(hexlify-buffer, dehexlify-buffer): Clear out the undo

info, and don't record undo info for the conversion.

1 files changed, 16 insertions, 4 deletions

diff --git a/lisp/hexl.el b/lisp/hexl.el
index 9cf768248c3..d804d5b514f 100644
--- a/lisp/hexl.el
+++ b/lisp/hexl.el
@@ -554,17 +554,29 @@ You may also type up to 3 octal digits, to insert a character with that code"
 
 ;;;###autoload
 (defun hexlify-buffer ()
-  "Convert a binary buffer to hexl format."
+  "Convert a binary buffer to hexl format.
+This discards the buffer's undo information."
   (interactive)
+  (and buffer-undo-list
+       (or (y-or-n-p "Converting to hexl format discards undo info; ok? ")
+           (error "Aborted")))
+  (setq buffer-undo-list nil)
   (let ((binary-process-output nil) ; for Ms-Dos
-        (binary-process-input t))
+        (binary-process-input t)
+        (buffer-undo-list t))
     (shell-command-on-region (point-min) (point-max) hexlify-command t)))
 
 (defun dehexlify-buffer ()
-  "Convert a hexl format buffer to binary."
+  "Convert a hexl format buffer to binary.
+This discards the buffer's undo information."
   (interactive)
+  (and buffer-undo-list
+       (or (y-or-n-p "Converting from hexl format discards undo info; ok? ")
+           (error "Aborted")))
+  (setq buffer-undo-list nil)
   (let ((binary-process-output t) ; for Ms-Dos
-        (binary-process-input nil))
+        (binary-process-input nil)
+        (buffer-undo-list t))
     (shell-command-on-region (point-min) (point-max) dehexlify-command t)))
 
 (defun hexl-char-after-point ()