usercustomize.py + middle print statement + sitepackages = True creates error after successful tox run

[Cielquan]

Hi,
this issue is strongly related to #1569 and uses its context as a base for this issue. But its another bug with the same root maybe?

When I set up the usercustomize.py file mentioned in the other issue I not only added a print() at the beginning but also when the import was successful:

try:
    from devtools import debug
except ImportError:
    pass
else:
    print('### devtool\'s debug enabled')
    __builtins__['debug'] = debug

When I now also add devtools to the deps of the env, so that it can be imported successfully I get the traceback shown below.

tox.ini:

[tox]
skipsdist = True

[testenv:dev]
basepython = python3.8
deps = devtools[pygments]>=0.5.1,<0.6
sitepackages = True

Traceback:

$ tox -e dev -r
dev recreate: /home/krys/Python_Projects/.testing/.tox/dev
dev installdeps: devtools[pygments]>=0.5.1,<0.6
_________________________________________________________________ summary __________________________________________________________________
  dev: commands succeeded
  congratulations :)
Traceback (most recent call last):
  File "/home/krys/bin/tox", line 8, in <module>
    sys.exit(cmdline())
  File "/home/krys/.venvs/tox/lib/python3.8/site-packages/tox/session/__init__.py", line 44, in cmdline
    main(args)
  File "/home/krys/.venvs/tox/lib/python3.8/site-packages/tox/session/__init__.py", line 68, in main
    exit_code = session.runcommand()
  File "/home/krys/.venvs/tox/lib/python3.8/site-packages/tox/session/__init__.py", line 194, in runcommand
    return self.subcommand_test()
  File "/home/krys/.venvs/tox/lib/python3.8/site-packages/tox/session/__init__.py", line 222, in subcommand_test
    run_sequential(self.config, self.venv_dict)
  File "/home/krys/.venvs/tox/lib/python3.8/site-packages/tox/session/commands/run/sequential.py", line 9, in run_sequential
    if venv.setupenv():
  File "/home/krys/.venvs/tox/lib/python3.8/site-packages/tox/venv.py", line 621, in setupenv
    envlog.set_python_info(command_path)
  File "/home/krys/.venvs/tox/lib/python3.8/site-packages/tox/logs/env.py", line 18, in set_python_info
    answer["executable"] = python_executable
TypeError: 'NoneType' object does not support item assignment
*** Exit Code: 1 ***

As soon as I remove the print() from the usercustomize.py file everything works just fine.

[JulienPalard]

Happened to me on Windows (github workflow).

Traceback

Traceback (most recent call last):
  File "c:\hostedtoolcache\windows\python\3.6.8\x64\lib\runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "c:\hostedtoolcache\windows\python\3.6.8\x64\lib\runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "C:\hostedtoolcache\windows\Python\3.6.8\x64\Scripts\tox.exe\__main__.py", line 7, in <module>
  File "c:\hostedtoolcache\windows\python\3.6.8\x64\lib\site-packages\tox\session\__init__.py", line 44, in cmdline
    main(args)
  File "c:\hostedtoolcache\windows\python\3.6.8\x64\lib\site-packages\tox\session\__init__.py", line 69, in main
    exit_code = session.runcommand()
  File "c:\hostedtoolcache\windows\python\3.6.8\x64\lib\site-packages\tox\session\__init__.py", line 197, in runcommand
    return self.subcommand_test()
  File "c:\hostedtoolcache\windows\python\3.6.8\x64\lib\site-packages\tox\session\__init__.py", line 213, in subcommand_test
    venv.package = self.hook.tox_package(session=self, venv=venv)
  File "c:\hostedtoolcache\windows\python\3.6.8\x64\lib\site-packages\pluggy\hooks.py", line 286, in __call__
    return self._hookexec(self, self.get_hookimpls(), kwargs)
  File "c:\hostedtoolcache\windows\python\3.6.8\x64\lib\site-packages\pluggy\manager.py", line 93, in _hookexec
    return self._inner_hookexec(hook, methods, kwargs)
  File "c:\hostedtoolcache\windows\python\3.6.8\x64\lib\site-packages\pluggy\manager.py", line 87, in <lambda>
    firstresult=hook.spec.opts.get("firstresult") if hook.spec else False,
  File "c:\hostedtoolcache\windows\python\3.6.8\x64\lib\site-packages\pluggy\callers.py", line 208, in _multicall
    return outcome.get_result()
  File "c:\hostedtoolcache\windows\python\3.6.8\x64\lib\site-packages\pluggy\callers.py", line 80, in get_result
    raise ex[1].with_traceback(ex[2])
  File "c:\hostedtoolcache\windows\python\3.6.8\x64\lib\site-packages\pluggy\callers.py", line 187, in _multicall
    res = hook_impl.function(*args)
  File "c:\hostedtoolcache\windows\python\3.6.8\x64\lib\site-packages\tox\package\__init__.py", line 16, in tox_package
    session.package, session.dist = get_package(session)
  File "c:\hostedtoolcache\windows\python\3.6.8\x64\lib\site-packages\tox\package\__init__.py", line 29, in get_package
    package = acquire_package(config, session)
  File "c:\hostedtoolcache\windows\python\3.6.8\x64\lib\site-packages\tox\package\__init__.py", line 40, in acquire_package
    path = build_package(config, session)
  File "c:\hostedtoolcache\windows\python\3.6.8\x64\lib\site-packages\tox\package\builder\__init__.py", line 9, in build_package
    return build(config, session)
  File "c:\hostedtoolcache\windows\python\3.6.8\x64\lib\site-packages\tox\package\builder\isolated.py", line 32, in build
    if package_venv.setupenv():
  File "c:\hostedtoolcache\windows\python\3.6.8\x64\lib\site-packages\tox\venv.py", line 645, in setupenv
    envlog.set_python_info(command_path)
  File "c:\hostedtoolcache\windows\python\3.6.8\x64\lib\site-packages\tox\logs\env.py", line 18, in set_python_info
    answer["executable"] = python_executable
TypeError: 'NoneType' object does not support item assignment

[Cielquan]

In the meantime I switched to another way to add devtools.debug to the python builtins (my original goal).

Now I create a filename.pth file inside the venv's site-packages directory which only imports a filename.py at the same place. The latter one bears the python logic I want to run on python start-up. I just saw that virtualenv uses the same hack.

I also just tested it with a print() and it seems to work for tox. But it fucks poetry up which I run via nox which itself seems to be unaffected.

[JulienPalard]

Happened to me on Windows (github workflow).

I don't know if github changed something of if tox fixed it, but the traceback I pasted previously does no longer happen.

[gaborbernat]

This shouldn't be a case anymore in tox 4, no plan to address it from our side unless someone creates a PR for it.