Re: Install older version of a package with the "@version" specifier

[Julien Lepiller]

Le 26 juin 2020 12:07:42 GMT-04:00, Lo Peter <peterloleungyau@gmail.com> a 
écrit :
>Dear all,
>
>I am trying to install r version 3.6.3, where the current version is at
>4.0.2.
>
>Accordingly to the manual at
>https://guix.gnu.org/manual/en/html_node/Invoking-guix-package.html it
>should be possible to specify the package version such as "guix
>package -i r@3.6.2", but on my guix (installed on slackware 14.2), it
>says:
>guix package: error: r: package not found for version 3.6.2
>
>What am I missing here?
>
>Regards,
>Peter

In general, at any point in time, we only keep one version of each packages. 
Exceptions are pretty rare (gcc, python, …). There two ways to get a version 
that's different from the one in the current guix:

- use the current guix and apply the recipe to an different version, by using 
something --with-source=r=r-3.6.3.tar.gz or similar. This is not guaranteed to 
work, as it applies the build procedure of version 4 to version 3. It uses 
recent software that are patched for vulnerability though.

- use r from an old revision of guix that had the version you're looking for. 
This can be done using an "inferior". The package will more likely build (and 
even have substitutes), but it uses the old version of all its dependencies, 
which are not necessarily patched for vulnerabilities and may require more 
space to be stored, as they are not shared with other packages.

HTH!