frosted FTBFS ImportError: No module named builtins

[Hans Joachim Desserud]

frosted currently fails to build on Wily Werewolf with the following error message:
============================= test session starts ==============================
platform linux2 -- Python 2.7.10 -- py-1.4.29 -- pytest-2.7.0
rootdir: /«PKGBUILDDIR», inifile:
collected 0 items / 9 errors

==================================== ERRORS ====================================
__________________ ERROR collecting frosted/test/test_api.py ___________________
frosted/test/test_api.py:30: in <module>
    from frosted.api import check_path, check_recursive
frosted/api.py:30: in <module>
    from frosted import checker, settings
frosted/checker.py:22: in <module>
    import builtins
E ImportError: No module named builtins
________________ ERROR collecting frosted/test/test_doctests.py ________________
frosted/test/test_doctests.py:10: in <module>
    from .utils import flakes
frosted/test/utils.py:8: in <module>
    from frosted import checker
frosted/checker.py:22: in <module>
    import builtins
E ImportError: No module named builtins
_____________ ERROR collecting frosted/test/test_function_calls.py _____________
frosted/test/test_function_calls.py:12: in <module>
    from .utils import flakes
frosted/test/utils.py:8: in <module>
    from frosted import checker
frosted/checker.py:22: in <module>
    import builtins
E ImportError: No module named builtins
________________ ERROR collecting frosted/test/test_imports.py _________________
frosted/test/test_imports.py:11: in <module>
    from .utils import flakes
frosted/test/utils.py:8: in <module>
    from frosted import checker
frosted/checker.py:22: in <module>
    import builtins
E ImportError: No module named builtins
__________________ ERROR collecting frosted/test/test_noqa.py __________________
frosted/test/test_noqa.py:2: in <module>
    from frosted.api import _noqa_lines, _re_noqa, check
frosted/api.py:30: in <module>
    from frosted import checker, settings
frosted/checker.py:22: in <module>
    import builtins
E ImportError: No module named builtins
_________________ ERROR collecting frosted/test/test_other.py __________________
frosted/test/test_other.py:12: in <module>
    from .utils import flakes
frosted/test/utils.py:8: in <module>
    from frosted import checker
frosted/checker.py:22: in <module>
    import builtins
E ImportError: No module named builtins
_ ERROR collecting frosted/test/test_return_with_arguments_inside_generator.py _
frosted/test/test_return_with_arguments_inside_generator.py:10: in <module>
    from .utils import flakes
frosted/test/utils.py:8: in <module>
    from frosted import checker
frosted/checker.py:22: in <module>
    import builtins
E ImportError: No module named builtins
_________________ ERROR collecting frosted/test/test_script.py _________________
frosted/test/test_script.py:33: in <module>
    from frosted.api import iter_source_code
frosted/api.py:30: in <module>
    from frosted import checker, settings
frosted/checker.py:22: in <module>
    import builtins
E ImportError: No module named builtins
____________ ERROR collecting frosted/test/test_undefined_names.py _____________
frosted/test/test_undefined_names.py:10: in <module>
    from frosted import checker
frosted/checker.py:22: in <module>
    import builtins
E ImportError: No module named builtins
=========================== 9 error in 0.26 seconds ============================
E: pybuild pybuild:256: test: plugin distutils failed with: exit code=1: python2.7 setup.py test
dh_auto_test: pybuild --test -i python{version} -p 2.7 --dir . returned exit code 13
make: *** [build] Error 13
debian/rules:6: recipe for target 'build' failed
dpkg-buildpackage: error: debian/rules build gave error exit status 2

I've investigated this a bit and found the following:
Firstly, I'm able to reproduce the issue on my Wily vm.
I am unable to reproduce it on a Debian Sid vm, so it looks like an Ubuntu-only issue.
When running python on Sid, I was able to import "builtins", but it failed on Ubuntu.
I found that the builtins module imported on Sid resided in `/usr/lib/python2.7/dist-packages/builtins.py` which is owned by the package python-pies2overrides [1]. This is part of the python-pies source package [2].
I notice that this source package has an Ubuntu-delta, but it don't quite see how that would affect this issue.
Though I did see something interesting. In Debian, the python-pies binary depends on python-pies2overrides [3], while on Ubuntu it does not [4].
So Debian will pull it in as a dependency when building, but on Ubuntu it will be missing resulting in the error above.
I am not sure what has caused this difference though.

[1] https://packages.debian.org/sid/all/python-pies2overrides
[2] https://tracker.debian.org/pkg/python-pies
[3] https://packages.debian.org/unstable/python-pies
[4] http://packages.ubuntu.com/wily/python-pies

[Hans Joachim Desserud (hjd)]

Looks like this was removed alongside python-pies. It is currently not in any supported releases of Ubuntu or Debian, so closing.