bug#69391: 30.0.50; `enable-command' doesn't permanently enable `help-fns-edit-variable'

[Eli Zaretskii <eliz@gnu.org>]

> From: Martin Marshall <law@martinmarshall.com>
> Date: Sun, 25 Feb 2024 12:44:01 -0500
> 
> Description:
> 
> When initially calling `help-fns-edit-variable', the disabled command
> pop-up appears.  There's a prompt to enable the command, and pressing
> "y" does so for the current session.  Thereafter, a second message
> appears in the minibuffer advising to press "y" again to enable the
> command in future sessions.  However, this does not have the described
> effect.
> 
> Pressing "y" adds "(put 'help-fns-edit-variable 'disabled nil)" to the
> end of `user-init-file'.  However, after restarting Emacs, attempting to
> invoke the command again brings up the same "disabled command" pop-up.
> 
> Recreating:
> 
> 1.  Create directory for testing,
>     cd; mkdir emacs-test-disabled-cmds; cd emacs-test-disabled-cmds
> 2.  "touch init.el"
> 3.  "emacs --init-directory . &"
> 4.  "C-x b *scratch* RET"
> 5.  "(setopt help-enable-variable-value-editing t) C-x C-e"
> 6.  "C-h v electric-pair-mode RET"
> 7.  "C-x o" then move cursor to the `nil' value shown
> 8.  Press "e" to edit the variable value, a disabled-command pop-up
>     appears.
> 9.  Press "y" to "enable the command".
> 10. Press "y" again to enable it "for future editing sessions also".
> 11. Press "C-c C-c" to exit the variable-editing buffer.
> 12. Go back to the *Help* buffer and try to edit the variable again,
>     there is no pop-up, because the command has been enabled for this
>     session.
> 13. Press "C-x C-c" to exit Emacs.
> 14. "cat init.el" confirms that the init file does contain
>     "(put 'help-fns-edit-variable 'disabled nil)"
> 15. But when you repeat steps 3 through 8, you find that the disabled
>     command pop-up still appears.
> 
> Probable diagnosis:
> 
> It looks like most of Emacs's disabled commands are either set disabled
> in libraries that load before the init-file, or they are disabled via
> autoload cookies, like this one:
> 
>     ;;;###autoload (put 'dired-find-alternate-file 'disabled t)
> 
> But that's not the case for `help-fns-edit-variable' (and a few others,
> which I located using ripgrep).  So when "help-fns.el" loads, it
> re-disables the command that was supposed to have been enabled by the
> call to `put' that Emacs added to the init file.

Thanks for the analysis.

Stefan, is there a better way than convert the form we have in
help-fns.el:

   (put 'help-fns-edit-variable 'disabled t)

into an autoload comment, like we do, e.g., with
dired-find-alternate-file?