lexically_relative and lexically_poximate give unexpected result

[madebr]

/home/user/documents/file.txt relative to /home/user/. should be documents/file.txt.

c++17 gives the expected result.

#include <filesystem>
#include <iostream>

namespace fs = std::filesystem;

#include <boost/filesystem.hpp>

namespace bfs = boost::filesystem;

int main() {
    std::string hs = "/home/user/.";
    std::string ps = "/home/user/documents/file.txt";

    {
        fs::path h = hs;
        fs::path p = ps;
        std::cout << "relative: " << p.lexically_relative(h) << '\n'
                  << "proximate: " << p.lexically_proximate(h) << '\n';
    }

    {
        bfs::path h = hs;
        bfs::path p = ps;
        std::cout << "relative: " << p.lexically_relative(h) << '\n'
                  << "proximate: " << p.lexically_relative(h) << '\n';
    }

    return 0;
}

outputs

relative: "documents/file.txt"
proximate: "documents/file.txt"
relative: "../documents/file.txt"
proximate: "../documents/file.txt"

[RichardCrewe]

I've been using c++14 and have encountered this problem on OSX, but not Linux.

Boost 1.67
Compiler on OSX: Apple LLVM version 10.0.0 (clang-1000.10.44.4)
Compiler on Linux: g++ (Ubuntu 5.4.0-6ubuntu1~16.04.11) 5.4.0 20160609

[RichardCrewe]

The trailing dot in the parent path (hs in the example above) is confusing lexically_relative. In my case I discovered it as the boost::filesystem::temp_directory_path() returns a path with a trailing slash on OSX, but not Linux. This trailing slash is effectively normalised to a trailing slash dot by the path iterator.

[rcdailey]

I'm seeing this issue in Boost 1.70. Here is my code example:

namespace fs = boost::filesystem;

int main()
{
    fs::path parentPath("/home/user1/");
    fs::path childPath("/home/user1/Downloads/Books");
    std::cout << childPath.lexically_relative(parentPath) << '\n';
}

Live sample is here

The output is "../Downloads/Books" but should actually be "Downloads/Books". When will this get fixed?

EDIT: Looks like boost::filesystem::relative() also has this issue:

std::cout << fs::relative(childPath, parentPath) << '\n';

Outputs: "../Downloads/Books".

[rcdailey]

@Lastique Thank you for the fix!!