bug#63757: 29.0.91 order of package paths changed: random old versions of packages in load-path

[Ruijie Yu via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Евгений Бойков <artscan@list.ru>
>> Date: Sun, 4 Jun 2023 18:43:13 +1000
>> Cc: monnier@iro.umontreal.ca, philipk@posteo.net, 63757@debbugs.gnu.org
>> 
>> > I wonder how come this issue never came up until now, in all the time
>> > since commit fb87d500, 9 months ago?  What are you, Евгений, do that
>> > bumps into this issue, that other people don't do?  Or does this
>> > affect only very specific packages?
>> 
>> I moved my everyday working emacs instance to 29.0.91 and got almost 2% completely broken
>> packages.
>> I rarely delete really old versions from my ~/.emacs.d/elpa.
>> If your package-user-dir is cleaned more often, you may not notice that your loaded packages have
>> slightly different old versions.
>> This can affect any package if it has few versions.
>
> So you are saying that other people mostly delete old versions from
> ~/.emacs.d/elpa/, and that's why this problem was not reported until
> now, is that right?

IIRC, from another bug report, someone shared that pressing U in `M-x
list-packages' is equivalent to: "for each upgradable pacakge, install
the new version and uninstall the old version".

So, I think what Евгений did was go to the package list, find the new
version of a package of interest and install it -- _without_ also
deleting the old version.

> What are our recommendations, if any, for cleaning up old versions of
> ELPA packages?


-- 
Best,


RY