Re: cannot "guix pull"

[Sergiu Ivanov]

Thus quoth  Leo Famulari  on Mon Mar 22 2021 at 01:11 (+0100):
> I'm happy to help, but unfortunately, the paste that included the error
> messages is no longer online:
>
> https://lists.gnu.org/archive/html/help-guix/2021-03/msg00184.html
>
> This illustrates why it is important to include all relevant details of
> a problem in the email, rather than linking to external sites.
>
> Can any of you share the error messages, to refresh my memory?

I attach the complete error log as the plain text file
original-error-message.  It's the message I got today, but I think I got
the same or a very similar message a couple of days ago.  (And I didn't
save it because I thought it was transient.)

> I was hoping to use the following info to see if you were using a
> version of Guix that preceded a bug fix, but now I can't tell. I do
> think your bug has been fixed recently, and that `guix pull && sudo guix
> system reconfigure ...` will fix your problem, but I wanted to be sure.

Yaay!  It worked!

Not directly though: I did a `guix gc` first, because I seemed stuck on
the same error message all the time, then I had to run `guix pull`
multiple times, because I was getting different error messages.
I attach the files transient-error-1 and transient-error-2 to give some
examples, but I got about 5 or 6 of them in total.

guix pull did manage to finish successfully though, so I'm quite happy,
and I can live with occasional transient network issues.

`sudo guix system reconfigure /etc/config.scm` has showed some download
errors, but they consistently went away when I retried the command, so
that's fine.

Thank you the Guix team for working hard!

> Here are some general observations and advice:

Thank you very much for taking your time!

> On Sun, Mar 21, 2021 at 09:27:12AM +0100, Sergiu Ivanov wrote:
>> Thus quoth  Leo Famulari  on Sat Mar 20 2021 at 23:10 (+0100):
>> > $ guix describe
>> 
>> Generation 5    Mar 16 2021 10:31:09    (current)
>>   [blurred]
>>   guix db87d6d
>>     repository URL: https://git.savannah.gnu.org/git/guix.git
>>     branch: master
>>     commit: db87d6ddafd26c5ad657178cf7fdab524d05c522
>
> Okay. This is a recent version of Guix.
>
>> > $ sudo --login guix describe
>> 
>> Generation 1 Feb 02 2021 10:36:19    (current)
>>   [blurred]
>>   guix 625708b
>>     repository URL: https://git.savannah.gnu.org/git/guix.git
>>     branch: master
>>     commit: 625708b03a37fc2a33c437b8e27856ca76965f43
>
> This is probably the Guix at '/root/.config/guix/current/bin/guix'. That
> is the root user's Guix command, created and updated with `guix pull` as
> root. It's from early February.

Ah, just reading this paragraph fixed things in my brain.  I moved the
directory /root/.config/guix to some temporary place from where I will
delete it soon.

>>   $ sudo su
>>   $ guix describe
>> 
>> which gave me
>> 
>>     guix c8887a5
>>     repository URL: https://git.savannah.gnu.org/git/guix.git
>>     branch: master
>>     commit: c8887a5c6e8f6a19d54ffa428c6fe88a797b867a
>
> This is probably the system's Guix command, at
> '/run/current-system/profile/bin/guix'. It's recent.

Yes!  After moving /root/.config/guix away, both `sudo --login guix
describe` and first doing `sudo su` and then `guix describe` give me the
same results, probably because both are running the same system's
Guix command.

I was quite confused by getting different results in these two cases,
and I really happy to have sorted this out.  (Also, later in this
message I learnt something about sudo and su :-))

> Based on this, I guess you are updating the system by `guix pull` as
> your regular user and then `sudo guix system reconfigure ...`. Is that
> correct?

Yes, exactly.

I once accidentally did `sudo guix pull`, which brought in that extra
Guix in /root/.config/guix, but I don't normally do that.

> The different results between those two sudo commands shows an important
> and confusing issue with privilege elevation on Linux:
>
> There is a difference between plain `sudo` and `sudo --login`.
>
> `su` is an entirely different command, and it also does something
> different than `su --login`.
>
> Basically, plain `sudo` and `su` put the user into an incomplete and
> typically unexpected environment, as compared to using the "--login"
> options. One could say they turn you into "nobody", but with privileges.
>
> In general, I recommend to learn the difference between them and use
> them accordingly.
>
> On old-school distros, there is not usually a big problem, but on Guix
> it really matters, because we use the login shell initialization to
> export some environment variables, and the resulting environment is what
> provides the per-user view of installed packages. 
>
> So, if you don't login when elevating privileges, you get a weird
> environment and your view of Guix will be unexpected. As you noticed,
> the environment you got from `sudo su` lacked any user's packages or
> channels.

Thank you very much for the explanation!  I have just checked out the
manpages for sudo, su, and their corresponding --login options.

I knew that there was a difference between sudo and su, but I actually
thought su was doing what `sudo --login` does!  That doesn't seem true.

As you say, it has never really mattered for me, and I didn't feel any
difference even in 4 years of using NixOS.  I'm happy to learn that
I have to pay attention to those differences with Guix.

>> I think I did guix pull as root once at the beginning of the
>> installation of this machine 3 months ago.  I ran sudo guix pull
>> a couple of times, before I managed to remember that guix pull should be
>> run as normal user (I think?).
>
> `guix pull` should be run as any user that you use. So, if you ever use
> the root user, we highly recommend you update root's packages sometimes,
> too. If you never login as root, and do not run any programs as root,
> then it doesn't matter very much.

Nah, I don't ever login as root, so I stick to running `guix pull` as my
normal user.

I realize from what you are saying that users on a system may all have
different versions of Guix, and they will peacefully co-exist.  Not my
use case, but quite impressive!

>> The blurred parts of the output are due to the fact that Linux Libre
>> does not detect all my devices.
>> 
>> By the way, please tell me if there is anything inappropriate in my
>> message: I'm still not sure how to talk about certain things, as you can
>> see :-)
>
> No worries :) I don't think those other channels are relevant to your
> problem.

They were not indeed.

Thanks again!

-
Sergiu

original-error-message
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transient-error-1
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transient-error-2
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