(highlight-changes-rotate-faces): Don't set modified flag of buffer.

Use `inhibit-modification-hooks'.

diff --git a/lisp/hilit-chg.el b/lisp/hilit-chg.el
index c867bcfaf08f734104f547033ee682e61faef004..19cecb1c8be8ec7cbce838878af531f105487dd4 100644 (file)
--- a/lisp/hilit-chg.el
+++ b/lisp/hilit-chg.el
@@ -790,17 +790,37 @@ this, eval the following in the buffer to be saved:
   (interactive)
   ;; If not in active mode do nothing but don't complain because this
   ;; may be bound to a hook.
-  (if (eq highlight-changes-mode 'active)
-      (let ((after-change-functions nil))
-       ;; ensure hilit-chg-list is made and up to date
-       (hilit-chg-make-list)
-       ;; remove our existing overlays
-       (hilit-chg-hide-changes)
-       ;; for each change text property, increment it
-       (hilit-chg-map-changes 'hilit-chg-bump-change)
-       ;; and display them all if active
-       (if (eq highlight-changes-mode 'active)
-           (hilit-chg-display-changes))))
+  (when (eq highlight-changes-mode 'active)
+    (let ((modified (buffer-modified-p))
+         (inhibit-modification-hooks t))
+      ;; The `modified' related code tries to combine two goals: (1) Record the
+      ;; rotation in `buffer-undo-list' and (2) avoid setting the modified flag
+      ;; of the current buffer due to the rotation.  We do this by inserting (in
+      ;; `buffer-undo-list') entries restoring buffer-modified-p to nil before
+      ;; and after the entry for the rotation.
+      (unless modified
+       ;; Install the "before" entry.
+       (setq buffer-undo-list
+             (cons '(apply restore-buffer-modified-p nil)
+                   buffer-undo-list)))
+      (unwind-protect
+         (progn
+           ;; ensure hilit-chg-list is made and up to date
+           (hilit-chg-make-list)
+           ;; remove our existing overlays
+           (hilit-chg-hide-changes)
+           ;; for each change text property, increment it
+           (hilit-chg-map-changes 'hilit-chg-bump-change)
+           ;; and display them all if active
+           (if (eq highlight-changes-mode 'active)
+               (hilit-chg-display-changes)))
+       (unless modified
+         ;; Install the "after" entry.
+         (setq buffer-undo-list
+               (cons '(apply restore-buffer-modified-p nil)
+                     buffer-undo-list))
+
+         (restore-buffer-modified-p nil)))))
   ;; This always returns nil so it is safe to use in write-file-functions
   nil)