Tox can't copy non-python file while installing the module

Question

This is the tree structure of the module I'm writing the setup.py file for:

ls .

LICENSE
README.md
bin
examples
module
scratch
setup.py
tests
tox.ini

I configured my setup.py as follows:

from setuptools import setup, find_packages

setup(
    name="package_name",
    version="0.1",
    packages=find_packages(),

    install_requires=[
        # [...]
    ],

    extras_require={
        # [...]

    },

    tests_require={
        'pytest',
        'doctest'
    },

    scripts=['bin/bootstrap'],

     data_files=[
        ('license', ['LICENSE']),
     ],

    # [...]
    # could also include long_description, download_url, classifiers, etc.
)

If I install the package from my python environment (also a virtualenv)

pip install .

the LICENSE file gets correctly installed.

But running tox:

[tox]
envlist = py27, py35

[testenv]
deps = 
    pytest
    git+https://github.com/djc/couchdb-python
    docopt

commands = py.test \
    {posargs}

I get this error:

running install_data
  creating build/bdist.macosx-10.11-x86_64/wheel/leafline-0.1.data
  creating build/bdist.macosx-10.11-x86_64/wheel/leafline-0.1.data/data
  creating build/bdist.macosx-10.11-x86_64/wheel/leafline-0.1.data/data/license
  error: can't copy 'LICENSE': doesn't exist or not a regular file

Removing the data_files part from the setup.py makes tox running correctly.

Could you try to run `python setup.py install` and see what will happen? As far as I remember `pip install .` works the same as `python setup.py develop` and tox uses `install` command. — Eir Nym, Oct 21 '18 at 01:45

pradyunsg · Answer 1 · 2018-10-23T16:32:10.210

Your issue here is that setuptools is not able to find the 'LICENSE' file in the files that have been included for building the source distribution. You have 2 options, to tell setuptools to include that file (both have been pointed to here):

Add a MANIFEST.in file (like https://github.com/pypa/sampleproject/)
Use include_package_data=True in your setup.py file.

Using MANIFEST.in is often simpler and easier to verify due to https://pypi.org/project/check-manifest/, making it possible to use automation to verify that things are indeed correct (if you use a VCS like Git or SVN).

pip install . builds a wheel using python setup.py bdist_wheel which is installed by simply unpacking it appropriately, as defined in the Wheel Specification: https://www.python.org/dev/peps/pep-0427/

tox builds a source distribution using python setup.py sdist, which is then unpacked and installed using python setup.py install.

That might be a reason for the difference in behavior for you.

Bounty awarded. Nice complete answer. – Routhinator Oct 24 '18 at 15:54 — Routhinator, Oct 24 '18 at 15:54

score 0 · Answer 2 · answered Oct 21 '18 at 01:46

I have some resource files inside my packages which I use during the execution. To make setup store them in a package with python code, I use include_package_data=True and I access them using importlib.resources. You can use backport for an older Python version than 3.7 or another library.

Before each release I have a script which verifies, that all files I need are placed inside a bdist wheel to be sure that everything is on the place.

Tox can't copy non-python file while installing the module

2 Answers2