Merge branch 'db/org-backlink-searcher' into master

init.el

@@ -185,7 +185,7 @@
   (bind-key "<f8>" #'bm-toggle)
   (bind-key "<C-f8>" #'bm-next)
   (bind-key "<C-S-f8>" #'bm-previous)
-  (bind-key "<f9>" #'helm-org-agenda-files-headings)
+  (bind-key "<f9>" #'db/org-find-links-to-current-item)
   (bind-key "C-," #'mc/skip-to-previous-like-this)
   (bind-key "C-." #'mc/skip-to-next-like-this)
   (bind-key "C-;" #'iedit-mode)
@@ -715,7 +715,8 @@
              db/find-csv-in-org
              db/org-mark-current-default-task
              db/export-diary
-             db/org-copy-template-for-periodic-task))
+             db/org-copy-template-for-periodic-task
+             db/org-find-links-to-current-item))
 
 (use-package org
   :pin "gnu"
@@ -1333,7 +1334,19 @@
                 (apply orig-fun args)))
 
             (advice-add 'org-roam--update-file-name-on-title-change
-                        :around #'db/org-roam--no-titlechange-if-title-is-nil)))
+                        :around #'db/org-roam--no-titlechange-if-title-is-nil)
+
+            ;; `org-roam--id-link-face' apparently changes the matching data,
+            ;; resulting in `org-finalize-agenda' to fail while applying text
+            ;; properties to ID links; let's warp `save-match-data' around calls
+            ;; to it.
+
+            (defun db/save-match-data (orig-fun &rest args)
+              (save-match-data
+                (apply orig-fun args)))
+
+            (advice-add 'org-roam--id-link-face
+                        :around #'db/save-match-data)))
 
 (use-package org-ref
   :config (progn

site-lisp/db-org.el

@@ -592,6 +592,49 @@ This is done only if the value of this variable is not null."
           (org-icalendar-combine-agenda-files)
           (message "Exporting diary ... done.")))))))
 
+
+;;; Find items by link to current headline
+
+(defun db/org-find-items-linking-by-id (id custom-id)
+  "List all Org Mode items that link to ID.
+Uses `org-search-view' to conduct the actual search.  ID must be
+a UUID as generated by, e.g., `org-id-get-create', and CUSTOM-ID
+must consist of ASCII letters, numbers, and hyphens only.  Each
+of ID and CUSTOM-ID may be nil, but at least one of them must be
+not."
+  (unless (or (not id)
+              (and (stringp id)
+                   (string-match-p  "^[a-f0-9]\\{8\\}-[a-f0-9]\\{4\\}-[a-f0-9]\\{4\\}-[a-f0-9]\\{4\\}-[a-f0-9]\\{12\\}$" id)))
+    (user-error "Given ID is not a valid UUID: %s" id))
+  (unless (or (not custom-id)
+              (and (stringp custom-id)
+                   (string-match-p "[-a-zA-Z0-9]" custom-id)))
+    ;; sorry, only ASCII right now …
+    (user-error "CUSTOM_ID must consist of alphanumeric charaters only"))
+
+  (let ((query (cond
+                ((and id custom-id) (format "{\\[\\[id:%s\\]\\|\\[\\[#%s\\]}" id custom-id))
+                (id (format "[[id:%s]" id))
+                (custom-id (format "[[#%s]" custom-id))
+                (t (user-error "No ID given and not in Org Mode.")))))
+    (org-search-view nil query)))
+
+(defun db/org-find-links-to-current-item (arg)
+  "Find links to current item.
+Only links using the ID or CUSTOM_ID property are considered.
+
+If ARG is given, or if not in an Org Mode buffer, interactively
+prompt for an item."
+  (interactive "P")
+  (apply #'db/org-find-items-linking-by-id
+         (if (and (derived-mode-p 'org-mode) (not arg))
+             (list (org-id-get) (org-entry-get nil "CUSTOM_ID"))
+           (let ((pom (nth 3 (org-refile-get-location nil (get-file-buffer db/org-default-org-file)))))
+             (if (not pom)
+                 (user-error "Invalid location")
+               (org-with-point-at pom
+                 (list (org-id-get) (org-entry-get nil "CUSTOM_ID"))))))))
+
 
 ;;; End