Latest pip master breaks tox

[atugushev]

Tested with tox==3.14.0 and pypa/pip@c729a84. Related to pypa/pip#7002.

Reproducer

$ cd $(mktemp -d)

$ cat setup.py
from setuptools import setup
setup()

$ cat tox.ini
[tox]
envlist = py37
[testenv]
deps = -e git+https://github.com/pypa/pip.git@ c729a84b4884511912f459f3e340367c2872f495#egg=pip
commands = pip --version

$ tox -rvv
using tox.ini: /Users/albert/Projects/test-package/tox.ini (pid 26185)
  removing /Users/albert/Projects/test-package/.tox/log
using tox-3.14.0 from /usr/local/lib/python2.7/site-packages/tox/__init__.pyc (pid 26185)
GLOB start: packaging 
GLOB sdist-make: /Users/albert/Projects/test-package/setup.py
  removing /Users/albert/Projects/test-package/.tox/dist
[26186] /Users/albert/Projects/test-package$ /usr/local/opt/python@2/bin/python2.7 setup.py sdist --formats=zip --dist-dir .tox/dist >.tox/log/GLOB-0.log
running sdist
running egg_info
writing requirements to atugushev_testpackage.egg-info/requires.txt
writing atugushev_testpackage.egg-info/PKG-INFO
writing top-level names to atugushev_testpackage.egg-info/top_level.txt
writing dependency_links to atugushev_testpackage.egg-info/dependency_links.txt
reading manifest file 'atugushev_testpackage.egg-info/SOURCES.txt'
writing manifest file 'atugushev_testpackage.egg-info/SOURCES.txt'
running check
creating atugushev-testpackage-0.1.12
creating atugushev-testpackage-0.1.12/atugushev_testpackage.egg-info
creating atugushev-testpackage-0.1.12/testpackage
copying files to atugushev-testpackage-0.1.12...
copying README.md -> atugushev-testpackage-0.1.12
copying setup.py -> atugushev-testpackage-0.1.12
copying atugushev_testpackage.egg-info/PKG-INFO -> atugushev-testpackage-0.1.12/atugushev_testpackage.egg-info
copying atugushev_testpackage.egg-info/SOURCES.txt -> atugushev-testpackage-0.1.12/atugushev_testpackage.egg-info
copying atugushev_testpackage.egg-info/dependency_links.txt -> atugushev-testpackage-0.1.12/atugushev_testpackage.egg-info
copying atugushev_testpackage.egg-info/not-zip-safe -> atugushev-testpackage-0.1.12/atugushev_testpackage.egg-info
copying atugushev_testpackage.egg-info/requires.txt -> atugushev-testpackage-0.1.12/atugushev_testpackage.egg-info
copying atugushev_testpackage.egg-info/top_level.txt -> atugushev-testpackage-0.1.12/atugushev_testpackage.egg-info
copying testpackage/__init__.py -> atugushev-testpackage-0.1.12/testpackage
Writing atugushev-testpackage-0.1.12/setup.cfg
creating '.tox/dist/atugushev-testpackage-0.1.12.zip' and adding 'atugushev-testpackage-0.1.12' to it
adding 'atugushev-testpackage-0.1.12/PKG-INFO'
adding 'atugushev-testpackage-0.1.12/README.md'
adding 'atugushev-testpackage-0.1.12/setup.py'
adding 'atugushev-testpackage-0.1.12/setup.cfg'
adding 'atugushev-testpackage-0.1.12/atugushev_testpackage.egg-info/PKG-INFO'
adding 'atugushev-testpackage-0.1.12/atugushev_testpackage.egg-info/not-zip-safe'
adding 'atugushev-testpackage-0.1.12/atugushev_testpackage.egg-info/SOURCES.txt'
adding 'atugushev-testpackage-0.1.12/atugushev_testpackage.egg-info/requires.txt'
adding 'atugushev-testpackage-0.1.12/atugushev_testpackage.egg-info/top_level.txt'
adding 'atugushev-testpackage-0.1.12/atugushev_testpackage.egg-info/dependency_links.txt'
adding 'atugushev-testpackage-0.1.12/testpackage/__init__.py'
removing 'atugushev-testpackage-0.1.12' (and everything under it)

