Re: What to do when udpating a package ?

[Edouard Klein]

Hi Julien,

Thank you for your answer.

Julien Lepiller writes:

> Le 15 mai 2020 03:20:06 GMT-04:00, Edouard Klein <address@hidden> a écrit :
>>Dear Guix Developers,
>>
>>I have a few beginner questions.
>>Attached to this email you will find the "reverse-package" graph of
>>python-prompt-toolkit.
>
> Hi,
>
> In general, some packages on master may fail to build. We try to fix these, 
> but it's not always easy.
>
> When updating a package, you should make sure that its dependents all
> build or did not build before your changes. Fix those who now fail to
> build.

OK, got it. I'll avoid touching those that fail to build on the build farm.

>
> I don't think having both versions is a good thing because it will create 
> conflicts when installing (have you tried to install a package that 
> propagates both to a profile?). It would be ok if they had no file in common 
> but I doubt it is the case. For any package that requires version 2, make 
> sure its dependencies only use version 2, or update the package if the newer 
> version can support version 3. It's not always easy to find the right order 
> of upgrades, as you should make sure nothing is broken in between patches.
>
I did not try to install them, and you were correct, here is what I get
when I try to install python-iml:

guix install: error: profile contains conflicting entries for 
python-prompt-toolkit
guix install: error:   first entry: python-prompt-toolkit@3.0.5 
/gnu/store/80lzvbzvfp4226ic7czhch4p0mlsdwlv-python-prompt-toolkit-3.0.5
guix install: error:    ... propagated from python-ipython@7.9.0
guix install: error:    ... propagated from python-iml@0.6.2
guix install: error:   second entry: python-prompt-toolkit@2.0.7 
/gnu/store/0k7a0yp3b2sqqj8jhl7vp3cabb0x2mwd-python-prompt-toolkit-2.0.7
guix install: error:    ... propagated from python-iml@0.6.2
hint: You cannot have two different versions or variants of `python-iml' in the 
same profile.

The problem is that python-iml depends on both python-ipython (which
accepts python-prompt-toolkit 3) and python-prompt-toolkit-2. Looking at
the github repo, the last update was in 2018, I don't think we'll see an
update soon.

I could pin python-ipython to python-prompt-toolkit-2, but that would
just delay the problem and put it on somebody else's lap to let
python-ipython move to python-prompt-toolkit 3.

As I was typing a question I ctrl-Fed for 'variants' in the doc and
ended up learning about package-input-rewriting. I will try to make
python-iml depend on python-ipython, but with the prompt-toolkit input
replaced with its version 2 on the fly. I think it makes sense. Is it the 
correct
way to do what needs to be done ?

> Relying on propagated inputs to provide a dependency is going to
> simplify the graphs, but not the work of other maintainers who will
> have to investigate how the dependency is provided, so I don't think
> it's a good idea.

I understood your sentence as saying that relying on propagated inputs
of propagated inputs is not a good idea and that dependencies are better
explicitly stated in the guix package. Is that correct ?


>
> You should rebuild every dependent, even those who only depend on the
> package for native-inputs, since there can be an error an any point
> (though less likely).

OK, I'll try that next when I'll have gotten python-iml to build.

>
> I hope I answered your questions. Your message was split into two
> multipart sections and my client wasn't able to cite the interesting
> part, which makes it hard for me to check what your questions were
> while typing my answer.

You have indeed answered a lot of them, thank you very much :) Sorry
about the multipart stuff, I don't know how to configure my client
(mu4e) not to do that. I'll look into it.

Cheers,

Edouard.