LIBCPP assertion for invalid array element access

[yurivict]

Describe the bug

 799│   _LIBCPP_HIDE_FROM_ABI constexpr const value_type& operator*() const& noexcept {
 800├───> _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(this->has_value(), "optional operator* called on a disengaged value");
 801│     return this->__get();
 802│   }

Call stack:

#0  std::__1::optional<double>::operator*[abi:se190107]() const & (this=0x80460b038) at /usr/include/c++/v1/optional:800
#1  0x00000008019830bf in arb::make_ion_config (build_data=std::unordered_map with 1 element = {...}, ion_data=std::unordered_map with 3 elements = {...}, initial_iconc_map=std::unordered_map with 1 element = {...},
    initial_econc_map=std::unordered_map with 0 elements, initial_rvpot_map=std::unordered_map with 0 elements, data=..., result=std::unordered_map with 0 elements) at /usr/ports/science/arbor/work/arbor-0.11.0/arbor/fvm_layout.cpp:1303
#2  0x000000080197f967 in arb::fvm_build_mechanism_data (gprop=..., cell=..., gj_conns=std::vector of length 0, D=..., cell_idx=0) at /usr/ports/science/arbor/work/arbor-0.11.0/arbor/fvm_layout.cpp:1079
#3  0x00000008019ce3af in arb::fvm_build_mechanism_data(arb::cable_cell_global_properties const&, std::__1::vector<arb::cable_cell, std::__1::allocator<arb::cable_cell> > const&, std::__1::vector<unsigned int, std::__1::allocator<unsigned
 int> > const&, std::__1::unordered_map<unsigned int, std::__1::vector<arb::fvm_gap_junction, std::__1::allocator<arb::fvm_gap_junction> >, std::__1::hash<unsigned int>, std::__1::equal_to<unsigned int>, std::__1::allocator<std::__1::pair
<unsigned int const, std::__1::vector<arb::fvm_gap_junction, std::__1::allocator<arb::fvm_gap_junction> > > > > const&, arb::fvm_cv_discretization const&, arb::execution_context const&)::$_0::operator()(int) const (this=0x8028238f8, i=0)
    at /usr/ports/science/arbor/work/arbor-0.11.0/arbor/fvm_layout.cpp:953
#4  0x00000008019ce304 in arb::threading::parallel_for::apply<arb::fvm_build_mechanism_data(arb::cable_cell_global_properties const&, std::__1::vector<arb::cable_cell, std::__1::allocator<arb::cable_cell> > const&, std::__1::vector<unsign
ed int, std::__1::allocator<unsigned int> > const&, std::__1::unordered_map<unsigned int, std::__1::vector<arb::fvm_gap_junction, std::__1::allocator<arb::fvm_gap_junction> >, std::__1::hash<unsigned int>, std::__1::equal_to<unsigned int>
, std::__1::allocator<std::__1::pair<unsigned int const, std::__1::vector<arb::fvm_gap_junction, std::__1::allocator<arb::fvm_gap_junction> > > > > const&, arb::fvm_cv_discretization const&, arb::execution_context const&)::$_0>(int, int,
int, arb::threading::task_system*, arb::fvm_build_mechanism_data(arb::cable_cell_global_properties const&, std::__1::vector<arb::cable_cell, std::__1::allocator<arb::cable_cell> > const&, std::__1::vector<unsigned int, std::__1::allocator
<unsigned int> > const&, std::__1::unordered_map<unsigned int, std::__1::vector<arb::fvm_gap_junction, std::__1::allocator<arb::fvm_gap_junction> >, std::__1::hash<unsigned int>, std::__1::equal_to<unsigned int>, std::__1::allocator<std::
__1::pair<unsigned int const, std::__1::vector<arb::fvm_gap_junction, std::__1::allocator<arb::fvm_gap_junction> > > > > const&, arb::fvm_cv_discretization const&, arb::execution_context const&)::$_0)::{lambda()#1}::operator()() const (
    this=0x8028238e8) at /usr/ports/science/arbor/work/arbor-0.11.0/arbor/threading/threading.hpp:399
#5  0x00000008019ce218 in arb::threading::task_group::wrap<arb::threading::parallel_for::apply<arb::fvm_build_mechanism_data(arb::cable_cell_global_properties const&, std::__1::vector<arb::cable_cell, std::__1::allocator<arb::cable_cell>
> const&, std::__1::vector<unsigned int, std::__1::allocator<unsigned int> > const&, std::__1::unordered_map<unsigned int, std::__1::vector<arb::fvm_gap_junction, std::__1::allocator<arb::fvm_gap_junction> >, std::__1::hash<unsigned int>,
 std::__1::equal_to<unsigned int>, std::__1::allocator<std::__1::pair<unsigned int const, std::__1::vector<arb::fvm_gap_junction, std::__1::allocator<arb::fvm_gap_junction> > > > > const&, arb::fvm_cv_discretization const&, arb::execution
_context const&)::$_0>(int, int, int, arb::threading::task_system*, arb::fvm_build_mechanism_data(arb::cable_cell_global_properties const&, std::__1::vector<arb::cable_cell, std::__1::allocator<arb::cable_cell> > const&, std::__1::vector<
unsigned int, std::__1::allocator<unsigned int> > const&, std::__1::unordered_map<unsigned int, std::__1::vector<arb::fvm_gap_junction, std::__1::allocator<arb::fvm_gap_junction> >, std::__1::hash<unsigned int>, std::__1::equal_to<unsigne
d int>, std::__1::allocator<std::__1::pair<unsigned int const, std::__1::vector<arb::fvm_gap_junction, std::__1::allocator<arb::fvm_gap_junction> > > > > const&, arb::fvm_cv_discretization const&, arb::execution_context const&)::$_0)::{la
mbda()#1}>::operator()() (this=0x8028238e8) at /usr/ports/science/arbor/work/arbor-0.11.0/arbor/threading/threading.hpp:322

Adding -D_LIBCPP_HARDENING_MODE=_LIBCPP_HARDENING_MODE_NONE fixes runtime asserts by disabling them.

Tests now pass fine.

Context
Version: 0.11.0
clang-19
FreeBSD 15 STABLE

[thorstenhater]

Hi @yurivict,

thanks for reporting. I am confused by this error, there's no optional in that code path.

        const auto& rvpot_on_cable = util::value_by_key_or(initial_rvpot_map, ion, {});

where mcable_map is a linear container so this implementation is relevant:

    // use linear search
    template <
        typename Seq,
        typename Key,
        typename Eq = std::equal_to<>,
        typename Ret = std::remove_reference_t<decltype(get<1>(*begin(std::declval<Seq&&>())))>
    >
    Ret value_by_key_or(std::false_type, Seq&& seq, const Key& key, Ret def, Eq eq=Eq{}) {
        for (auto&& entry: seq) {
            if (eq(get<0>(entry), key)) {
                return get<1>(entry);
            }
        }
        return def;
    }

and the value type is not an optional type either. I am also not seeing this locally or in CI,
so I'd suggest this is a false positive and flagging this in your build script is correct way.