File#to_path shall be deleted
[Feature #13568] sheds light on situations where a File might not have its corresponding path. I understand that this is a nature of a file in general, that it might or might not have such thing. I don't argue that fact.
Problem is however, that ruby's File class has its to_path method. The to_path method is used internally right before calling open(). The intention is clear that the return value of to_path must be something meaningful as an argument to that function. This is impossible for a O_TEMPFILE -created file descriptor, because such file can never be opened again.
So in general, calling to_path over a File instance is a mistake. Let's not do it.
Updated by Eregon (Benoit Daloze) almost 2 years ago
This could break methods which take a pathname-like object and call #to_path when a File is passed to them (e.g. File.delete(file), etc).
I am not saying it is good practice, but I think it should be evaluated for compatibility.
Maybe it's just easier to return nil for to_path on that case, just like File#path?