Minor mode to allow users to override the builtin `notifications-notify` command with `alert`?

[gsingh93]

An issue I've come across in a few different packages now is that they use the builtin notifications library. But as far as I know, this doesn't work on macOS. As suggested here, this can be solved with define-advice:

(define-advice notifications-notify
    (:override (&rest params) using-alert)
  (alert (plist-get params :body)
         :title (plist-get params :title)))

In that same comment, the author suggested a minor-mode that would enable this configuration for you. What do you think about this? While I could just copy this snippet into my config, I feel like this affects a wide variety of packages and users, so a minor mode might make sense.

[LemonBreezes]

I just used AI to write an advice for this and it seems to work at first glance:

;; A flag to avoid recursive/advice reentry.
(defvar cae-notifications-advice-active nil
  "Non-nil if our notifications-notify advice is already active.
This prevents our advice from recursively intercepting internal calls.")

;; A little helper to remove a property from a plist.
(defun cae-plist-delete (plist key)
  "Return a copy of PLIST with KEY (and its value) removed."
  (let (result)
    (while plist
      (if (eq (car plist) key)
          (setq plist (cddr plist))
        (push (pop plist) result)
        (push (pop plist) result)))
    (nreverse result)))

;;;###autoload
(defun cae-notifications-notify-advice (orig-fun &rest args)
  "Advice for notifications-notify to adapt its keyword arguments for alert.
This advice transforms as many keywords as possible:

  • :body        → :message
  • :app-icon    → :icon
  • :urgency     → if :severity is not set, map its value to a severity
  • :actions, :on-action, :on-close, :timeout, and :replaces-id
     are removed from the top level and merged into the :data plist.
Additionally, any keys not part of the recognized alert parameter set
are merged into :data so that none of the diagnostic or extra keys is lost.
If the advice is active (e.g. when alert internally calls notifications-notify),
the original function is used."
  (if cae-notifications-advice-active
      (apply orig-fun args)
    (let ((cae-notifications-advice-active t))
      (let* ((plist (apply #'list args))
             (info  plist))
        ;; 1. Convert :body to :message (alert expects a message).
        (when (plist-get info :body)
          (setq info (plist-put info :message (plist-get info :body)))
          (setq info (cae-plist-delete info :body)))
        ;; 2. Map :app-icon to :icon if not already provided.
        (when (plist-get info :app-icon)
          (unless (plist-get info :icon)
            (setq info (plist-put info :icon (plist-get info :app-icon))))
          (setq info (cae-plist-delete info :app-icon)))
        ;; 3. If there’s an :urgency key and no :severity, map urgency to severity.
        (when (and (plist-get info :urgency) (not (plist-get info :severity)))
          (setq info (plist-put info :severity
                                (pcase (plist-get info :urgency)
                                  ((or "critical" 'critical) 'urgent)
                                  ((or "low" 'low) 'low)
                                  ((or "normal" 'normal) 'normal)
                                  (_ 'normal)))))
        (setq info (cae-plist-delete info :urgency))
        ;; 4. Ensure a default title if none is provided.
        (unless (plist-get info :title)
          (setq info (plist-put info :title "Emacs Notification")))
        ;; 5. Ensure a default severity if still missing.
        (unless (plist-get info :severity)
          (setq info (plist-put info :severity 'normal)))
        ;; 6. For some extra keys (like :actions, :on-action, :on-close, :timeout, :replaces-id),
        ;;    remove them from the plist and merge them into the :data key.
        (dolist (key '(:actions :on-action :on-close :timeout :replaces-id))
          (when (plist-member info key)
            (let ((val (plist-get info key)))
              (setq info (cae-plist-delete info key))
              (setq info (plist-put info :data
                                    (append (plist-get info :data) (list key val))))))

          ;; 7. In case any extra keys remain (i.e. keys that are not part of alert’s parameters),
          ;;    merge them into the :data property.  The keys recognized by alert are:
          (let ((allowed-keys '(:message :title :icon :severity :category :buffer
                                :mode :persistent :never-persist :id :style :data))
                (final-info '())
                (extras '())
                (tmp info))
            (while tmp
              (let ((key (pop tmp))
                    (val (pop tmp)))
                (if (memq key allowed-keys)
                    (setq final-info (plist-put final-info key val))
                  (setq extras (plist-put extras key val)))))
            (when extras
              (setq final-info (plist-put final-info :data
                                          (append (plist-get final-info :data) extras))))
            ;; 8. Finally, call alert with the message (extracted from :message)
            ;;    and the rest of the keys as keyword arguments.
            (apply #'alert (cons (plist-get final-info :message)
                                 (cae-plist-delete final-info :message)))))))))