Fix nil display in agenda when remaining effort is not set

Just return the empty string instead.

init.el

@@ -730,6 +730,8 @@
              db/org-clock-in-home-task
              db/org-clock-in-work-task
              db/show-current-org-task
+             db/org-remaining-effort-of-current-item
+             db/org-cmp-remaining-effort
              org-dblock-write:db/org-workload-report
              endless/org-ispell
              db/org-agenda-list-deadlines
@@ -1100,10 +1102,11 @@
   :init (setq org-agenda-include-diary t
               org-agenda-span 1
               org-agenda-insert-diary-strategy 'top-level
-              org-agenda-sorting-strategy '((agenda time-up priority-down effort-up category-keep)
-                                            (todo priority-down effort-up category-keep)
-                                            (tags priority-down effort-up category-keep)
-                                            (search priority-down effort-up category-keep))
+              org-agenda-sorting-strategy '((agenda time-up priority-down user-defined-up category-keep)
+                                            (todo priority-down user-defined-up category-keep)
+                                            (tags priority-down user-defined-up category-keep)
+                                            (search priority-down user-defined-up category-keep))
+              org-agenda-cmp-user-defined #'db/org-cmp-remaining-effort
               org-agenda-window-setup 'current-window
               org-agenda-restore-windows-after-quit t
               org-agenda-compact-blocks nil
@@ -1156,10 +1159,10 @@
                 "")
 
               org-agenda-prefix-format
-              '((agenda . "%11s%?-12t%-4e ")
-                (todo . "%-8c%-4e ")
-                (tags . "%-8c%-4e ")
-                (search . "%-8c%-4e "))
+              '((agenda . "%11s%?-12t%-4(db/org-remaining-effort-of-current-item) ")
+                (todo . "%-8c%-4(db/org-remaining-effort-of-current-item) ")
+                (tags . "%-8c%-4(db/org-remaining-effort-of-current-item) ")
+                (search . "%-8c%-4(db/org-remaining-effort-of-current-item) "))
 
               org-agenda-custom-commands
               `(("A" "Main Agenda"

site-lisp/db-org.el

@@ -204,7 +204,9 @@ shown because they are due)."
                         '("scheduled" "past-scheduled" "timestamp" "deadline" "block"))
             (let ((item-id (org-with-point-at (org-get-at-bol 'org-hd-marker) (org-id-get-create))))
               (unless (member item-id already-seen)
-                (push (org-entry-get (org-get-at-bol 'org-hd-marker) "Effort") total)
+                (push (org-with-point-at (org-get-at-bol 'org-hd-marker)
+                        (db/org-remaining-effort-of-current-item))
+                      total)
                 (push item-id already-seen))))
           (forward-line))))
     (org-duration-from-minutes
@@ -425,21 +427,52 @@ is clocked in."
 The remaining effort is computed as the planned effort minus the
 already clocked time.  If this result is negative, return zero.
 
-If no effort is specified, return nil."
+If no effort is specified, return an empty string."
 
   (if (derived-mode-p 'org-agenda-mode)
 
-      ;; XXX: is this the right way to do it?
-      (org-agenda-with-point-at-orig-entry
-       nil (db/org-remaining-effort-of-current-item))
+      (if-let ((hd-marker (org-get-at-bol 'org-hd-marker)))
+          ;; `org-hd-marker' is set, there is some Org item that corresponds to
+          ;; this line.  Get the remaining effort from there.
+          (org-with-point-at hd-marker
+            (db/org-remaining-effort-of-current-item))
+        ;; We are at some special item in the Org agenda (e.g. some diary
+        ;; entry), just show nothing.
+        "")
 
     (unless (derived-mode-p 'org-mode)
       (user-error "Not in Org mode buffer, aborting"))
 
-    (when-let ((effort (org-entry-get (point) "Effort")))
-      (org-duration-from-minutes
-       (max 0 (- (org-duration-to-minutes effort)
-                 (db/org-clocked-time-for-current-item)))))))
+    (if-let ((effort (org-entry-get (point) "Effort")))
+        (org-duration-from-minutes
+         (max 0 (- (org-duration-to-minutes effort)
+                   (db/org-clocked-time-for-current-item))))
+      "")))
+
+(defun db/org-cmp-remaining-effort (a b)
+  "Compare the remaining efforts of Org items A and B.
+
+A and B are strings only, but their corresponding Org items are
+accessible via the `org-hd-marker' text property."
+  (let* ((def (if org-agenda-sort-noeffort-is-high 32767 -1))
+         (ma (or (get-text-property 1 'org-marker a)
+                 (get-text-property 1 'org-hd-marker a)))
+         (mb (or (get-text-property 1 'org-marker b)
+                 (get-text-property 1 'org-hd-marker b)))
+         (ea (or (and (markerp ma)
+                      (marker-buffer ma)
+                      (org-with-point-at ma
+                        (org-duration-to-minutes ; this is inefficient
+                         (db/org-remaining-effort-of-current-item))))
+                 def))
+         (eb (or (and (markerp mb)
+                      (marker-buffer mb)
+                      (org-with-point-at mb
+                        (org-duration-to-minutes
+                         (db/org-remaining-effort-of-current-item))))
+                 def)))
+    (cond ((> ea eb) +1)
+          ((< ea eb) -1))))
 
 
 ;;; Task Management