Re: rolling back only a single package

["Catriel Omar D'Elía" <cdelia@dc.uba.ar>]

swedebugia <swedebugia@riseup.net> writes:

> On 2018-12-28 23:15, cdelia@dc.uba.ar wrote:
>> Hi
>>
>> On 2018-12-28 08:32, swedebugia wrote:
>>> "cdelia@dc.uba.ar" <cdelia@dc.uba.ar> skrev: (27 december 2018
>>> 20:52:23 CET)
>>>
>>>> Hi,
>>>>
>>>> I upgraded guix a couple of days ago, installed some things and now
>>>> I
>>>> found that xmobar just keeps segfaulting.
>>>>
>>>> Switching to specific generation it's really cool, but in this case
>>>> would "uninstall" all the software that it's between the
>>>> update-generation and the current one.
>>>>
>>>> So, there is any way to just downgrade a single package (resolving
>>>> it
>>>> dependencies) with out doing a full switch?
>>>>
>>>> I guess this it's connected to
>>>> https://lists.gnu.org/archive/html/help-guix/2016-08/msg00028.html
>>>>
>>>> And I could also switch and then manually re install. But maybe
>>>> there is
>>>> a standard or automatic way to do it.
>>>>
>>>> Thanks!
>>>
>>> Hi.
>>> I highly recommend you to use the declarative way of installing
>>> packages instead. See the manual.
>>>
>>
>> I'm intending to, but before that I rather install when need it, when
>> some pseudo complete usable system arise I'll write a declaration.
>>
>> Declarative it's great, but you have to get in your head all the things
>> that you'll need, before even beginning ...
>
> Really?
>
> I just add to the manifest every time I stumble over a missing part.
>
> I test out stuff with the imperative install and add it to the
> manifest once I'm sure I need it.
>

That seems to be a good approach.

Anyway I was talking about installing things that can be found.

> You can see my manifest here:
> https://gitlab.com/swedebugia/guix-config/blob/master/sdb.scm
>
>>
>>> You can use the former xmobar directly from the store if you have it
>>> or you could create an own package/channel that specifies the version
>>> you want.
>>>
>>
>> Well... I never GC nor delete generations. So it should be possible.
>> But I believe that's a temporal work around that should not be used.
>>
>> If I don't delete the generation that holds the earlier working version,
>> I could do that,
>>    but then I'll need to use the full path in the store or a symblink
>> manually created.
>>
>> I think that kind of stuff it's a tiny, but accumulative step towards
>> chaos. And I'm using git to scape from it XD
>>
>>> The best thing though is to report a bug and help by providing
>>> information e.g. by stracing it. Guide evolves quickly...
>>
>> It's xmonad, a haskell app. I'm not to proficient in haskell yet to help
>> with that.
>>
>> If I've time I'll report the bug, at least.
>
> Sounds good to me. :)
>
> Noone have reported anything about xmobar yet, it seems:
> https://debbugs.gnu.org/cgi/pkgreport.cgi?include=subject%3Axmobar;package=guix
>
> so you might be the first to find the bug.
>

I'm begging to think that it's a problem with GHC. There is a comment on
xmobar repo by version 28 that says that should be using 8.x something
GHC.
Besides, doesn't make sense to segfault with haskell code.

I'll check other answers first and then see if I can help.

>>
>>> --
>>> Sent from my p≡p for Android.