Testing tox with tox py requires system-installed venv package

[0cjs]

Issue

It looks as if when using a Debian-supplied python3 interpreter, you must have additional OS packages installed as well, these being at least python3-venv. Cannot tox simply use virtualenv for this since, being a tox dependency, that is always available in the environment?

Environment

Debian 12, system python3 package supplying Python 3.11.2.

Output of host python pip list (Debian python3-pip is not installed):

$ pip list
bash: pip: command not found
$ pip3 list
bash: pip3: command not found

Output of top-level tox environment pip list:

$ pae tox pip list
Package       Version
------------- -------
cachetools    5.3.2
chardet       5.2.0
colorama      0.4.6
distlib       0.3.8
filelock      3.13.1
packaging     23.2
pip           23.3.2
platformdirs  4.1.0
pluggy        1.3.0
pyproject-api 1.6.1
setuptools    69.0.3
tox           4.12.1
virtualenv    20.25.0
wheel         0.42.0

I'm running the "top-level" tox in a virtual environment using pae from pactivate. This is essentially the same thing as using pipx, and python3 ~/Downloads/pipx.pyz run tox -e py -- -k test_build_wheel_external produces the same error.

Output of running tox

$ pae tox  -e py -- -k test_build_wheel_external
.pkg: _optional_hooks> python /home/cjs/.pyvirtenv/tox/.build/virtualenv/lib/python3.11/site-packages/pyproject_api/_backend.py True hatchling.build
.pkg: get_requires_for_build_wheel> python /home/cjs/.pyvirtenv/tox/.build/virtualenv/lib/python3.11/site-packages/pyproject_api/_backend.py True hatchling.build
.pkg: get_requires_for_build_editable> python /home/cjs/.pyvirtenv/tox/.build/virtualenv/lib/python3.11/site-packages/pyproject_api/_backend.py True hatchling.build
.pkg: build_wheel> python /home/cjs/.pyvirtenv/tox/.build/virtualenv/lib/python3.11/site-packages/pyproject_api/_backend.py True hatchling.build
py: install_package> python -I -m pip install --force-reinstall --no-deps /home/cjs/co/public/gh/tox-dev/tox/.tox/.tmp/package/12/tox-4.12.2.dev1+g5054a86f-py3-none-any.whl
py: commands[0]> pytest -k test_build_wheel_external
============================================================================ test session starts =============================================================================
platform linux -- Python 3.11.2, pytest-7.4.4, pluggy-1.3.0
cachedir: .tox/py/.pytest_cache
rootdir: /home/cjs/co/public/gh/tox-dev/tox
configfile: pyproject.toml
testpaths: tests
plugins: cov-4.1.0, xdist-3.5.0, time-machine-2.13.0, devpi-server-6.10.0, anyio-4.2.0, flaky-3.7.0, mock-3.12.0
collected 1690 items / 1686 deselected / 4 selected                                                                                                                          

tests/tox_env/python/virtual_env/package/test_package_cmd_builder.py F...                                                                                              [100%]

================================================================================== FAILURES ==================================================================================
_________________________________________________________________________ test_build_wheel_external __________________________________________________________________________
tests/tox_env/python/virtual_env/package/test_package_cmd_builder.py:108: in test_build_wheel_external
    result.assert_success()
        demo_pkg_inline = PosixPath('/home/cjs/co/public/gh/tox-dev/tox/tests/demo_pkg_inline')
        ini        = "\n    [testenv]\n    package = external\n    package_env = .ext\n    commands =\n        python -c 'from demo_pkg_inl...   package_glob = {envtmpdir}{/}dist{/}*.whl\n    commands =\n        pyproject-build -w . -o {envtmpdir}{/}dist\n    "
        project    = ToxProject(path=/tmp/pytest-of-cjs/pytest-10/test_build_wheel_external0/p) at 140152652576272
        result     = code: 1
cmd: /home/cjs/co/public/gh/tox-dev/tox/.tox/py/bin/python -m tox r --root /home/cjs/co/public/gh/tox-dev/tox/...failed with stopping as failed to build package
  py: FAIL code 1 (2.63 seconds)
  evaluation failed :( (2.66 seconds)

