Dear fellow emacsers.

How can we make undo work on the scratch buffer? I’m sure it is a simple configuration issue, but I’m not getting the appropriate keyword to find the relevant documentation.

Thanks a lot in advance for your help and attention…
:) /\

  • EduMercoOPEnglish
    1·
    11 months ago

    Maybe you can try to fix your issue by forcing the buffer-undo-list variable to nil for the elisp mode, as follow: (add-hook 'elisp-mode (lambda () (setq-local buffer-undo-list nil)))

    I tried it but still no joy…

    Looking at this issue I noticed 3 things that may help to pinpoint the origin…:

    • I have 2 variables set that affect the scratch buffer in my config (without yours, that it’s the 3rd):
                      (setq initial-major-mode 'org-mode)
                  (setq-default major-mode 'org-mode)
    • Before this reply, (setq-default major-mode 'org-mode) was (setq default-major-mode 'org-mode). Both expressions seems indistinguishable in the resulted behavior.
    • The scratch buffer starts in org-roam mode (and read-only mode), which is very strange, but can obviously be related and/or part of the problem. The org-roam section (my config is literate in org-mode) comes before this variables being set.

    What does this info may imply?

    • Sunoc@sh.itjust.worksEnglish
      1·
      11 months ago

      Okay, I could reproduce your situation by evaluating

      (setq initial-major-mode 'org-mode)
(setq-default major-mode 'org-mode)

      This setup forces the scratch buffer to be in org-mode, apparently breaking most of the available keybindings for it, including the undo.

      The value for the initial-major-mode should be kept as lisp-interaction-mode, if your configuration requires to set it.

      Otherwise I would remove both of these lines all together and see if the default behavior brings back the scratch buffer to be in the expected lisp-interaction-mode again. The additional hook I provided in my previous post shouldn’t be needed either.