bug#41572: 28.0.50; [PATCH] Support plain project marked with file .emacs-project

[Dmitry Gutov]

On 30/11/2022 22:32, Eli Zaretskii wrote:
> > Date: Wed, 30 Nov 2022 20:52:32 +0200
> > Cc: philipk@posteo.net, rudi@constantly.at, eric@ericabrahamsen.net,
> >   cjpeople2013@gmail.com, theo@thornhill.no, mardani29@yahoo.es,
> >   joaotavora@gmail.com, manuel.uberti@inventati.org, juri@linkov.net,
> >   salutis@me.com, arstoffel@gmail.com, 41572@debbugs.gnu.org
> > From: Dmitry Gutov <dgutov@yandex.ru>
> >
> > > > Eli, what do you think about this feature
> > > > (project-vc-extra-root-markers) for emacs-29?
> > > Where can I see the code that you are proposing?
> >
> > Here you go, I also added some documentation updates and 2 tests.
>
> Thanks.  But I don't see any tests...

Sorry, missed them in this patch. They don't really need an advance 
review, though, so just see them later.

> > +;; If the repository is using any other VCS than Git or Hg, the file
> > +;; listing uses the default mechanism based on 'find'.
>
> Instead of a literal 'find', this should probably say something like
>
>    If the repository is using any other VCS than Git or Hg, the file
>    listing uses the default mechanism based on the program specified by
>    `find-program'.

Sure, thanks.

> >   (defun project-try-vc (dir)
> > +  (defvar vc-svn-admin-directory)
> > +  (require 'vc-svn)
> > +  ;; FIXME: Learn to invalidate when the value of
> > +  ;; `project-vc-merge-submodules' or `project-vc-extra-root-markers'
> > +  ;; changes.
> >     (or (vc-file-getprop dir 'project-vc)
> > -      (let* ((backend (ignore-errors (vc-responsible-backend dir)))
> > +      (let* ((backend-markers-alist `((Git . ".git")
> > +                                      (Hg . ".hg")
> > +                                      (Bzr . ".bzr")
> > +                                      (SVN . ,vc-svn-admin-directory)
> > +                                      (DARCS . "_darcs")
> > +                                      (Fossil . ".fslckout")))
> > +             (backend-markers
> > +              (delete
> > +               nil
> > +               (mapcar
> > +                (lambda (b) (assoc-default b backend-markers-alist))
> > +                vc-handled-backends)))
> > +             (marker-re
> > +              (mapconcat
> > +               (lambda (m) (format "\\(%s\\)" (wildcard-to-regexp m)))
> > +               (append backend-markers project-vc-extra-root-markers)
> > +               "\\|"))
> > +             (locate-dominating-stop-dir-regexp
> > +              (or vc-ignore-dir-regexp locate-dominating-stop-dir-regexp))
> > +             last-matches
> >                (root
> > -              (pcase backend
> > -                ('Git
> > -                 ;; Don't stop at submodule boundary.
> > -                 (or (vc-file-getprop dir 'project-git-root)
> > -                     (let ((root (vc-call-backend backend 'root dir)))
> > -                       (vc-file-setprop
> > -                        dir 'project-git-root
> > -                        (if (and
> > -                             ;; FIXME: Invalidate the cache when the value
> > -                             ;; of this variable changes.
> > -                             project-vc-merge-submodules
> > -                             (project--submodule-p root))
> > -                            (let* ((parent (file-name-directory
> > -                                            (directory-file-name root))))
> > -                              (vc-call-backend backend 'root parent))
> > -                          root)))))
> > -                ('nil nil)
> > -                (_ (ignore-errors (vc-call-backend backend 'root dir)))))
> > +              (locate-dominating-file
> > +               dir
> > +               (lambda (d)
> > +                 (setq last-matches (directory-files d nil marker-re t 100)))))
> > +             (backend
> > +              (cl-find-if
> > +               (lambda (b)
> > +                 (member (assoc-default b backend-markers-alist)
> > +                         last-matches))
> > +               vc-handled-backends))
> >                project)
> > +        (when (and
> > +               (eq backend 'Git)
> > +               project-vc-merge-submodules
> > +               (project--submodule-p root))
> > +          (let* ((parent (file-name-directory (directory-file-name root))))
> > +            (setq root (vc-call-backend 'Git 'root parent))))
> >           (when root
> >             (setq project (list 'vc backend root))
> >             ;; FIXME: Cache for a shorter time.
>
> This is a significant change of the implementation of a public API.  Isn't
> it risky to make such changes on the release branch?
>
> But if you are okay with that, it's fine by me.

A little bit, yeah. But I've done some dogfooding, and we have a couple 
of months before the release, right?