martin rudalics wrote:
> We could check (file-writable-p to-name) here too.

And how would you combine the results? There are filesystems where I can
delete a file even if I can't write it. Most FS I know behave this way.
You really don't want filesystem specific code.

No, I believe file-writable-p should be checked to determine whether you
want to delete and recreate the backup, or write to an existing backup.

Once you are determined that you want to delete the backup, you should
simply try to do so, as I guess that's the only truly portable way of
figuring out whether you are allowed to.