(feat): add org-roam-enable-headline-linking (#1030)

When disabled, Org-roam will not attempt to cache headlines, and will not create IDs.

Co-authored-by: Jethro Kuan <jethrokuan95@gmail.com>

org-roam-db.el

@@ -39,6 +39,7 @@
 (require 'org-roam-macs)
 
 (defvar org-roam-directory)
+(defvar org-roam-enable-headline-linking)
 (defvar org-roam-verbose)
 (defvar org-roam-file-name)
 
@@ -472,7 +473,8 @@ connections, nil is returned."
            (org-roam-db--update-tags)
            (org-roam-db--update-titles)
            (org-roam-db--update-refs)
-           (org-roam-db--update-headlines)
+           (when org-roam-enable-headline-linking
+             (org-roam-db--update-headlines))
            (org-roam-db--update-links)))
         (org-roam-buffer--update-maybe :redisplay t)))))
 
@@ -511,9 +513,10 @@ If FORCE, force a rebuild of the cache from scratch."
                       :values $v1]
                      (vector file contents-hash (list :atime atime :mtime mtime)))
                     (setq file-count (1+ file-count))
-                    (when-let ((headlines (org-roam--extract-headlines file)))
-                      (when (org-roam-db--insert-headlines headlines)
-                        (setq headline-count (1+ headline-count)))))
+                    (when org-roam-enable-headline-linking
+                      (when-let ((headlines (org-roam--extract-headlines file)))
+                        (when (org-roam-db--insert-headlines headlines)
+                          (setq headline-count (1+ headline-count))))))
                 (file-error
                  (setq org-roam-files (remove file org-roam-files))
                  (org-roam-db--clear-file file)

org-roam.el

@@ -244,6 +244,11 @@ space-delimited strings.
            (symbol)))
   :group 'org-roam)
 
+(defcustom org-roam-enable-headline-linking t
+  "Enable linking to headlines, which includes automatic :ID: creation and scanning of :ID:s for org-roam database."
+  :type 'boolean
+  :group 'org-roam)
+
 (defcustom org-roam-verbose t
   "Echo messages that are not errors."
   :type 'boolean
@@ -1589,7 +1594,8 @@ M-x info for more information at Org-roam > Installation > Post-Installation Tas
     (advice-add 'rename-file :after #'org-roam--rename-file-advice)
     (advice-add 'delete-file :before #'org-roam--delete-file-advice)
     (when (fboundp 'org-link-set-parameters)
-      (org-link-set-parameters "file" :face 'org-roam--file-link-face :store #'org-roam-store-link)
+      (when org-roam-enable-headline-linking
+        (org-link-set-parameters "file" :face 'org-roam--file-link-face :store #'org-roam-store-link))
       (org-link-set-parameters "id" :face 'org-roam--id-link-face))
     (org-roam-db-build-cache))
    (t