Re: Bug? org-assert-version does not prevent mixed install

[Max Nikulin]

On 18/12/2022 21:26, Ihor Radchenko wrote:
> Max Nikulin writes:
>
> > > We might do something like
> > >
> > > (eval-and-compile (org-assert-version))
> >
> > This will give obscure error during compiling since `org-assert-version'
> > is not defined.
>
> Yes, but we will at least abort the compilation this way.

You are right that it prevents creation of .elc files. Unfortunately 
`byte-recompile-directory' converts failure into a message instead of 
aborting package install completely.

When used consistently, it should cause load of Org completely 
uncompiled during next Emacs session. It is better than having 
incorrectly compiled files.

Notice that `org-assert-version' works for compiled files only, so if a 
user loads some third-party package (hyperbole?) that loads built-in Org 
and later adds new Org to `load-path' then we get an obscure error again.

Currently I am experimenting with minimal examples, not with full Org 
package, so I may confuse something.

> > ;; Remove when support of Emacs-29 is dropped.
> > (unless (fboundp 'org-assert-version)
> >     (error "Org is compiled or loaded while older version loaded already.
> >    Please, ensure that no other org versions are loaded and recompile."))

Another idea to have more concise code in each file is to put a new 
macro to a *new* file to avoid the issue with old org-macs.el without 
definition of the new macro `org-assert-version'. So each file should 
contain

(require 'org-assert-version-undefined)
(org-assert-version-undefined)

`org-assert-version' remains in org-macs.el. The goal is to generate an 
instructive error. The problem is that after fix in 
org-assert-version-undefined.el, an old version will be active for some 
users.

In addition I have noticed that e.g. org-matlab.el contains

     (require 'org-macs)
     (org-assert-version)

Shouldn't it be (eval-when-compile (require 'org-macs)) since no 
functions are used from this file? Some files have duplicated (require 
'org-macs).