tox throws setuptools error

[mleveck]

I can run the tests via pytest just fine. But attempting tox -3 py38 as the README.md suggests results in the error below. I'm happy to debug on my own and even make a PR if this is a general issue.

But before I go further, does this happen on others' machines, or just mine? (error message suggests it's shouldn't be setup dependent as it's complaining about the directory layout. But I just want to make sure the error message isn't leading me astray)

(env) Matthews-MacBook-Pro:pyrsistent mleveck$ tox -e py38
GLOB sdist-make: /Users/mleveck/src/pyrsistent/setup.py
py38 inst-nodeps: /Users/mleveck/src/pyrsistent/.tox/.tmp/package/1/pyrsistent-0.18.1.zip
py38 installed: pyrsistent @ file:///Users/mleveck/src/pyrsistent/.tox/.tmp/package/1/pyrsistent-0.18.1.zip
py38 run-test-pre: PYTHONHASHSEED='1316811237'
py38 run-test: commands[0] | python /Users/mleveck/src/pyrsistent/setup.py test
/Users/mleveck/src/pyrsistent/.tox/py38/lib/python3.8/site-packages/setuptools/installer.py:27: SetuptoolsDeprecationWarning: setuptools.installer is deprecated. Requirements should be satisfied by a PEP 517 installer.
  warnings.warn(
running pytest
No parent package detected, impossible to derive `name`
error: Multiple top-level packages discovered in a flat-layout: ['pyrsistent', 'performance_suites'].

To avoid accidental inclusion of unwanted files or directories,
setuptools will not proceed with this build.

If you are trying to create a single distribution with multiple packages
on purpose, you should not rely on automatic discovery.
Instead, consider the following options:

1. set up custom discovery (`find` directive with `include` or `exclude`)
2. use a `src-layout`
3. explicitly set `py_modules` or `packages` with a list of names

To find more information, look for "package discovery" on setuptools docs.
ERROR: InvocationError for command /Users/mleveck/src/pyrsistent/.tox/py38/bin/python setup.py test (exited with code 1)
__________________________________________________________________________________ summary ___________________________________________________________________________________
ERROR:   py38: commands failed

[tobgu]

Thanks for reporting this!

It seems to be a general problem with many packages after a recent update in setuptools, see pypa/setuptools#3197. I believe it somehow falls back to autodetecting the package ignoring the packages directive in setup.py because there is also a pyproject.toml. I made a quick fix now by renaming the conflicting directory to a (better) name that is ignored by the autodetection.