Re: gnu: python-pytest: Update to 5.2.1.

[Maxim Cournoyer]

Hello,

Marius Bakke <address@hidden> writes:

> Tanguy Le Carrour <address@hidden> writes:
>
>> Hi Guix!
>>
>> I'm working on updating python-pytest and… not everything is going as
>> smoothly as I was expecting! :-(
>>
>> Pytest 5.2.1 depends on Pluggy >=0.12.0… which depends on
>> importlib-metadata. But when I had the latter as a propagated-input to
>> python-pluggy, then `guix build` gets stuck.
>>
>>     diff --git a/gnu/packages/python-xyz.scm b/gnu/packages/python-xyz.scm
>>     index a7f83dcd31..ab80cdebf9 100644
>>     --- a/gnu/packages/python-xyz.scm
>>     +++ b/gnu/packages/python-xyz.scm
>>     @@ -8914,17 +8914,19 @@ library as well as on the command line.")
>>      (define-public python-pluggy
>>        (package
>>         (name "python-pluggy")
>>     -   (version "0.11.0")
>>     +   (version "0.13.0")
>>         (source
>>          (origin
>>           (method url-fetch)
>>           (uri (pypi-uri "pluggy" version))
>>           (sha256
>>            (base32
>>     -       "10511a54dvafw1jrk75mrhml53c7b7w4yaw7241696lc2hfvr895"))))
>>     +       "0d4gsvb4kjqhiqqi4bbsdp7s1xlyl5phibcw1q1mrpd65xia2pzs"))))
>>         (build-system python-build-system)
>>         (native-inputs
>>          `(("python-setuptools-scm" ,python-setuptools-scm)))
>>     +   (propagated-inputs
>>     +    `(("python-importlib-metadata" ,python-importlib-metadata)))
>>         (synopsis "Plugin and hook calling mechanism for Python")
>>         (description "Pluggy is an extraction of the plugin manager as used 
>> by
>>      Pytest but stripped of Pytest specific details.")
>>
>> The problem seems to be that python-importlib-metadata's dependency graph
>> contains… python-pluggy!
>>
>> How am I supposed to fix this chicken and egg situation?! Is this
>> something that should be notified to upstream?!
>
> It would be great if you can make upstream aware of the issue.
>
> Note that if you just want to be able to use Pytest 5.x on the master
> branch, you can instead add a separate 'python-pluggy-0.13' variable and
> use that for 'python-pytest-5'.
>
> We'll still need to break the cycle in 'core-updates' though...

I too had looked into updating python-pytest, and realized the same
thing.  There's a way out, though.  Python 3.8.0 will include
'import-metadata' as a core library [0].

Let's package Python 3.8.0 on core-updates!

[0]  https://docs.python.org/3/whatsnew/3.8.html#new-modules

Maxim