[hvdijk]

Beware that PATH being unset or empty is a special case and does not necessarily mean that no directories are searched. Different shells handle it differently, and other utilities spawned by the shells handle it themselves in a way that may or may not match the shell. Whether setting PATH to $dir if it was previously unset or empty is the right thing to do is therefore a matter of opinion. Personally, I would stay out of that mess and either issue an error or leave PATH unmodified.