bug#62762: 'make' often errors with "Org version mismatch" after pulling a new version of the code

[Alan Mackenzie <acm@muc.de>]

Hello, Ihor.

It occurs to me that perhaps the CC Mode solution to the original
problem might be useful.  It was written by my predecessor at CC Mode,
Martin Stjernholm.  In ~20 years of using it, I've never had problems
with using incorrect versions of macros, or anything like that.

To quote part of the commentary from lisp/progmodes/cc-bytecomp.el:

;; This file is used to ensure that the CC Mode files are correctly
;; compiled regardless the environment (e.g. if an older CC Mode with
;; outdated macros are loaded during compilation).  It also provides
;; features to defeat the compiler warnings for selected symbols.

It works by pushing the correct directories onto load-path at the start
of each compilation, and popping them off again at the end.

Feel free to consider using this approach!

-- 
Alan Mackenzie (Nuremberg, Germany).



On Wed, May 03, 2023 at 10:30:55 +0000, Ihor Radchenko wrote:
> Stefan Monnier <monnier@iro.umontreal.ca> writes:

> >> This looks interesting, if we replace all the requires in Org with
> >> `my-require-with-shadow-check'.
> >
> > If we make it signal an error, then I think we only need it for the
> > requires that load "the one first file" (which you suggest could be
> > `org-macs.el`).

> This might work.

> Max, do you see any obvious downsides in Stefan's idea about consulting
> `load-history' vs. `load-path'?

> >> Although, AFAIU, it does not address the problem with stale .elc files
> >> kept from the previous Org version in the same folder (AFAIR, it is what
> >> often happens in ELPA builds).
> >
> > I don't understand what you mean here: when `package.el` compiles the
> > files of the Org package, that package has just been untarred into
> > a fresh new directory, so there should never be any stale `.elc` files
> > in there.

> I am referring to https://orgmode.org/list/jwvsfkv5s7l.fsf-monnier+emacs@gnu.org

> >> And we somehow need to make sure that `my-require-with-shadow-check' is
> >> available for all its users.
> >
> > Ah, the fun of bootstrapping :-)

> I guess that the cleanest way could be putting
> `require-with-shadow-check' into a new file. Then, we have no chance of
> this file being loaded by old Org version.

> -- 
> 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>