On Sun, Jun 18 2017, Timothy Sample wrote:
> While the user experience would suffer a bit, it’s no real hardship to
> type
>
>     $ guix package \
>         --do-not-upgrade $(guix package --only-substitutes -u) \
>         -u
>
> This is definitely possible.

Just checking: is the proposal that --only-substitutes /always/ prints a
list of packages without substitutes? My understanding was that it would
only print the list if there were packages without substitutes (thus
making the above potentially incorrect/wasteful if everything has a
substitute, because you shouldn't unconditionally re-run `guix
package`). I don't know if we should conflate "upgrade my profile" with
"print a list of packages without substitutes". Those aren't the same
requests.

I'm more in favour of it continuing and building the new profile, but
printing a list of packages which didn't have substitutes. If the user
wants to roll-back the upgrade then they can easily do so, but they
asked for it to be upgraded and we can still do that.

Carlo