Python 3.9 + 20.0.6: No module named pip

[hugovk]

Issue

Describe what's the expected behaviour and what you're observing.

Using tox with Python 3.9-dev and nightly on Travis CI is failing with "No module named pip".

This started with virtualenv 20.0.6. It worked fine with virtualenv 20.0.5.

Python 3.6-3.8 and their -dev versions are also fine with 20.0.6.

language: python
cache:
  pip: true
  directories:
    - $HOME/.cache/pre-commit

matrix:
  fast_finish: true
  include:
    - python: nightly
    - python: 3.9-dev
    - python: 3.8-dev
    - python: 3.7-dev
    - python: 3.6-dev
    - python: 3.8
      env: TOXENV=lint
    - python: 3.8
    - python: 3.7
    - python: 3.6

install:
  - pip install -U pip
  - pip install -U tox-travis

script:
  - tox

py39 create: /home/travis/build/hugovk/pypistats/.tox/py39
py39 inst: /home/travis/build/hugovk/pypistats/.tox/.tmp/package/1/pypistats-0.10.2.dev2.zip
ERROR: invocation failed (exit code 1), logfile: /home/travis/build/hugovk/pypistats/.tox/py39/log/py39-1.log
================================== log start ===================================
Processing ./.tox/.tmp/package/1/pypistats-0.10.2.dev2.zip
  Installing build dependencies: started
  Installing build dependencies: finished with status 'done'
  Getting requirements to build wheel: started
  Getting requirements to build wheel: finished with status 'done'
  Installing backend dependencies: started
  Installing backend dependencies: finished with status 'done'
    Preparing wheel metadata: started
    Preparing wheel metadata: finished with status 'error'
    ERROR: Command errored out with exit status 1:
     command: /home/travis/build/hugovk/pypistats/.tox/py39/bin/python /home/travis/build/hugovk/pypistats/.tox/py39/lib/python3.9/site-packages/pip/_vendor/pep517/_in_process.py prepare_metadata_for_build_wheel /tmp/tmpqsagygxr
         cwd: /tmp/pip-req-build-citr7lc7
    Complete output (42 lines):
    /home/travis/build/hugovk/pypistats/.tox/py39/bin/python: No module named pip
    Traceback (most recent call last):
      File "/home/travis/build/hugovk/pypistats/.tox/py39/lib/python3.9/site-packages/setuptools/installer.py", line 128, in fetch_build_egg
        subprocess.check_call(cmd)
      File "/opt/python/3.9-dev/lib/python3.9/subprocess.py", line 372, in check_call
        raise CalledProcessError(retcode, cmd)
    subprocess.CalledProcessError: Command '['/home/travis/build/hugovk/pypistats/.tox/py39/bin/python', '-m', 'pip', '--disable-pip-version-check', 'wheel', '--no-deps', '-w', '/tmp/tmp5dnb6xs7', '--quiet', 'setuptools_scm']' returned non-zero exit status 1.
    
    During handling of the above exception, another exception occurred:
    
