emacs: Find autoloads in "guix.d" subdirectories.

Co-authored-by: Federico Beffa <beffa@fbengineering.ch>.

* emacs/guix-emacs.el (guix-emacs-find-autoloads-in-directory,
  guix-emacs-subdirs): New functions.
  (guix-emacs-find-autoloads): Search for autoloads in "guix.d"
  subdirectories.
  (guix-emacs-load-autoloads): Add subdirectories to 'load-path'.
* emacs/guix-init.el.in: Do not add guix emacs directory to 'load-path'
  because it will be done by 'guix-emacs-load-autoloads'.  Move
  requiring 'guix-emacs' from the top-level to a clause for checking for
  'guix-package-enable-at-startup'.

emacs/guix-emacs.el

@@ -42,19 +42,40 @@ If PROFILE is nil, use `guix-user-profile'."
   (expand-file-name "share/emacs/site-lisp"
                     (or profile guix-user-profile)))
 
+(defun guix-emacs-find-autoloads-in-directory (directory)
+  "Return list of Emacs 'autoloads' files in DIRECTORY."
+  (directory-files directory 'full-name "-autoloads\\.el\\'" 'no-sort))
+
+(defun guix-emacs-subdirs (directory)
+  "Return list of DIRECTORY subdirectories."
+  (cl-remove-if (lambda (file)
+                  (or (string-match-p (rx "/." string-end) file)
+                      (string-match-p (rx "/.." string-end) file)
+                      (not (file-directory-p file))))
+                (directory-files directory 'full-name nil 'no-sort)))
+
 (defun guix-emacs-find-autoloads (&optional profile)
   "Return list of autoloads of Emacs packages installed in PROFILE.
 If PROFILE is nil, use `guix-user-profile'.
 Return nil if there are no emacs packages installed in PROFILE."
-  (let ((dir (guix-emacs-directory profile)))
-    (if (file-directory-p dir)
-        (directory-files dir 'full-name "-autoloads\\.el\\'")
+  (let ((elisp-root-dir (guix-emacs-directory profile)))
+    (if (file-directory-p elisp-root-dir)
+        (let ((elisp-pkgs-dir (expand-file-name "guix.d" elisp-root-dir))
+              (root-autoloads (guix-emacs-find-autoloads-in-directory
+                               elisp-root-dir)))
+          (if (file-directory-p elisp-pkgs-dir)
+              (let ((pkgs-autoloads
+                     (cl-mapcan #'guix-emacs-find-autoloads-in-directory
+                                (guix-emacs-subdirs elisp-pkgs-dir))))
+                (append root-autoloads pkgs-autoloads))
+            root-autoloads))
       (message "Directory '%s' does not exist." dir)
       nil)))
 
 ;;;###autoload
 (defun guix-emacs-load-autoloads (&optional all)
   "Load autoloads for Emacs packages installed in a user profile.
+Add autoloads directories to `load-path'.
 If ALL is nil, activate only those packages that were installed
 after the last activation, otherwise activate all Emacs packages
 installed in `guix-user-profile'."
@@ -65,6 +86,8 @@ installed in `guix-user-profile'."
                   (cl-nset-difference autoloads guix-emacs-autoloads
                                       :test #'string=))))
     (dolist (file files)
+      (cl-pushnew (file-name-directory file) load-path
+                  :test #'string=)
       (load file 'noerror))
     (setq guix-emacs-autoloads autoloads)))
 

emacs/guix-init.el.in

@@ -1,5 +1,4 @@
 (require 'guix-autoloads)
-(require 'guix-emacs)
 
 (defvar guix-load-path
   (replace-regexp-in-string "${prefix}" "@prefix@" "@emacsuidir@")
@@ -13,9 +12,8 @@ avoid loading autoloads of Emacs packages installed in
   :type 'boolean
   :group 'guix)
 
-(add-to-list 'load-path (guix-emacs-directory))
-
 (when guix-package-enable-at-startup
+  (require 'guix-emacs)
   (guix-emacs-load-autoloads 'all))
 
 (provide 'guix-init)