GLOB finish: packaging  after 0.32 seconds
copying new sdistfile to '/Users/albert/.tox/distshare/atugushev-testpackage-0.1.12.zip'
package .tmp/package/1/atugushev-testpackage-0.1.12.zip links to dist/atugushev-testpackage-0.1.12.zip (/Users/albert/Projects/test-package/.tox)
py37 start: getenv /Users/albert/Projects/test-package/.tox/py37
py37 cannot reuse: -r flag
py37 recreate: /Users/albert/Projects/test-package/.tox/py37
python3.7 (/Users/albert/Projects/test-package/.venv/bin/python3.7) is {u'executable': u'/Users/albert/Projects/test-package/.venv/bin/python3.7', u'name': u'python', u'version_info': [3, 7, 3, u'final', 0], u'sysplatform': u'darwin', u'version': u'3.7.3 (default, Mar 27 2019, 09:23:15) \n[Clang 10.0.1 (clang-1001.0.46.3)]', u'is_64': True}
py37 uses /Users/albert/Projects/test-package/.venv/bin/python3.7
  removing /Users/albert/Projects/test-package/.tox/py37
setting PATH=/Users/albert/Projects/test-package/.tox/py37/bin:/Users/albert/Projects/test-package/.venv/bin:/usr/local/opt/node@10/bin:/Users/albert/.gem/bin:/Users/albert/.pyenv/shims:/Users/albert/.pyenv/bin:/usr/local/opt/postgresql@10/bin:/usr/local/opt/gettext/bin:/usr/local/sbin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/opt/X11/bin
[26194] /Users/albert/Projects/test-package/.tox$ /usr/local/opt/python@2/bin/python2.7 -m virtualenv --no-download --python /Users/albert/Projects/test-package/.venv/bin/python3.7 py37
Running virtualenv with interpreter /Users/albert/Projects/test-package/.venv/bin/python3.7
Already using interpreter /Users/albert/Projects/test-package/.venv/bin/python3.7
Using real prefix '/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7'
New python executable in /Users/albert/Projects/test-package/.tox/py37/bin/python3.7
Also creating executable in /Users/albert/Projects/test-package/.tox/py37/bin/python
Installing setuptools, pip, wheel...
done.
py37 installdeps: -egit+https://github.com/pypa/pip.git@c729a84b4884511912f459f3e340367c2872f495#egg=pip
setting PATH=/Users/albert/Projects/test-package/.tox/py37/bin:/Users/albert/Projects/test-package/.venv/bin:/usr/local/opt/node@10/bin:/Users/albert/.gem/bin:/Users/albert/.pyenv/shims:/Users/albert/.pyenv/bin:/usr/local/opt/postgresql@10/bin:/usr/local/opt/gettext/bin:/usr/local/sbin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/opt/X11/bin
[26215] /Users/albert/Projects/test-package$ /Users/albert/Projects/test-package/.tox/py37/bin/python -m pip install '-egit+https://github.com/pypa/pip.git@c729a84b4884511912f459f3e340367c2872f495#egg=pip'
Obtaining pip from git+https://github.com/pypa/pip.git@c729a84b4884511912f459f3e340367c2872f495#egg=pip
  Cloning https://github.com/pypa/pip.git (to revision c729a84b4884511912f459f3e340367c2872f495) to ./.tox/py37/src/pip
  Running command git clone -q https://github.com/pypa/pip.git /Users/albert/Projects/test-package/.tox/py37/src/pip
  Installing build dependencies ... done
  Getting requirements to build wheel ... done
    Preparing wheel metadata ... done
Installing collected packages: pip
  Found existing installation: pip 19.2.3
    Uninstalling pip-19.2.3:
      Successfully uninstalled pip-19.2.3
  Running setup.py develop for pip
Successfully installed pip
py37 finish: getenv /Users/albert/Projects/test-package/.tox/py37 after 19.67 seconds
py37 start: installpkg /Users/albert/Projects/test-package/.tox/.tmp/package/1/atugushev-testpackage-0.1.12.zip
py37 inst: /Users/albert/Projects/test-package/.tox/.tmp/package/1/atugushev-testpackage-0.1.12.zip
write config to /Users/albert/Projects/test-package/.tox/py37/.tox-config1 as '6ca0676fb0398a654a2483eb31e082f6cfba52beb10b4af1387e8e3741382f9a /Users/albert/Projects/test-package/.venv/bin/python3.7\n3.14.0 0 0 0\n00000000000000000000000000000000 -egit+https://github.com/pypa/pip.git@c729a84b4884511912f459f3e340367c2872f495#egg=pip'
setting PATH=/Users/albert/Projects/test-package/.tox/py37/bin:/Users/albert/Projects/test-package/.venv/bin:/usr/local/opt/node@10/bin:/Users/albert/.gem/bin:/Users/albert/.pyenv/shims:/Users/albert/.pyenv/bin:/usr/local/opt/postgresql@10/bin:/usr/local/opt/gettext/bin:/usr/local/sbin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/opt/X11/bin
[26282] /Users/albert/Projects/test-package$ /Users/albert/Projects/test-package/.tox/py37/bin/python -m pip install --exists-action w .tox/.tmp/package/1/atugushev-testpackage-0.1.12.zip
ERROR: Exception:
Traceback (most recent call last):
  File "/Users/albert/Projects/test-package/.tox/py37/src/pip/src/pip/_internal/cli/base_command.py", line 153, in _main
    status = self.run(options, args)
  File "/Users/albert/Projects/test-package/.tox/py37/src/pip/src/pip/_internal/commands/install.py", line 302, in run
    isolated_mode=options.isolated_mode,
  File "/Users/albert/Projects/test-package/.tox/py37/src/pip/src/pip/_internal/commands/install.py", line 638, in decide_user_install
    assert use_user_site is None
AssertionError
ERROR: invocation failed (exit code 2)
py37 finish: installpkg /Users/albert/Projects/test-package/.tox/.tmp/package/1/atugushev-testpackage-0.1.12.zip after 0.70 seconds
___________________________________________________ summary ___________________________________________________
ERROR:   py37: InvocationError for command /Users/albert/Projects/test-package/.tox/py37/bin/python -m pip install --exists-action w .tox/.tmp/package/1/atugushev-testpackage-0.1.12.zip (exited with code 2)
cleanup /Users/albert/Projects/test-package/.tox/.tmp/package/1/atugushev-testpackage-0.1.12.zip

[atugushev]

Fixed in pypa/pip#7258.

[atugushev]

@gaborbernat is tox/virtualenv use a separate pip.conf with user=true, because it was the root of the issue? Just out of the curiosity.

[gaborbernat]

No different configuration file, but we do pass in our own flags. So depends.

[atugushev]

Yeah, via environment variable:

tox/src/tox/venv.py

Lines 428 to 429 in 3980da7

	# installing packages at user level may mean we're not installing inside the venv
	env["PIP_USER"] = "0"