;; Faithful replay: real dirvish env incl. delay-mode-hooks, inhibit-message,
;; timestamped buffer name, preview-hash text reuse, dirvish--kill-buffer shape.
(require 'cl-lib) (require 'org) (require 'org-element) (require 'org-persist)
(when (getenv "FIX")
  (add-to-list 'load-path (expand-file-name "modules" default-directory))
  (require 'dirvish-config))
(setq org-element-use-cache t org-element-cache-persistent t)
(defvar hash (make-hash-table :test 'equal))
(defun nilbuf (b) (with-current-buffer b
  (let ((k 0)) (avl-tree-mapc (lambda (e) (unless (org-element-property :buffer e) (cl-incf k))) org-element--cache) k)))
(defun preview (file name)
  (with-current-buffer (get-buffer-create "*preview-temp*")
    (let ((text (gethash file hash)) info jka-compr-verbose)
      (with-silent-modifications
        (setq buffer-read-only t)
        (if text (insert text) (insert-file-contents file nil 0 1048576))
        (setq buffer-file-name file) (goto-char (point-min))
        (rename-buffer name))
      (condition-case err
          (eval `(let ((inhibit-message t) (non-essential t)
                       (enable-dir-local-variables nil) (enable-local-variables :safe))
                   (setq-local delay-mode-hooks t)
                   (set-auto-mode) (font-lock-mode 1)))
        (error (setq info (error-message-string err))))
      (if info (message ">> preview aborted: %s" info)
        (run-hooks 'dirvish-preview-setup-hook)
        (unless text (puthash file (buffer-string) hash)))
      (message ">> preview mode=%s delay-mode-hooks=%S persist=%S"
               major-mode delay-mode-hooks org-element-cache-persistent)
      (current-buffer))))
(defun dv-kill (b) (and (buffer-live-p b) (let (kill-buffer-query-functions) (kill-buffer b))))
(let* ((file (make-temp-file "fa-" nil ".org")))
  (copy-file (expand-file-name "todo.org" default-directory) file t)
  (let ((real (find-file-noselect file)))
    (with-current-buffer real (org-element-cache-map (lambda (_) nil) :granularity 'element))
    (message ">> real nil-buffer before=%d" (nilbuf real))
    ;; pass 1
    (dv-kill (preview file (format "PREVIEW :: %s :: %s" "1753000000" (file-name-nondirectory file))))
    (message ">> after pass1 kill nil-buffer=%d gfb=%S" (nilbuf real) (buffer-name (get-file-buffer file)))
    ;; pass 2 (hash hit: text branch)
    (dv-kill (preview file (format "PREVIEW :: %s :: %s" "1753000001" (file-name-nondirectory file))))
    (message ">> after pass2 kill nil-buffer=%d" (nilbuf real))
    (with-current-buffer real
      (goto-char (point-max))
      (condition-case err (let ((inhibit-read-only t)) (insert "\n* E\n"))
        (error (message ">> RESULT: SIGNALLED %S" err)))
      (message ">> edit completed") (set-buffer-modified-p nil)))
  (delete-file file))