docs: keep the org-element cache reproduction evidenceHEADmain

Twelve scripts plus a README covering the persist-write cache corruption:
the no-dirvish root cause, the buffer-list ordering dependency, a faithful
replay of the file-manager preview path, and the two fixes I tried and
reverted.

The README says which scripts are weak evidence and why, so the next reader
doesn't rebuild an argument on the one whose control varied three things at
once.

Also holds the upstream bug report and its reproduction, verified to run
standalone under emacs -Q.

1 files changed, 48 insertions, 0 deletions

diff --git a/working/org-element-cache-persist-bug/hostile-d-faithful.el b/working/org-element-cache-persist-bug/hostile-d-faithful.el
new file mode 100644
index 00000000..bbd0aecb
--- /dev/null
+++ b/working/org-element-cache-persist-bug/hostile-d-faithful.el
@@ -0,0 +1,48 @@
+;; 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))