        tox_project = <function init_fixture.<locals>._init at 0x7f77d52fa480>
.tox/py/lib/python3.11/site-packages/tox/pytest.py:354: in assert_success
    assert self.success, repr(self)  # noqa: S101
E   AssertionError: code: 1
E     cmd: /home/cjs/co/public/gh/tox-dev/tox/.tox/py/bin/python -m tox r --root /home/cjs/co/public/gh/tox-dev/tox/tests/demo_pkg_inline --workdir /tmp/pytest-of-cjs/pytest-10/test_build_wheel_external0/p
E     cwd: /tmp/pytest-of-cjs/pytest-10/test_build_wheel_external0/p
E     standard output
E     .ext: install_requires /home/cjs/co/public/gh/tox-dev/tox/tests/demo_pkg_inline> python -I -m pip install build
E     .ext: install_deps /home/cjs/co/public/gh/tox-dev/tox/tests/demo_pkg_inline> python -I -m pip install build
E     .ext: commands[0] /home/cjs/co/public/gh/tox-dev/tox/tests/demo_pkg_inline> pyproject-build -w . -o /tmp/pytest-of-cjs/pytest-10/test_build_wheel_external0/p/.ext/tmp/dist
E     * Creating venv isolated environment...
E     The virtual environment was not created successfully because ensurepip is not
E     available.  On Debian/Ubuntu systems, you need to install the python3-venv
E     package using the following command.
E     
E         apt install python3.11-venv
E     
E     You may need to use sudo with that command.  After installing the python3-venv
E     package, recreate your virtual environment.
E     
E     Failing command: /tmp/build-env-l8i3vowx/bin/python3.11
E     
E     .ext: exit 1 (0.16 seconds) /home/cjs/co/public/gh/tox-dev/tox/tests/demo_pkg_inline> pyproject-build -w . -o /tmp/pytest-of-cjs/pytest-10/test_build_wheel_external0/p/.ext/tmp/dist pid=3477409
E     py: failed with stopping as failed to build package
E       py: FAIL code 1 (2.63 seconds)
E       evaluation failed :( (2.66 seconds)
E     
E   assert False
E    +  where False = code: 1\ncmd: /home/cjs/co/public/gh/tox-dev/tox/.tox/py/bin/python -m tox r --root /home/cjs/co/public/gh/tox-dev/tox/...failed with stopping as failed to build package\n  py: FAIL code 1 (2.63 seconds)\n  evaluation failed :( (2.66 seconds)\n.success
        self       = code: 1
cmd: /home/cjs/co/public/gh/tox-dev/tox/.tox/py/bin/python -m tox r --root /home/cjs/co/public/gh/tox-dev/tox/...failed with stopping as failed to build package
  py: FAIL code 1 (2.63 seconds)
  evaluation failed :( (2.66 seconds)

========================================================================== short test summary info ===========================================================================
FAILED tests/tox_env/python/virtual_env/package/test_package_cmd_builder.py::test_build_wheel_external - AssertionError: code: 1
================================================================ 1 failed, 3 passed, 1686 deselected in 3.74s ================================================================
py: exit 1 (4.61 seconds) /home/cjs/co/public/gh/tox-dev/tox> pytest -k test_build_wheel_external pid=3477284
.pkg: _exit> python /home/cjs/.pyvirtenv/tox/.build/virtualenv/lib/python3.11/site-packages/pyproject_api/_backend.py True hatchling.build
  py: FAIL code 1 (6.20=setup[1.60]+cmd[4.61] seconds)
  evaluation failed :( (6.28 seconds)

Minimal example

On your Debian system, ensure python3 is installed but python3-venv and python3-pip are not installed. In the tox source tree, use pae or pipx as described above to runtox -e py -- -k test_build_wheel_external`.

[gaborbernat]

This sounds like a bug for pyproject-build, not tox.

[0cjs]

Can you give me a rough idea of how pyproject-build is being used here so that I can try to build a test case for that? It's not clear to me what test_build_wheel_external is doing, or the location of the virtual environment that its ini = ... is creating. (I cannot find a .ext directory anywhere under the tree after running that test.)

[gaborbernat]

E .ext: commands[0] /home/cjs/co/public/gh/tox-dev/tox/tests/demo_pkg_inline> pyproject-build -w . -o /tmp/pytest-of-cjs/pytest-10/test_build_wheel_external0/p/.ext/tmp/dist

The test seems to be using it to build a wheel.