# Buggy code
def filter(cls, pythons):
    """
    Given a map of python interpreters in the format provided by PythonInterpreter.find(),
    filter out duplicate versions and versions we would prefer not to use.

    Returns a map in the same format as find.
    """
    good = []

    MAJOR, MINOR, SUBMINOR = range(3)

    def version_filter(version):
        return (
            version[MAJOR] == 2
            and version[MINOR] >= 6
            or version[MAJOR] == 3
            and version[MINOR] >= 2
        )

    all_versions = set(interpreter.identity.version for interpreter in pythons)
    good_versions = filter(version_filter, all_versions)

    for version in good_versions:
        # For each candidate, use the latest version we find on the filesystem.
        candidates = defaultdict(list)
        for interp in pythons:
            if interp.identity.version == version:
                candidates[interp.identity.interpreter].append(interp)
        for interp_class in candidates:
            candidates[interp_class].sort(
                key=lambda interp: os.path.getmtime(interp.binary), reverse=True
            )
            good.append(candidates[interp_class].pop(0))

    return good


# Traceback (KeyError)
$ pex -vvvvvvvvv cryptography==2.5
pex: Warning, using a UrllibContext which is known to be flaky.
pex: Please build pex with the requests module for more reliable downloads.
pex: Constructed UrllibContext context <pex.http.UrllibContext object at 0x7f2fe54f2fd0>
pex:
Modifying given platform of 'current':
Using the current platform of Platform(platform='linux_x86_64', impl='cp', version='37', abi='cp37m')
Under current interpreter PythonInterpreter('/usr/bin/python3.7', PythonIdentity('cp', 'cp37m', '37', 3, 7, 2), {})

To match given interpreter PythonInterpreter('/usr/bin/python3.7', PythonIdentity('cp', 'cp37m', '37', 3, 7, 2), {}).

Calculated platform: Platform(platform='linux_x86_64', impl='cp', version='37', abi='cp37m')
pex: R: tags for Platform(platform='linux_x86_64', impl='cp', version='37', abi='cp37m') x PythonInterpreter('/usr/bin/python3.7', PythonIdentity('cp', 'cp37m', '37', 3, 7, 2), {}) -> [('cp37', 'cp37m', 'manylinux1_x86_64'), ('cp37', 'cp37m', 'linux_x86_64'), ('cp37', 'abi3', 'manylinux1_x86_64'), ('cp37', 'abi3', 'linux_x86_64'), ('cp37', 'none', 'manylinux1_x86_64'), ('cp37', 'none', 'linux_x86_64'), ('py3', 'none', 'manylinux1_x86_64'), ('py3', 'none', 'linux_x86_64'), ('cp37', 'none', 'any'), ('cp3', 'none', 'any'), ('py37', 'none', 'any'), ('py3', 'none', 'any')]
pex: Warning, using a UrllibContext which is known to be flaky.
pex: Please build pex with the requests module for more reliable downloads.
pex: Constructed UrllibContext context <pex.http.UrllibContext object at 0x7f2fe5497ac8>
pex: crawling link i=0 link=Link('file:///home/jsirois/.pex/build') follow_links=False
pex: crawling link i=0 link=Link('https://pypi.org/simple/cryptography/') follow_links=False
**** Failed to install cryptography-2.5 (caused by: NonZeroExit("received exit code 1 during execution of `['/usr/bin/python3.7', '-sE', '-', 'bdist_wheel', '--dist-dir=/tmp/tmpbq0630tn']` while trying to execute `['/usr/bin/python3.7', '-sE', '-', 'bdist_wheel', '--dist-dir=/tmp/tmpbq0630tn']`")
):
stdout:

