to_view() tries to dereference out of range iterator

[Sleafar]

Code to reproduce:

#include <iostream>
#include <ctre.hpp>

int main() {
    std::string data = "a\n\nb\n";
    auto lines = ctre::split<"\n">(data);
    for (auto line: lines) {
        //auto t = line.to_string(); //this works
        auto t = line.to_view(); //this doesn't
        std::cout << ">" << t << "<" << std::endl;
    }
}

If this is run in debug mode with MSVC 19.37.32824, it triggers a check in _String_const_iterator.operator*() which detects out of range access. This problem seems only to occur for empty matches at the end of the data.

[Sleafar]

The problem is in line 80 in return_type.hpp:

return &*_begin;

[Alcaro]

Creating a reference to past-the-end counts as accessing it, even if the only thing done is turning it back into a pointer.

It's completely harmless in practice, but yes, compilers tend to be whiny. C++11 added .data() to std::vector for exactly that reason. (Though I suspect that function isn't the solution here.)

[hanickadot]

@Sleafar can you try it now? (I don't have MSVC available)

[Sleafar]

@hanickadot I don't get the error anymore with the current main branch.

[hanickadot]

Thanks for reporting and the check!