ludo@gnu.org (Ludovic Courtès) writes:

> Mark H Weaver <mhw@netris.org> skribis:
>
>> Okay.  I was relying on the fact that attempts to install a derivation
>> that's already installed will ultimately be ignored, and my (admittedly
>> simple) tests seem to suggest that it works properly, but perhaps this
>> approach will be too inefficient when the profile contains a large
>> number of packages.
>
> More importantly, you don’t want upgrade to downgrade.

Ah, good point! :)

> For instance, if guile-1.8.8 turns out to be before guile-2.0.7 in the
> package list, users who’ve installed the latter shouldn’t suddenly
> downgrade to the former.

Would "guix-package -i guile" ever choose guile-1.8.8 over guile-2.0.7
if the latter was available?  Does it not automatically choose the
newest available version?  If not, should it?

> I’ll take care of the tests and -e.

Great, thanks!

I've attached a new implementation of --upgrade along the lines you
suggested.  Still remaining to be done: if there are multiple packages
with the same (newest) version number, choose intelligently between
them.

The first patch moves 'version-string>?' to (guix utils) and renames it
to 'version>?'.  It also adds 'version-compare'.  I needed these for the
improved upgrade implementation.

Comments and suggestions solicited.

     Mark