Re: project.el: git submodules?

[Dmitry Gutov]

On 15.05.2020 00:38, Michael Welsh Duggan wrote:
> I think you can just look for ^gitdir:.*/\.git/modules/
> After all, I believe submodules all end up having their metadata within
> .git/modules.

OK.

Here's a patch you can try:

diff --git a/lisp/progmodes/project.el b/lisp/progmodes/project.el
index ac56537b97..bc79e7591b 100644
--- a/lisp/progmodes/project.el
+++ b/lisp/progmodes/project.el
@@ -268,9 +268,24 @@ project-try-vc
           (pcase backend
             ('Git
              ;; Don't stop at submodule boundary.
-             (or (vc-file-getprop dir 'project-git-root)
-                 (vc-file-setprop dir 'project-git-root
-                                  (vc-find-root dir ".git/"))))
+             (or (vc-file-getprop dir 'project-vc-root)
+                 (let* ((default-directory dir)
+                        (root (vc-root-dir)))
+                   (vc-file-setprop
+                    dir 'project-vc-root
+                    (cond
+                     ((file-directory-p ".git")
+                      root)
+                     ((with-temp-buffer
+                        (insert-file-contents ".git")
+                        (goto-char (point-min))
+                        (looking-at "gitdir:[./]+/\.git/modules/"))
+                      (let* ((parent (file-name-directory
+                                      (directory-file-name root)))
+                             (default-directory parent))
+                        (vc-root-dir)))
+                     (t root)))
+                   )))
             ('nil nil)
             (_ (ignore-errors (vc-call-backend backend 'root dir))))))
     (and root (cons 'vc root))))