poly<Behaviours::BehaviourConcept, 16, 8> > [0x63c98be243ff]
||         713:      */
||         714:     template<typename Type, typename... Other>
||         715:     size_type remove(const entity_type entt) {
||       > 716:         return (assure<Type>().remove(entt) + ... + assure<Other>().remove(entt));
||         717:     }
||         718: 
||         719:     /**
/entt/entity/handle.hpp|257| remove<entt::basic_poly<Behaviours::BehaviourConcept, 16, 8> > [0x63c98be1fcdf]
||         254:     // NOLINTNEXTLINE(modernize-use-nodiscard)
||         255:     size_type remove() const {
||         256:         static_assert(sizeof...(Scope) == 0 || (type_list_contains_v<type_list<Scope...>, Type> && ...), "Invalid type");
||       > 257:         return owner_or_assert().template remove<Type...>(entt);
||         258:     }
||         259: 
||         260:     /**

[skypjack]

Oh, interesting one. I think it's a matter of a missing constructor. Thanks for pointing this out. 🙏

[skypjack]

I decided to remove the assert in any (and meta_any) and stick with the same behavior of the standard library.
That is, when you self move, the object is put in a safe but unspecified state. This should be enough to get your example working again.

[hfn92]

Thanks!