Re: Why does (file-exists-p "") return t?

[Gregory Heytings]

> I just noticed that (file-exists-p “”) returns t on my system (Emacs 
> 28.2 on Arch Linux).
>
> I am not familiar with Emacs’ file handling internals, so the answer 
> might be obvious.
>
> However, I did not find any mention of this case in the docstring or the 
> Elisp manual.

When the argument to file-exists-p is not an absolute file name, it is 
understood as being relative to default-directory.  Therefore with an 
empty string, file-exists-p checks whether default-directory exists, which 
is normally the case.  But

(let ((default-directory "/nonexistent")) (file-exists-p ""))

returns nil.