ModuleNotFoundError：没有名为“flake8”的模块

Question

这是对这个问题很重要的文件部分：

.
├── .env
├── tox.ini
├── requirements-dev.txt
└── tests/
    ├── test_blocking.py
    └── test_async.py

.env 示例

token = # Replace this with your API token
base_url = # Proxy server to handle requests to API due to IP limitations

毒物

[tox]
envlist = py35,py36,py37,py38

[testenv]
changedir = tests
deps = -r{toxinidir}/requirements-dev.txt
sitepackages = true
whitelist_externals =
    flake8
    pytest
commands =
    flake8
    pytest
passenv =
    token
    base_url

[flake8]
max-line-length=120
exclude = __init__.py,.tox
ignore = E252,E302,E731,W605

需求-dev.txt

asynctest
flake8
pluggy>=0.12.0,<1.0.0
pytest
pytest-asyncio
python-dotenv
tox-travis

使用来自测试的文件/一切正常，它们适用于其他版本

如果，从项目的主目录，在 cmd 我运行这样一个命令tox -e py38

我得到这个 output：

GLOB sdist-make: C:\Python\projects\brawlstats\setup.py
py38 inst-nodeps: C:\Python\projects\brawlstats\.tox\.tmp\package\1\brawlstats-4.0.3.zip
py38 installed: absl-py==0.9.0,aiohttp==3.6.2,alabaster==0.7.12,altgraph==0.17,apng==0.3.4,appdirs==1.4.3,argh==0.26.2,asgiref==3.2.3,astroid==2.3.3,astunparse==1.6.3,async-timeout==3.0.1,asynctest==0.13.0,atomicwrites==1.3.0,attrs==19.3.0,audio2numpy==0.1.2,autopep8==1.5.1,Babel==2.8.0,backcall==0.1.0,bandit==1.6.2,beautifulsoup4==4.9.0,bleach==3.1.4,blis==0.4.1,brawlstats==4.0.3,bs4==0.0.1,cachetools==4.0.0,catalogue==1.0.0,certifi==2019.11.28,cfgv==3.1.0,chardet==3.0.4,click==7.1.1,colorama==0.4.1,colorlog==4.1.0,colour==0.1.5,cPython==0.0.5,cycler==0.10.0,cymem==2.0.3,decorator==4.4.1,defusedxml==0.6.0,distlib==0.3.0,Django==3.0.3,dnspython==1.16.0,docutils==0.16,dodgy==0.2.1,EasyProcess==0.2.10,entrypoint2==0.2,entrypoints==0.3,eventlet==0.25.2,fbs==0.8.6,feedparser==5.2.1,ffmpeg==1.4,filelock==3.0.12,flake8==3.8.3,flake8-polyfill==1.0.2,future==0.18.2,futures==3.1.1,gast==0.3.3,gitdb2==2.0.6,GitPython==2.1.15,google-api-core==1.16.0,google-api-python-client==1.8.2,google-auth==1.11.3,google-auth-httplib2==0.0.3,google-auth-oauthlib==0.4.1,google-cloud-core==1.3.0,google-cloud-translate==2.0.1,google-pasta==0.2.0,googleapis-common-protos==1.51.0,googletrans==2.4.0,goslate==1.5.1,greenlet==0.4.16,grpcio==1.27.2,h5py==2.10.0,httplib2==0.15.0,identify==1.4.11,idna==2.9,imagesize==1.2.0,ipykernel==5.2.1,ipython==7.13.0,ipython-genutils==0.2.0,isort==4.3.21,jedi==0.17.0,Jinja2==2.11.2,json5==0.9.4,jsonschema==3.2.0,jupyter-client==6.1.3,jupyter-core==4.6.3,jupyterlab==2.1.1,jupyterlab-server==1.1.1,Keras-Preprocessing==1.1.2,kivy-deps.angle==0.1.10,kivy-deps.glew==0.1.12,kivy-deps.gstreamer==0.1.18,kivy-deps.sdl2==0.1.23,Kivy-Garden==0.1.4,kiwisolver==1.1.0,lazy-object-proxy==1.4.3,livereload==2.6.2,llvmlite==0.33.0,lxml==4.5.0,macholib==1.14,mando==0.6.4,Markdown==3.2.2,MarkupSafe==1.1.1,matplotlib==3.1.3,mccabe==0.6.1,mistune==0.8.4,monotonic==1.5,more