'guix environment' as a build tool. (was: [GSoC] Continuous integration tool à la Hydra.)

[Mathieu Lirzin <mthl@gnu.org>]

ludo@gnu.org (Ludovic Courtès) writes:

> Mathieu Lirzin <mthl@gnu.org> skribis:
>
>> I have tested successfully with the following command on a foreign
>> system:
>>
>>   guix environment --ad-hoc automake pkg-config guile guix libgcrypt sqlite guile-sqlite3
>>
>> Tell me if it works for you.
>>
>>> How about including a guix package definition then we can easily build
>>> it assuming "we" know how to do out-of-guix-tree package building :)
>>
>> It would indeed be nice to provide an easy way for Guix users to install
>> Cuirass.  IMHO package definitions meant as a development build tool is
>> confusing and should be avoided.  Nonetheless, I think it is useful to
>> document the previous 'guix environment ...' command in the README.
>
> What about providing a ‘guix.scm’ file that people could pass to ‘guix
> environment -l’ (instead of typing the long command above), and to ‘guix
> package -f’ (info "(guix) Invoking guix package")?

'guix environment -l' uses a package definition.  To me this abstraction
doesn't fit well in a development context:

 - the origin hash doesn't make sense.
 - packages already included in Guix have redundant description and synopsis.
 - package definitions rely on Guix internals.

In fact what 'guix.scm' contains feels more like a "debian" directory or
a "PACKAGE.spec" file on steroid because of the "guix environment -l"
feature which derives from it but doesn't appear as first class.

An idea that I like better and is less invasive, would be to complement
bootstrap scripts with:

  ./bootstrap --with-guix

This command would:

- generate a guix-env script that wraps 'guix environment ...' if it
  doesn't exist.
- Invoke ./guix-env
- Invoke autoreconf -vfi

if the user wants to enter this environment Later it will have to invoke
'./guix-env'.

Some interesting things could be done beyond this, for example by using
per repository profiles that would save development environments.  This
would allow developpers to easily use different setups.

WDYT?

-- 
Mathieu Lirzin