ox-icalendar.el: create alarm at event time

* lisp/ox-icalendar.el (org-icalendar-force-alarm): Option to set alarm even if alarm time is set to zero. * lisp/ox-icalendar.el (org-icalendar--valarm): create VALARM at the event start if the alarm time is set to zero and `org-icalendar-force-alarm' is set to true. TINYCHANGE

Author: mskorzhinskiy

lisp/ox-icalendar.el

@@ -69,6 +69,17 @@ for timed events. If non-zero, alarms are created.
  :version "24.1"
  :type 'integer)
 
+(defcustom org-icalendar-force-alarm nil
+ "Non-nil means alarm will be created even if is set to zero.
+
+This overrides default behaviour where zero means no alarm. With
+this set to non-nil and alarm set to zero, alarm will be created
+and will fire at the event start."
+ :group 'org-export-icalendar
+ :type 'boolean
+ :package-version '(Org . "9.6")
+ :safe #'booleanp)
+
 (defcustom org-icalendar-combined-name "OrgMode"
  "Calendar name for the combined iCalendar representing all agenda files."
  :group 'org-export-icalendar
@@ -795,17 +806,22 @@ Return VALARM component as a string, or nil if it isn't allowed."
  (let ((alarm-time
  (let ((warntime
 (org-element-property :APPT_WARNTIME entry)))
- (if warntime (string-to-number warntime) 0))))
- (and (or (> alarm-time 0) (> org-icalendar-alarm-time 0))
+ (if warntime (string-to-number warntime) nil))))
+ (and (or (and alarm-time
+ (> alarm-time 0))
+ (> org-icalendar-alarm-time 0)
+ org-icalendar-force-alarm)
  (org-element-property :hour-start timestamp)
  (format "BEGIN:VALARM
 ACTION:DISPLAY
 DESCRIPTION:%s
 TRIGGER:-P0DT0H%dM0S
 END:VALARM\n"
  summary
- (if (zerop alarm-time) org-icalendar-alarm-time alarm-time)))))
-
+ (cond
+ ((and alarm-time org-icalendar-force-alarm) alarm-time)
+ ((and alarm-time (not (zerop alarm-time))) alarm-time)
+ (t org-icalendar-alarm-time))))))
 
 ;;;; Template