bug#27820: guix package -u: order of argument is significant

[Mark H Weaver]

Hartmut Goebel <address@hidden> writes:

> I'm try upgrading from guix-0.12.0-10.ba2260d but the profile is not updated.
>
> I used "guix pull" to get the latest version.
>
> "guix package -u" is loading substitutes, fails with this and recommends
> using --fallback.
>
> "guix package -u --fallback" when run the first time did compile some
> packages, but did not update the profile.

That's because "--fallback" was treated as the argument to -u, i.e. the
regexp specifying which packages to upgrade.  The few compiled packages
were needed to run the profile hooks.

> "guix package -u --fallback" when run another time does *nothing*. "guix
> package -l" still show the old generation.

See above.  It did nothing this time because the packages needed to run
the profile hooks were already up-to-date.

> So I updated only guix "guix package -u guix", which gave me 
> guix-0.13.0-4.f1ddfe4.
>
>
> "guix package -u --fallback" when run another time again did nothing.
>
> BUT:
>
> "guix package --fallback -u" did upgrade the packages.

In this case, since there's no argument after -u, it implicitly upgrades
all packages.

When I want to add more options after -u, I add "." as the argument
after -u.

I agree that this is quite confusing.  Perhaps we should issue a warning
if the regexp begins with "-".

Also, perhaps we should *always* require an argument after "-u", even if
"-u" is at the end of the command line, failing otherwise.  Users would
then learn to always pass an argument to "-u", and thus would be less
likely to fall into this trap when adding more options after the "-u".

Thoughts?

      Mark