Re: [PATCH 2/2] gnu: libxml2: Build python bindings separately.

[Mark H Weaver <mhw@netris.org>]

宋文武 <iyzsong@gmail.com> writes:

> Mark H Weaver <mhw@netris.org> writes:
>
>> 宋文武 <iyzsong@gmail.com> writes:
>>
>>> * gnu/packages/xml.scm (libxml2)[native-inputs]: Remove python.
>>>   [arguments]: Remove.
>>>   (python-libxml2, python2-libxml): New variables.
>>> ---
>>>  gnu/packages/xml.scm | 53 ++++++++++++++++++++++++++++++----------------------
>>>  1 file changed, 31 insertions(+), 22 deletions(-)
>>>
>>> diff --git a/gnu/packages/xml.scm b/gnu/packages/xml.scm
>>> index a4c81b2..22d4e52 100644
>>> --- a/gnu/packages/xml.scm
>>> +++ b/gnu/packages/xml.scm
>>
>> [...]
>>
>>> +(define-public python2-libxml
>>> +  (package-with-python2 python-libxml2))
>>> +
>>
>> Due to non-obvious complications arising from the fact that xml.scm and
>> python.scm are mutually dependent on each other, we can't use
>> 'package-with-python2' from xml.scm.  For now, I suggest moving it to
>> python.scm, where all other uses of 'package-with-python2' are currently
>> located.
>>
>> For an explanation, see:
>>
>> https://lists.gnu.org/archive/html/guix-devel/2014-12/msg00355.html
> Thanks for explainging, but when I put it into python.scm,
> I got "Unbound variable: libxml2" when running:
>   $ ./pre-inst-env guix package -i python2-libxml
> or:
>   $ make
> but not:
>   $ ./pre-inst-env guix build python2-libxml
>
> Any ideas? Thanks!

It turns out that 'package-with-python2' is no longer exported from
(gnu packages python), but rather from (guix build-system python) which
is not part of any cycles, so it is now okay to use 'package-with-python2'
from other modules.

In fact, because of the (inherit libxml2) in 'python-libxml2', these
packages should be in xml.scm, right where you had put them -- or at
least not in any other module that shares a cycle with xml.scm -- so
please disregard my suggestion that they should be moved.

However, I just noticed one minor mispelling: the variable should be
named 'python2-libxml2', not 'python2-libxml'.

    Thanks!
      Mark