Adding an `or condition without changing code

[Tim Johnson <tim@akwebsoft.com>]

Using emacs 26.1 on ubuntu

I'm implementing dired-single-buffer

The function of the same name has the following `let initialization

(let ((name (or default-dirname (dired-get-filename nil t)))) ;; 
default-dirname is an optional argument to dired-single-buffer

The two conditions to `or are not sufficient if I call 
dired-single-buffer from an unvisited buffer. The result is that `name 
is nil and a string-p, nil error is thrown.

A simple hack is to add a third condition to `or

(let ((name (or default-dirname (dired-get-filename nil t) "~/")))  ;; 
fall-back to /home/user

But, it IS a hack and means I have altered some good citizen's code.

How can that be resolved? Might the solution be a customization of dired?

 From the documentation of dired-get-filename I don't grok a solution....

thanks

-- 

Tim
tj49.com