stderr:
Traceback (most recent call last):
File "/tmp/tmp9djbzpty/pex/vendor/_vendored/setuptools/setuptools/sandbox.py", line 154, in save_modules
yield saved
File "/tmp/tmp9djbzpty/pex/vendor/_vendored/setuptools/setuptools/sandbox.py", line 195, in setup_context
yield
File "/tmp/tmp9djbzpty/pex/vendor/_vendored/setuptools/setuptools/sandbox.py", line 250, in run_setup
_execfile(setup_script, ns)
File "/tmp/tmp9djbzpty/pex/vendor/_vendored/setuptools/setuptools/sandbox.py", line 45, in _execfile
exec(code, globals, locals)
File "/tmp/easy_install-j1m6g1u8/pycparser-2.19/setup.py", line 65, in <module>
# If there's no vectors locally that probably means we are in a tarball and
File "/tmp/tmp9djbzpty/pex/vendor/_vendored/setuptools/setuptools/__init__.py", line 142, in setup
_install_setup_requires(attrs)
File "/tmp/tmp9djbzpty/pex/vendor/_vendored/setuptools/setuptools/__init__.py", line 135, in _install_setup_requires
dist.parse_config_files(ignore_option_errors=True)
File "/tmp/tmp9djbzpty/pex/vendor/_vendored/setuptools/setuptools/dist.py", line 564, in parse_config_files
_Distribution.parse_config_files(self, filenames=filenames)
File "/usr/lib/python3.7/distutils/dist.py", line 397, in parse_config_files
filenames = self.find_config_files()
File "/usr/lib/python3.7/distutils/dist.py", line 352, in find_config_files
sys_dir = os.path.dirname(sys.modules['distutils'].__file__)
KeyError: 'distutils'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "<stdin>", line 14, in <module>
File "<string>", line 324, in <module>
File "/tmp/tmp9djbzpty/pex/vendor/_vendored/setuptools/setuptools/__init__.py", line 142, in setup
_install_setup_requires(attrs)
File "/tmp/tmp9djbzpty/pex/vendor/_vendored/setuptools/setuptools/__init__.py", line 137, in _install_setup_requires
dist.fetch_build_eggs(dist.setup_requires)
File "/tmp/tmp9djbzpty/pex/vendor/_vendored/setuptools/setuptools/dist.py", line 586, in fetch_build_eggs
replace_conflicting=True,
File "/tmp/tmp9djbzpty/pex/vendor/_vendored/setuptools/pkg_resources/__init__.py", line 780, in resolve
replace_conflicting=replace_conflicting
File "/tmp/tmp9djbzpty/pex/vendor/_vendored/setuptools/pkg_resources/__init__.py", line 1063, in best_match
return self.obtain(req, installer)
File "/tmp/tmp9djbzpty/pex/vendor/_vendored/setuptools/pkg_resources/__init__.py", line 1075, in obtain
return installer(requirement)
File "/tmp/tmp9djbzpty/pex/vendor/_vendored/setuptools/setuptools/dist.py", line 653, in fetch_build_egg
return cmd.easy_install(req)
File "/tmp/tmp9djbzpty/pex/vendor/_vendored/setuptools/setuptools/command/easy_install.py", line 679, in easy_install
return self.install_item(spec, dist.location, tmpdir, deps)
File "/tmp/tmp9djbzpty/pex/vendor/_vendored/setuptools/setuptools/command/easy_install.py", line 705, in install_item
dists = self.install_eggs(spec, download, tmpdir)
File "/tmp/tmp9djbzpty/pex/vendor/_vendored/setuptools/setuptools/command/easy_install.py", line 890, in install_eggs
return self.build_and_install(setup_script, setup_base)
File "/tmp/tmp9djbzpty/pex/vendor/_vendored/setuptools/setuptools/command/easy_install.py", line 1158, in build_and_install
self.run_setup(setup_script, setup_base, args)
File "/tmp/tmp9djbzpty/pex/vendor/_vendored/setuptools/setuptools/command/easy_install.py", line 1144, in run_setup
run_setup(setup_script, args)
File "/tmp/tmp9djbzpty/pex/vendor/_vendored/setuptools/setuptools/sandbox.py", line 253, in run_setup
raise
File "/usr/lib/python3.7/contextlib.py", line 130, in __exit__
self.gen.throw(type, value, traceback)
File "/tmp/tmp9djbzpty/pex/vendor/_vendored/setuptools/setuptools/sandbox.py", line 195, in setup_context
yield
File "/usr/lib/python3.7/contextlib.py", line 130, in __exit__
self.gen.throw(type, value, traceback)
File "/tmp/tmp9djbzpty/pex/vendor/_vendored/setuptools/setuptools/sandbox.py", line 166, in save_modules
saved_exc.resume()
File "/tmp/tmp9djbzpty/pex/vendor/_vendored/setuptools/setuptools/sandbox.py", line 141, in resume
six.reraise(type, exc, self._tb)
File "/tmp/tmp9djbzpty/pex/vendor/_vendored/setuptools/setuptools/_vendor/six.py", line 685, in reraise
raise value.with_traceback(tb)
File "/tmp/tmp9djbzpty/pex/vendor/_vendored/setuptools/setuptools/sandbox.py", line 154, in save_modules
yield saved
File "/tmp/tmp9djbzpty/pex/vendor/_vendored/setuptools/setuptools/sandbox.py", line 195, in setup_context
yield
File "/tmp/tmp9djbzpty/pex/vendor/_vendored/setuptools/setuptools/sandbox.py", line 250, in run_setup
_execfile(setup_script, ns)
File "/tmp/tmp9djbzpty/pex/vendor/_vendored/setuptools/setuptools/sandbox.py", line 45, in _execfile
exec(code, globals, locals)
File "/tmp/easy_install-j1m6g1u8/pycparser-2.19/setup.py", line 65, in <module>
# If there's no vectors locally that probably means we are in a tarball and
File "/tmp/tmp9djbzpty/pex/vendor/_vendored/setuptools/setuptools/__init__.py", line 142, in setup
_install_setup_requires(attrs)
File "/tmp/tmp9djbzpty/pex/vendor/_vendored/setuptools/setuptools/__init__.py", line 135, in _install_setup_requires
dist.parse_config_files(ignore_option_errors=True)
File "/tmp/tmp9djbzpty/pex/vendor/_vendored/setuptools/setuptools/dist.py", line 564, in parse_config_files
_Distribution.parse_config_files(self, filenames=filenames)
File "/usr/lib/python3.7/distutils/dist.py", line 397, in parse_config_files
filenames = self.find_config_files()
File "/usr/lib/python3.7/distutils/dist.py", line 352, in find_config_files
sys_dir = os.path.dirname(sys.modules['distutils'].__file__)
KeyError: 'distutils'


