Remove key binding from `ess-extra-map`

Question

Related:

• https://stackoverflow.com/questions/7598433/how-to-remove-a-key-from-a-minor-mode-keymap-in-emacs
• How can I find out in which keymap a key is bound?

There is a default key binding in ESS that I accidentally trigger periodically: C-c C-e r calls inferior-ess-reload which kills and restarts my running R process. (It is close-enough to C-c C-e w ess-execute-screen-options that my finger might tap the R key.)

I know the map to which it is assigned (https://github.com/emacs-ess/ESS/blob/master/lisp/ess-mode.el#L115). I'm trying to add an unbind to a package hook, either of

(define-key ess-extra-map "\C-c\C-er" nil)
(define-key ess-extra-map (kbd "C-c C-e r") nil)

but after running those commands, C-h b and C-h C-k C-c C-e r confirm that it is still bound.

A third option would be to just comment-out those lines in ess-mode.el, but that won't survive updates.

Is there a better way to do it?

GNU Emacs 26.2 (build 1, x86_64-w64-mingw32) of 2019-04-13
ess-version: 18.10.3snapshot [elpa: 20190814.1054] (loaded from c:/Users/r2/.emacs.d/elpa/ess-20190814.1054/)

---

Update 1

From Drew's suggestion, here is the relevant portion of C-h b, filtering for C-c C-e:

Key translations:
key             binding
---             -------
...
C-c C-b         ess-eval-buffer
C-c C-c         ess-eval-region-or-function-or-paragraph-and-step
C-c C-d         ess-doc-map
C-c C-e         ess-extra-map
C-c C-f         ess-eval-function
...

C-c C-e C-c     Prefix Command
C-c C-e C-d     ess-dump-object-into-edit-buffer
C-c C-e C-e     ess-execute
C-c C-e TAB     ess-install-library
C-c C-e C-l     ess-load-library
C-c C-e C-r     inferior-ess-reload
C-c C-e C-s     ess-set-style
C-c C-e C-t     ess-build-tags-for-directory
C-c C-e C-w     ess-execute-screen-options
C-c C-e /       ess-set-working-directory
C-c C-e C       Prefix Command
C-c C-e d       ess-dump-object-into-edit-buffer
C-c C-e e       ess-execute
C-c C-e i       ess-install-library
C-c C-e l       ess-load-library
C-c C-e r       inferior-ess-reload
C-c C-e s       ess-set-style
C-c C-e t       ess-build-tags-for-directory
C-c C-e w       ess-execute-screen-options

...


Global Bindings:
key             binding
---             -------

...
C-c C-e         Prefix Command
...

I'm not certain why C-c C-e is shown in both "Key translations" and "Global Bindings", is that an issue?

Answer 1

I think you are looking for this:

(define-key ess-extra-map "r" nil)

Not this:

(define-key ess-extra-map (kbd "C-c C-e r") nil)

C-c C-e is bound to a keymap. In that keymap, r is bound to inferior-ess-reload.