[Bug libstdc++/106461] New: filesystem::path("//.").parent_path() results in path("/") and not path("//")

[services+gccbugs at vasama dot org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106461

            Bug ID: 106461
           Summary: filesystem::path("//.").parent_path() results in
                    path("/") and not path("//")
           Product: gcc
           Version: 12.1.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: services+gccbugs at vasama dot org
  Target Milestone: ---

path("//.").parent_path().string() returns "/"s and not "//"s as might be
expected.
path("//").parent_path().string() returns "//"s as expected.

https://godbolt.org/z/sT5zn7zM9

#include <filesystem>
#include <cassert>
int main() {
    assert(std::filesystem::path("//").parent_path().string() == "//");
    assert(std::filesystem::path("//.").parent_path().string() == "//");
}