Re: Principled Handling of Breaking Changes

[Ihor Radchenko <yantar92@posteo.net>]

Rudi C <rudiwillalwaysloveyou@gmail.com> writes:

>> what other breaking changes caused problems for you?
>
> I remember these three:
>
> - `tab-width`
> - fontification in example blocks (
> https://git.savannah.gnu.org/cgit/emacs/org-mode.git/commit/?id=9daad41cc)
> - `org-fold-core-style` changing to `text-properties` (from `overlays`)
> broke custom code I had for coloring links.

I think I need to clarify a bit about how we consider changes in Org mode.

- We rarely touch default values in user customization - same as what
  Emacs does. Every time we do go ahead with changing customization
  defaults, we consider such a change very carefully.

  Changing tab-width has a strong justification - we are aiming to
  stabilize Org mode markup and register it officially. So, all aspects
  of Org markup will eventually be decoupled from Emacs customization.
  (the other question is whether we can avoid co-lateral damage; let's
  discuss it in the other thread)

- We reserve the right to change internal implementation details of Org
  mode at will. Like the details how folding is implemented. Any other
  policy would make it impossible to add new and improve existing
  features of Org mode. Emacs has the same policy.

  Yet, we take care to communicate major changes in the internals to
  users who might be relying upon implementation details.

- We also reserve the right to alter undocumented features of Org mode.
  We do not exercise this right at will though - if we can keep some
  undocumented feature without too much effort, we do.

  Example block fontification was one of the undocumented features. As
  per the commit you linked to, we restored example block fontification
  and added a comment in the code to avoid future accidental breakage
  upon reporting.

>> The very first section in https://orgmode.org/Changes.html lists
>> breaking and important changes.
>
> I don't care about "important changes" though, I just want the breaking
> changes ... I guess I should allocate the needed time for reading this
> anyway.

The exact name of the section is "Important announcements and breaking
changes". By "important announcements", we really mean important -
something that may need action. For example, changes in folding
machinery where not breaking (they did not break any documented
feature), but certainly important enough to bring to everyone's
attention.

-- 
Ihor Radchenko // yantar92,
Org mode contributor,
Learn more about Org mode at <https://orgmode.org/>.
Support Org development at <https://liberapay.com/org-mode>,
or support my work at <https://liberapay.com/yantar92>