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, 32 insertions, 0 deletions

diff --git a/working/org-element-cache-persist-bug/hostile-c-repro.el b/working/org-element-cache-persist-bug/hostile-c-repro.el
new file mode 100644
index 00000000..17627e63
--- /dev/null
+++ b/working/org-element-cache-persist-bug/hostile-c-repro.el
@@ -0,0 +1,32 @@
+;;; -*- lexical-binding: t -*-
+(setq org-persist-directory (expand-file-name "hostile-c-persist" default-directory))
+(require 'org)
+(require 'org-element)
+(require 'org-persist)
+(let* ((f (expand-file-name "hostile-c-real.org" default-directory)))
+  (with-temp-file f (insert "* Head one\nbody\n* Head two\n"))
+  ;; 1. the REAL buffer, as Craig has open
+  (let ((real (find-file-noselect f)))
+    (with-current-buffer real (org-element-at-point (point-max)))
+    (princ (format "real registered: %S\n"
+                   (and (org-persist--find-index
+                         `(:container ,(org-persist--normalize-container
+                                        `((elisp org-element--cache) (version ,org-element-cache-version)))
+                           :associated ,(org-persist--normalize-associated real)))
+                        t)))
+    ;; 2. dirvish preview: second org buffer claiming the same file name
+    (let ((prev (get-buffer-create "PREVIEW :: hostile-c-real.org")))
+      (with-current-buffer prev
+        (insert-file-contents f)
+        (setq buffer-file-name f)
+        (delay-mode-hooks (org-mode))
+        ;; the commit's hook
+        (setq-local org-element-cache-persistent nil)
+        ;; 3. anything that resets the cache in this live preview buffer
+        (org-element-cache-reset))
+      (princ (format "real registered AFTER preview reset: %S\n"
+                     (and (org-persist--find-index
+                           `(:container ,(org-persist--normalize-container
+                                          `((elisp org-element--cache) (version ,org-element-cache-version)))
+                             :associated ,(org-persist--normalize-associated real)))
+                          t))))))