add2virtualenv logic breaks builds of packages with modern build backend #98
Description
The logic in add2virtualenv of adding paths to the front of sys.path breaks installing packages in the virtualenv that use a PEP517 build. In preparing the build environment pip tries to determine the necessary sys.path using a "sitecustomize.py" written in pip's _internal/build_env.py, which gets confused with paths not being added to the end of sys.path. The result is that the lib-dynload path of the Python environment gets removed from sys.path and pip install fails with a traceback like this
# pip install .
Processing /Devel/foo
Installing build dependencies ... done
Getting requirements to build wheel ... done
ERROR: Exception:
Traceback (most recent call last):
File "/root/.virtualenvs/foo/lib/python3.11/site-packages/pip/_internal/cli/base_command.py", line 180, in exc_logging_wrapper
status = run_func(*args)
^^^^^^^^^^^^^^^
File "/root/.virtualenvs/foo/lib/python3.11/site-packages/pip/_internal/cli/req_command.py", line 245, in wrapper
return func(self, options, args)
^^^^^^^^^^^^^^^^^^^^^^^^^
File "/root/.virtualenvs/foo/lib/python3.11/site-packages/pip/_internal/commands/install.py", line 377, in run
requirement_set = resolver.resolve(
^^^^^^^^^^^^^^^^^
File "/root/.virtualenvs/foo/lib/python3.11/site-packages/pip/_internal/resolution/resolvelib/resolver.py", line 76, in resolve
collected = self.factory.collect_root_requirements(root_reqs)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/root/.virtualenvs/foo/lib/python3.11/site-packages/pip/_internal/resolution/resolvelib/factory.py", line 534, in collect_root_requirements
reqs = list(
^^^^^
File "/root/.virtualenvs/foo/lib/python3.11/site-packages/pip/_internal/resolution/resolvelib/factory.py", line 490, in _make_requirements_from_install_req
cand = self._make_base_candidate_from_link(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/root/.virtualenvs/foo/lib/python3.11/site-packages/pip/_internal/resolution/resolvelib/factory.py", line 228, in _make_base_candidate_from_link
self._link_candidate_cache[link] = LinkCandidate(
^^^^^^^^^^^^^^
File "/root/.virtualenvs/foo/lib/python3.11/site-packages/pip/_internal/resolution/resolvelib/candidates.py", line 290, in __init__
super().__init__(
File "/root/.virtualenvs/foo/lib/python3.11/site-packages/pip/_internal/resolution/resolvelib/candidates.py", line 156, in __init__
self.dist = self._prepare()
^^^^^^^^^^^^^^^
File "/root/.virtualenvs/foo/lib/python3.11/site-packages/pip/_internal/resolution/resolvelib/candidates.py", line 222, in _prepare
dist = self._prepare_distribution()
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/root/.virtualenvs/foo/lib/python3.11/site-packages/pip/_internal/resolution/resolvelib/candidates.py", line 301, in _prepare_distribution
return preparer.prepare_linked_requirement(self._ireq, parallel_builds=True)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/root/.virtualenvs/foo/lib/python3.11/site-packages/pip/_internal/operations/prepare.py", line 525, in prepare_linked_requirement
return self._prepare_linked_requirement(req, parallel_builds)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/root/.virtualenvs/foo/lib/python3.11/site-packages/pip/_internal/operations/prepare.py", line 640, in _prepare_linked_requirement
dist = _get_prepared_distribution(
^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/root/.virtualenvs/foo/lib/python3.11/site-packages/pip/_internal/operations/prepare.py", line 71, in _get_prepared_distribution
abstract_dist.prepare_distribution_metadata(
File "/root/.virtualenvs/foo/lib/python3.11/site-packages/pip/_internal/distributions/sdist.py", line 54, in prepare_distribution_metadata
self._install_build_reqs(finder)
File "/root/.virtualenvs/foo/lib/python3.11/site-packages/pip/_internal/distributions/sdist.py", line 124, in _install_build_reqs
build_reqs = self._get_build_requires_wheel()
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/root/.virtualenvs/foo/lib/python3.11/site-packages/pip/_internal/distributions/sdist.py", line 101, in _get_build_requires_wheel
