[Bug] org-persist.el: xdg.el is unavailable in emacs-25.2

[Bug] org-persist.el: xdg.el is unavailable in emacs-25.2

[Max Nikulin]

Org-mode compilation fails with the following errors if emacs-25.2.2 is 
used (Ubuntu-18.04 LTS bionic)

> Compiling /home/ubuntu/org-mode/lisp/ox-ascii.el...
> 
> In toplevel form:
> ox-ascii.el:31:1:Error: Cannot open load file: No such file or directory, xdg
> Compiling /home/ubuntu/org-mode/lisp/ox-beamer.el...
> 
> In toplevel form:
> ox-beamer.el:34:1:Error: Cannot open load file: No such file or directory, xdg
 >
 > ...

org.el in the main branch still declares

> ;; Package-Requires: ((emacs "25.1"))

but it seems xdg.el used by org-persist.el was added in emacs-26.0.

I do not actually use emacs-25.2, but it happened that I have a test 
container for Org based on Ubuntu-18.04.

Either org-persist and org-compat should be updated with some 
compatibility code or required emacs version should be updated once more.

Re: [Bug] org-persist.el: xdg.el is unavailable in emacs-25.2

[Ihor Radchenko]

Max Nikulin <manikulin@gmail.com> writes:

>> In toplevel form:
>> ox-beamer.el:34:1:Error: Cannot open load file: No such file or directory, xdg
>  >
>  > ...
>
> org.el in the main branch still declares
>
>> ;; Package-Requires: ((emacs "25.1"))
>
> but it seems xdg.el used by org-persist.el was added in emacs-26.0.
>
> I do not actually use emacs-25.2, but it happened that I have a test 
> container for Org based on Ubuntu-18.04.
>
> Either org-persist and org-compat should be updated with some 
> compatibility code or required emacs version should be updated once more.

Technically, the current Emacs version is Emacs 27. So, following our
maintenance convention [1], we should support everything down to Emacs
25 (e.g. 27-2). However, Emacs 28 is going to be out soon-ish and the
problem is not on bugfix branch, but only on main. I am not sure if we
need to follow version-2 convention for main as well. Maybe better
require only version-1? Weaker back-compatibility requirement can allow
us to implement more advanced features relying on more recent Emacs
versions.

[1] https://orgmode.org/worg/org-maintenance.html

Also, org-src.el from bugfix may not run on Emacs 25:

In end of data:
org-src.el:1312:1:Warning: the function ‘replace-buffer-contents’ is not known
    to be defined.

Best,
Ihor

Re: [Bug] org-persist.el: xdg.el is unavailable in emacs-25.2

[Ihor Radchenko]

Ihor Radchenko <yantar92@gmail.com> writes:

>> org.el in the main branch still declares
>>
>>> ;; Package-Requires: ((emacs "25.1"))

This is no longer relevant. We only support Emacs 26+.
Canceled.

We will be dropping Emacs 26 as well once we start seeing breakage
(Emacs 29 is the newest Emacs as for now, and we only officially support
Emacs 29-2=27). Now, Emacs 26 is working while it is working. No special
effort to keep things for Emacs 26.

-- 
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>