On 21/10/23 15:21, Juri Linkov wrote:
 >> +(defun read-dir-locals-file ()
 >> +  "Read a dir-locals filename using completion.
 >> +Intended to be used in the `interactive' spec of 
`add-dir-local-variable',
 >> +`delete-dir-local-variable' and `copy-file-locals-to-dir-locals'.
 >> +
 >> +Returns the filename, expanded."
 >> +  (expand-file-name
 >> +   (read-file-name "File" nil nil
 >
 > The prompt needs a colon.

Fixed.

 >> +                   (lambda (fname)
 >> +                     (member (file-name-nondirectory fname)
 >> +                             (list dir-locals-file
 >> + (replace-regexp-in-string
 >> +                                    ".el$" "-2.el" dir-locals-file))))
 >> +                   dir-locals-file)))
 >
 > This needs to be run in the project's root directory
 > where the dir-locals file is saved.  Probably it's not easy
 > to find the root without using project.el.  But when one of the
 > files already exists (either .dir-locals.el or .dir-locals-2.el),
 > then better to use the directory of the existing file by default.

In this new patch, I went for using it if already available and we
couldn't find an existing file by other means.