Cryptography 2.6 crashes pip-compile

[NickG123]

Running pip-compile with cryptography 2.6 results in a crash from pip.

Works fine with cryptography 2.5.

Environment Versions

1. CentOS 7
2. Python version: 3.7.1
3. pip version: 19.0.1
4. pip-tools version: 3.4.0

Steps to replicate

1. Create a requirements.in containing cryptography==2.6
2. Run pip-compile requirements.in

Expected result

pip-compile should properly produce the requirements.txt

Actual result

Traceback (most recent call last):
  File "<virtualenv>/bin/pip-compile", line 10, in <module>
    sys.exit(cli())
  File "<virtualenv>/lib/python3.7/site-packages/click/core.py", line 764, in __call__
    return self.main(*args, **kwargs)
  File "<virtualenv>/lib/python3.7/site-packages/click/core.py", line 717, in main
    rv = self.invoke(ctx)
  File "<virtualenv>/lib/python3.7/site-packages/click/core.py", line 956, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "<virtualenv>/lib/python3.7/site-packages/click/core.py", line 555, in invoke
    return callback(*args, **kwargs)
  File "<virtualenv>/lib/python3.7/site-packages/piptools/scripts/compile.py", line 197, in cli
    results = resolver.resolve(max_rounds=max_rounds)
  File "<virtualenv>/lib/python3.7/site-packages/piptools/resolver.py", line 101, in resolve
    has_changed, best_matches = self._resolve_one_round()
  File "<virtualenv>/lib/python3.7/site-packages/piptools/resolver.py", line 198, in _resolve_one_round
    for dep in self._iter_dependencies(best_match):
  File "<virtualenv>/lib/python3.7/site-packages/piptools/resolver.py", line 284, in _iter_dependencies
    dependencies = self.repository.get_dependencies(ireq)
  File "<virtualenv>/lib/python3.7/site-packages/piptools/repositories/local.py", line 65, in get_dependencies
    return self.repository.get_dependencies(ireq)
  File "<virtualenv>/lib/python3.7/site-packages/piptools/repositories/pypi.py", line 225, in get_dependencies
    self._dependencies_cache[ireq] = self.resolve_reqs(download_dir, ireq, wheel_cache)
  File "<virtualenv>/lib/python3.7/site-packages/piptools/repositories/pypi.py", line 191, in resolve_reqs
    results = resolver._resolve_one(reqset, ireq)
  File "<virtualenv>/lib/python3.7/site-packages/pip/_internal/resolve.py", line 294, in _resolve_one
    abstract_dist = self._get_abstract_dist_for(req_to_install)
  File "<virtualenv>/lib/python3.7/site-packages/pip/_internal/resolve.py", line 242, in _get_abstract_dist_for
    self.require_hashes
  File "<virtualenv>/lib/python3.7/site-packages/pip/_internal/operations/prepare.py", line 349, in prepare_linked_requirement
    abstract_dist.prep_for_dist(finder, self.build_isolation)
  File "<virtualenv>/lib/python3.7/site-packages/pip/_internal/operations/prepare.py", line 158, in prep_for_dist
    self.req.prepare_metadata()
  File "<virtualenv>/lib/python3.7/site-packages/pip/_internal/req/req_install.py", line 534, in prepare_metadata
    self.prepare_pep517_metadata()
  File "<virtualenv>/lib/python3.7/site-packages/pip/_internal/req/req_install.py", line 579, in prepare_pep517_metadata
    metadata_dir
  File "<virtualenv>/lib/python3.7/site-packages/pip/_vendor/pep517/wrappers.py", line 86, in prepare_metadata_for_build_wheel
    'config_settings': config_settings,
  File "<virtualenv>/lib/python3.7/site-packages/pip/_vendor/pep517/wrappers.py", line 155, in _call_hook
    extra_environ={'PEP517_BUILD_BACKEND': build_backend}
  File "<virtualenv>/lib/python3.7/site-packages/pip/_internal/req/req_install.py", line 517, in runner
    spinner=spinner
  File "<virtualenv>/lib/python3.7/site-packages/pip/_internal/utils/misc.py", line 761, in call_subprocess
    % (command_desc, proc.returncode, cwd))
pip._internal.exceptions.InstallationError: Command "<virtualenv>/bin/python3.7 <virtualenv>/lib/python3.7/site-packages/pip/_vendor/pep517/_in_process.py prepare_metadata_for_build_wheel /tmp/tmp_gsmhfhu" failed with error code 1 in /tmp/tmp_kfjmnf1build/cryptography

[atugushev]

Hello @NickG123,

Thank you for the report! It's probably related to the #721 issue. I couldn't reproduce it locally, could you change build_isolation to True (it is False currently) in the <virtualenv>/lib/python3.7/site-packages/piptools/repositories/pypi.py file line 164 and try pip-compile again?

[NickG123]

Hi @atugushev, that does solve the issue.
Apologies for the duplicate issue, I will follow along #721.

[atugushev]

No worries! Thanks anyways for your contribution. I'll close this issue in favour of #721.