The package you're referring to have only support of python2 interpreters
(python2_7 (CPython) and pypy (not the pypy3)).
It seems, by default (if neither of PYTHON_SINGLE_TARGET is set), portage
tries to do the "magic" (well, in my opinion, it opposes to the Gentoo
Philosophy, and it should throw the same error even with "defaults") and
automatically chooses the 2_7 single target for it.
But when you explicitly specify the targets in make.conf, it obeys and don't
do that magic anymore, so condition of "exactly one of supported
single_targets (pypy, pyhton2.7)" is not meeting anymore".
That's why you getting the error.
В письме от суббота, 7 июля 2018 г. 21:31:48 MSK пользователь Andreas Fink
написал:
> Hello,
> I have a question considering PYTHON_SINGLE_TARGET because it seems to
> behave inconsistently on my system and I cannot find any documentation
> about it, that would guide me in the right direction how to fix it.
> Running emerge --info I see the following (I'm on ~amd64):
> ... PYTHON_SINGLE_TARGET="python3_5" PYTHON_TARGETS="python2_7 python3_5"
> ...
>
> This output is the default for ~amd64, neither PYTHON_SINGLE_TARGET nor
> PYTHON_TARGETS has been set explicitly.
> If I do an emerge -av asciidoc, I see the following output:
> ebuild R ] app-text/asciidoc-8.6.10::gentoo USE="-examples -graphviz
> -highlight {-test}" PYTHON_SINGLE_TARGET="python2_7 -pypy"
> PYTHON_TARGETS="python2_7 -pypy"
>
> Setting PYTHON_SINGLE_TARGET and PYTHON_TARGETS in /etc/portage/make.conf
> explicitly to: PYTHON_SINGLE_TARGET="python3_5"
> PYTHON_TARGETS="python2_7 python3_5"
>
> Now emerge --info doesn't show any difference. It's still the same output.
> Doing an emerge -av asciidoc I get now this output:
> !!! The ebuild selected to satisfy "asciidoc" has unmet requirements.
> - app-text/asciidoc-8.6.10::gentoo USE="-examples -graphviz -highlight
> -test" ABI_X86="(64)" PYTHON_SINGLE_TARGET="-pypy -python2_7"
> PYTHON_TARGETS="python2_7 -pypy"
>
> The following REQUIRED_USE flag constraints are unsatisfied:
> exactly-one-of ( python_single_target_pypy
> python_single_target_python2_7 )
>
>
> This seems for me to be really inconsistent, considering the fact that we
> usually request users to provide an emerge --info, which wouldn't show any
> difference.
> Why am I able to merge in the first case the package, but in the second case
> I get an error? I really cannot understand where the
> python_single_target_python2_7 is set in the first case.
> Anyone who has more insight into that case?
>
> Cheers
> Andreas