return backend.get_requires_for_build_wheel()
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/root/.virtualenvs/foo/lib/python3.11/site-packages/pip/_internal/utils/misc.py", line 745, in get_requires_for_build_wheel
return super().get_requires_for_build_wheel(config_settings=cs)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/root/.virtualenvs/foo/lib/python3.11/site-packages/pip/_vendor/pyproject_hooks/_impl.py", line 166, in get_requires_for_build_wheel
return self._call_hook('get_requires_for_build_wheel', {
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/root/.virtualenvs/foo/lib/python3.11/site-packages/pip/_vendor/pyproject_hooks/_impl.py", line 321, in _call_hook
raise BackendUnavailable(data.get('traceback', ''))
pip._vendor.pyproject_hooks._impl.BackendUnavailable: Traceback (most recent call last):
File "/root/.virtualenvs/foo/lib/python3.11/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 77, in _build_backend
obj = import_module(mod_path)
^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/lib64/python3.11/importlib/__init__.py", line 126, in import_module
return _bootstrap._gcd_import(name[level:], package, level)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "<frozen importlib._bootstrap>", line 1204, in _gcd_import
File "<frozen importlib._bootstrap>", line 1176, in _find_and_load
File "<frozen importlib._bootstrap>", line 1126, in _find_and_load_unlocked
File "<frozen importlib._bootstrap>", line 241, in _call_with_frames_removed
File "<frozen importlib._bootstrap>", line 1204, in _gcd_import
File "<frozen importlib._bootstrap>", line 1176, in _find_and_load
File "<frozen importlib._bootstrap>", line 1147, in _find_and_load_unlocked
File "<frozen importlib._bootstrap>", line 690, in _load_unlocked
File "<frozen importlib._bootstrap_external>", line 940, in exec_module
File "<frozen importlib._bootstrap>", line 241, in _call_with_frames_removed
File "/tmp/pip-build-env-pitma8s7/overlay/lib/python3.11/site-packages/setuptools/__init__.py", line 8, in <module>
import _distutils_hack.override # noqa: F401
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/root/.virtualenvs/foo/lib/python3.11/site-packages/_distutils_hack/override.py", line 1, in <module>
__import__('_distutils_hack').do_override()
File "/root/.virtualenvs/foo/lib/python3.11/site-packages/_distutils_hack/__init__.py", line 70, in do_override
ensure_local_distutils()
File "/root/.virtualenvs/foo/lib/python3.11/site-packages/_distutils_hack/__init__.py", line 53, in ensure_local_distutils
importlib.import_module('distutils')
File "/usr/lib64/python3.11/importlib/__init__.py", line 126, in import_module
return _bootstrap._gcd_import(name[level:], package, level)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/root/.virtualenvs/foo/lib/python3.11/site-packages/_distutils_hack/__init__.py", line 90, in find_spec
return method()
^^^^^^^^
File "/root/.virtualenvs/foo/lib/python3.11/site-packages/_distutils_hack/__init__.py", line 97, in spec_for_distutils
import importlib.abc
File "/usr/lib64/python3.11/importlib/abc.py", line 19, in <module>
from .resources.abc import ResourceReader, Traversable, TraversableResources
File "/usr/lib64/python3.11/importlib/resources/__init__.py", line 3, in <module>
from ._common import (
File "/usr/lib64/python3.11/importlib/resources/_common.py", line 3, in <module>
import tempfile
File "/usr/lib64/python3.11/tempfile.py", line 45, in <module>
from random import Random as _Random
File "/usr/lib64/python3.11/random.py", line 49, in <module>
from math import log as _log, exp as _exp, pi as _pi, e as _e, ceil as _ceil
ModuleNotFoundError: No module named 'math'This can be reproduced with a fresh virtualenv that contains a couple - in this setup it was three, but in other environments two were enough - paths added via add2virtualenv
mkvirtualenv foo
mkdir dummy1 dummy2 dummy3
add2virtualenv dummy1 dummy2 dummy3and then installing a basically empty package with a minimal pyproject.toml
echo "[project]
name = 'bar'
version = '1.0.0'
[build-system]
requires = ['setuptools']
build-backend = 'setuptools.build_meta'" > pyproject.toml
pip install .