[POLL] Should we accept breaking changes to get rid of Org libraries that perform side effects when loading? (was: org-ctags land grab)

[Ihor Radchenko]

Max Nikulin <manikulin@gmail.com> writes:

>> Sure. This is not by itself a big deal. A number of Elisp libraries,
>> including built-in Emacs libraries are loaded with side effects.
>
> It is still violation of conventions:
>
> (info "(elisp) Coding Conventions")
> https://www.gnu.org/software/emacs/manual/html_node/elisp/Coding-Conventions.html
>> D.1 Emacs Lisp Coding Conventions
>> 
>> Simply loading a package should not change Emacs’s editing behavior.
>> Include a command or commands to enable and disable the feature, or to
>> invoke it.
>> 
>> This convention is mandatory for any file that includes custom
>> definitions. If fixing such a file to follow this convention requires an
>> incompatible change, go ahead and make the incompatible change; don’t
>> postpone it.

This is convincing.
I am then CCing Bastien, as, despite the Elisp convention, following it
will break https://bzg.fr/en/the-software-maintainers-pledge/

>> Note that we discussed loading side effects in
>> https://list.orgmode.org/orgmode/tn4ql0$bu2$1@ciao.gmane.io/
>
> I have not responded to that thread. My opinion is that besides 
> functions that just loads files and packages there should be 
> counterparts that loads and activates libraries. A proof of concept may 
> be implemented for Org and in the case of success it may be proposed for 
> inclusion into Emacs core.

Maybe. We can do something similar to `unload-feature'. However, it will
still require users to adapt.

Tentative implementation:

(defun enable-feature (feature &optional filename noerror)
  "Load and enable FEATURE.
FILENAME and NOERROR arguments are the same as in `require'."
  (when (require feature filename noerror)
    (let ((enabler-cmd (intern (format "%s-enable-function" feature))))
      (and (fboundp enabler-cmd) (funcall enabler-cmd)))))

(defun disable-feature (feature)
  "Disable FEATURE."
  (let ((disabler-cmd (intern (format "%s-disable-function" feature))))
    (and (fboundp disabler-cmd) (funcall disabler-cmd))))

-- 
Ihor Radchenko // yantar92,
Org mode contributor,
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