pex: Failed to install package at /tmp/tmppt__qt4e/cryptography-2.5: Failed to install /tmp/tmppt__qt4e/cryptography-2.5
Traceback (most recent call last):
File "/home/jsirois/.venv/pex/bin/pex", line 10, in <module>
sys.exit(main())
File "/home/jsirois/.venv/pex/lib/python3.7/site-packages/pex/bin/pex.py", line 662, in main
pex_builder = build_pex(reqs, options, resolver_options_builder)
File "/home/jsirois/.venv/pex/lib/python3.7/site-packages/pex/bin/pex.py", line 592, in build_pex
for resolved_dist in resolveds:
File "/home/jsirois/.venv/pex/lib/python3.7/site-packages/pex/resolver.py", line 565, in resolve_multi
use_manylinux=use_manylinux):
File "/home/jsirois/.venv/pex/lib/python3.7/site-packages/pex/resolver.py", line 501, in resolve
return resolver.resolve(resolvables_from_iterable(requirements, builder, interpreter=interpreter))
File "/home/jsirois/.venv/pex/lib/python3.7/site-packages/pex/resolver.py", line 299, in resolve
dist = self.build(package, resolvable.options)
File "/home/jsirois/.venv/pex/lib/python3.7/site-packages/pex/resolver.py", line 378, in build
dist = super(CachingResolver, self).build(package, options)
File "/home/jsirois/.venv/pex/lib/python3.7/site-packages/pex/resolver.py", line 257, in build
raise Untranslateable('Package %s is not translateable by %s' % (package, translator))
pex.resolver.Untranslateable: Package SourcePackage('file:///home/jsirois/.pex/build/cryptography-2.5.tar.gz') is not translateable by ChainedTranslator(WheelTranslator, EggTranslator, SourceTranslator)

# Fixed code
def filter(cls, pythons):
    """
    Given a map of python interpreters in the format provided by PythonInterpreter.find(),
    filter out duplicate versions and versions we would prefer not to use.

    Returns a map in the same format as find.
    """
    good = []

    MAJOR, MINOR, SUBMINOR = range(3)

    def version_filter(version):
        return (
            version[MAJOR] == 2
            and version[MINOR] >= 7
            or version[MAJOR] == 3
            and version[MINOR] >= 4
        )

    all_versions = set(interpreter.identity.version for interpreter in pythons)
    good_versions = filter(version_filter, all_versions)

    for version in good_versions:
        # For each candidate, use the latest version we find on the filesystem.
        candidates = defaultdict(list)
        for interp in pythons:
            if interp.identity.version == version:
                candidates[interp.identity.interpreter].append(interp)
        for interp_class in candidates:
            candidates[interp_class].sort(
                key=lambda interp: os.path.getmtime(interp.binary), reverse=True
            )
            good.append(candidates[interp_class].pop(0))

    return good