    Traceback (most recent call last):
      File "/home/travis/build/hugovk/pypistats/.tox/py39/lib/python3.9/site-packages/pip/_vendor/pep517/_in_process.py", line 257, in <module>
        main()
      File "/home/travis/build/hugovk/pypistats/.tox/py39/lib/python3.9/site-packages/pip/_vendor/pep517/_in_process.py", line 240, in main
        json_out['return_val'] = hook(**hook_input['kwargs'])
      File "/home/travis/build/hugovk/pypistats/.tox/py39/lib/python3.9/site-packages/pip/_vendor/pep517/_in_process.py", line 110, in prepare_metadata_for_build_wheel
        return hook(metadata_directory, config_settings)
      File "/home/travis/build/hugovk/pypistats/.tox/py39/lib/python3.9/site-packages/setuptools/build_meta.py", line 158, in prepare_metadata_for_build_wheel
        self.run_setup()
      File "/home/travis/build/hugovk/pypistats/.tox/py39/lib/python3.9/site-packages/setuptools/build_meta.py", line 249, in run_setup
        super(_BuildMetaLegacyBackend,
      File "/home/travis/build/hugovk/pypistats/.tox/py39/lib/python3.9/site-packages/setuptools/build_meta.py", line 143, in run_setup
        exec(compile(code, __file__, 'exec'), locals())
      File "setup.py", line 13, in <module>
        setup(
      File "/home/travis/build/hugovk/pypistats/.tox/py39/lib/python3.9/site-packages/setuptools/__init__.py", line 143, in setup
        _install_setup_requires(attrs)
      File "/home/travis/build/hugovk/pypistats/.tox/py39/lib/python3.9/site-packages/setuptools/__init__.py", line 138, in _install_setup_requires
        dist.fetch_build_eggs(dist.setup_requires)
      File "/home/travis/build/hugovk/pypistats/.tox/py39/lib/python3.9/site-packages/setuptools/dist.py", line 718, in fetch_build_eggs
        resolved_dists = pkg_resources.working_set.resolve(
      File "/home/travis/build/hugovk/pypistats/.tox/py39/lib/python3.9/site-packages/pkg_resources/__init__.py", line 781, in resolve
        dist = best[req.key] = env.best_match(
      File "/home/travis/build/hugovk/pypistats/.tox/py39/lib/python3.9/site-packages/pkg_resources/__init__.py", line 1066, in best_match
        return self.obtain(req, installer)
      File "/home/travis/build/hugovk/pypistats/.tox/py39/lib/python3.9/site-packages/pkg_resources/__init__.py", line 1078, in obtain
        return installer(requirement)
      File "/home/travis/build/hugovk/pypistats/.tox/py39/lib/python3.9/site-packages/setuptools/dist.py", line 777, in fetch_build_egg
        return fetch_build_egg(self, req)
      File "/home/travis/build/hugovk/pypistats/.tox/py39/lib/python3.9/site-packages/setuptools/installer.py", line 130, in fetch_build_egg
        raise DistutilsError(str(e))
    distutils.errors.DistutilsError: Command '['/home/travis/build/hugovk/pypistats/.tox/py39/bin/python', '-m', 'pip', '--disable-pip-version-check', 'wheel', '--no-deps', '-w', '/tmp/tmp5dnb6xs7', '--quiet', 'setuptools_scm']' returned non-zero exit status 1.
    ----------------------------------------
ERROR: Command errored out with exit status 1: /home/travis/build/hugovk/pypistats/.tox/py39/bin/python /home/travis/build/hugovk/pypistats/.tox/py39/lib/python3.9/site-packages/pip/_vendor/pep517/_in_process.py prepare_metadata_for_build_wheel /tmp/tmpqsagygxr Check the logs for full command output.

=================================== log end ====================================

https://travis-ci.org/hugovk/pypistats/builds/655722106

Last passing build: https://travis-ci.org/hugovk/pypistats/builds/654501366

Can reproduce locally with Python 3.9.0a2+ and 20.0.6.

Environment

Provide at least:

• OS: Ubuntu 16.04.6 LTS Xenial
• pip list of the host python where virtualenv is installed:

$ pip list
Package          Version   
---------------- ----------
atomicwrites     1.3.0     
attrs            19.3.0    
certifi          2019.9.11 
filelock         3.0.12    
mock             3.0.5     
more-itertools   7.2.0     
nose             1.3.7     
numpy            1.17.2    
packaging        19.2      
pip              20.0.2    
pipenv           2018.11.26
pluggy           0.13.0    
py               1.8.0     
pyparsing        2.4.2     
pytest           5.2.1     
setuptools       41.4.0    
six              1.14.0    
toml             0.10.0    
tox              3.14.5    
tox-travis       0.12      
virtualenv       16.7.5    
virtualenv-clone 0.5.3     
wcwidth          0.1.7     
wheel            0.33.6 

Output of the virtual environment creation

Make sure to run the creation with -vvv --with-traceback:

Using tox, how should I run this?

[hugovk]

Can reproduce locally with Python 3.9.0a2+ and 20.0.6.

Cannot reproduce locally with Python 3.9.0a2+ and 20.0.7.

And cannot reproduce on Travis when forcing an update:

pip install -U "virtualenv>=20.0.7"

https://travis-ci.org/hugovk/pypistats/builds/655728528

Sorry for the false alarm! Hopefully the Travis dev version will be rebuilt with 20.0.7 within the next 24 hours.

[gaborbernat]

This is duplicate of #1669, which is upstream bug pypa/pip#7778