Re: Confused by y-or-n-p

[Tassilo Horn]

Eli Zaretskii <eliz@gnu.org> writes:

> Not sure we are on the same page.  I meant the following situation:
>
>   . I installed foobar, which brought me foobar-7.1.0, the latest
>     version at that time
>   . Time passes and I learn there's a newer version of foobar, 8.1.0.
>     So I install foobar again, and that brings me foobar-8.1.0.
>
> But did installing foobar-8.1.0 remove the installation of
> foobar-7.1.0?

Yes.  Indeed the emacs package (on my Arch install) installs both
/usr/bin/emacs and /usr/bin/emacs-27.1 so it could keep the old version
of the binary around, and also the lisp in /usr/share/emacs/27.1/.  But
then the question is when and how are those files eventually going to be
removed?  And what about the files in /usr/share/emacs/site-lisp/?  If
they were byte-compiled with the newer version, is there a guarantee
they'll work in all the older versions?

> Do distros forcibly remove those versioned files and directories when
> they install a new version?

Yes, as said.  Usually the package manager has some database of
package-<version> and the files it installed and will remove the files
when the package version is removed in order to clean up.

>> And from a distro packager's point of view, the additional
>> user-convenience of enabling users to compare emacs version X against
>> the current version surely doesn't justify the added maintenance
>> costs.
>
> In the case of Emacs, I see no additional costs if all they do is
> refrain from removing the files belonging to the previous versions.
> The costs are of the end-user.

They'd probably still receive bug reports for the old version.

Bye,
Tassilo