Re: [PATCH] gnu: r: Update to 3.3.1.

[Roel Janssen <roel@gnu.org>]

myglc2 writes:

> Pjotr Prins <pjotr.public12@thebird.nl> writes:
>
>> On Sat, Jul 30, 2016 at 03:41:50PM -0400, myglc2 wrote:
>>> The workaround used by sysops where I work (hospital research lab) is to
>>> give notice of R upgrades and to make previous releases available for
>>> reference by ongoing projects. IMO, we should consider how the guix R
>>> recipe(s) might support a pattern of use like this.
>>> 
>>> I can assure you that if our users do guix pull and invisibly get a new
>>> R release, their analyses will from time to time break. So we may want a
>>> simple way for them to back down to a previous release. So.. I am
>>> thinking it would make sense to keep previous versions of R in the
>>> recipe. What do others think?
>
>> Note, meanwhile, that a new R install does not remove the old packages
>> automatically. One way to work older versions is by using guix
>> profiles effectively. We introduced Unix modules with Guix, so a
>> module would point to a well tested and working profile. Just make
>> sure it does not get GC'd at some point.
>
> This functionality could be adequate in some situations if it can be
> made simple to use. Some questions to answer...
>
> What do you mean by "Unix modules"?

I think Pjotr means environment variables.

> How does one "make sure it does not get GC'd"?

Keep it in a profile linked to the store.  (So once you've installed
a version in a profile, Guix will not GC it as long as you haven't
removed the profile, or the programs in the profiles and its
accompanying generations).

> What happens when a user wants something else (e.g., not R) updated?

He can just to `guix package --upgrade=<specific-package>'.

>> Another way to work it is by using a checked out Guix source tree.
>
> This is not simple and is beyond the capability of the medical
> researchers I have met.

I agree.  However, when upgrading packages, they can be careful not to
upgrade a package.  You can do that by `guix package --upgrade
--do-not-upgrade=r'.

This may seem too difficult as well, but let's consider the alternative:
Not upgrading packages upstream.  That's what we can already do
downstream (simply don't run `guix pull').  I like having the latest
versions available in GNU Guix, and when I need an older version, I can
find it in the version control system.

Kind regards,
Roel Janssen