-itertools==8.2.0,mss==5.0.0,multidict==4.7.5,murmurhash==1.0.2,mypy==0.782,mypy-extensions==0.4.3,nbconvert==5.6.1,nbformat==4.4.0,networkx==2.4,nodeenv==1.3.5,notebook==6.0.3,Nuitka==0.6.8.4,numba==0.50.0,numpy==1.18.1,oauth2client==4.1.3,oauthlib==3.1.0,opencv-python==4.2.0.32,opt-einsum==3.2.1,packaging==20.3,pandas==1.0.3,pandocfilters==1.4.2,parso==0.7.0,pathtools==0.1.2,pbr==5.4.5,pefile==2019.4.18,pep8==1.7.1,pep8-naming==0.4.1,pickleshare==0.7.5,Pillow==7.0.0,plac==1.1.3,plotly==4.8.0,pluggy==0.13.1,port-for==0.3.1,pre-commit==2.2.0,preshed==3.0.2,progress==1.4,prometheus-client==0.7.1,prompt-toolkit==3.0.5,prospector==1.2.0,protobuf==3.11.3,py==1.8.1,pyasn1==0.4.8,pyasn1-modules==0.2.8,pycodestyle==2.6.0,pydocstyle==5.0.2,PyDrive==1.3.1,pydub==0.23.1,pyflakes==2.2.0,pygame==1.9.6,pyglet==1.5.2,Pygments==2.6.1,PyInstaller==3.4,pylama==7.7.1,pylint==2.4.4,pylint-celery==0.3,pylint-django==2.0.12,pylint-flask==0.6,pylint-plugin-utils==0.6,pymongo==3.10.1,pynput==1.6.6,pyparsing==2.4.6,pypiwin32==223,PyQt-builder==1.2.0,PyQt5==5.13.2,PyQt5-sip==12.7.1,pyqt5-tools==5.13.2.1.6rc1,pyrsistent==0.16.0,pyscreenshot==1.0,PySimpleGUI==4.18.0,pytest==5.4.1,pytest-asyncio==0.14.0,python-box==4.2.2,python-dateutil==2.8.1,python-dotenv==0.12.0,python-statemachine==0.8.0,pytz==2019.3,pywin32==227,pywin32-ctypes==0.2.0,pywinpty==0.5.7,PyYAML==5.3,pyzmq==19.0.0,qimage2ndarray==1.8.3,radon==4.0.0,requests==2.23.0,requests-oauthlib==1.3.0,requirements-detector==0.7,retrying==1.3.3,rope==0.16.0,rsa==4.0,rstcheck==3.3.1,ruamel.yaml==0.16.10,ruamel.yaml.clib==0.2.0,scipy==1.4.1,selenium==3.141.0,Send2Trash==1.5.0,setoptconf==0.2.0,simpleaudio==1.0.4,sip==5.1.1,six==1.14.0,smmap==3.0.4,smmap2==3.0.1,snowballstemmer==2.0.0,soupsieve==2.0,spacy==2.2.4,Sphinx==3.1.1,sphinx-autobuild==0.7.1,sphinxcontrib-applehelp==1.0.2,sphinxcontrib-devhelp==1.0.2,sphinxcontrib-htmlhelp==1.0.3,sphinxcontrib-jsmath==1.0.1,sphinxcontrib-qthelp==1.0.3,sphinxcontrib-serializinghtml==1.1.4,sqlparse==0.3.0,srsly==1.0.2,stevedore==2.0.1,tabulate==0.8.7,tensorboard==2.2.1,tensorboard-plugin-wit==1.6.0.post3,tensorflow==2.2.0,tensorflow-estimator==2.2.0,tensorflow-hub==0.8.0,termcolor==1.1.0,terminado==0.8.3,testpath==0.4.4,thinc==7.4.0,tkcalendar==1.6.1,toml==0.10.0,tornado==6.0.4,tox==3.14.5,tox-travis==0.12,tqdm==4.46.0,traitlets==4.3.3,translate==3.5.0,typed-ast==1.4.1,typing-extensions==3.7.4.2,uritemplate==3.0.1,urllib3==1.25.8,virtualenv==20.0.15,vk-api==11.8.0,wasabi==0.6.0,watchdog==0.10.3,wcwidth==0.1.9,webencodings==0.5.1,Werkzeug==1.0.1,wily==1.16.0,wrapt==1.11.2,wxPython==4.0.7.post2,yarl==1.4.2
py38 run-test-pre: PYTHONHASHSEED='87'
py38 run-test: commands[0] | flake8
Traceback (most recent call last):
  File "c:\program files\python38\lib\runpy.py", line 193, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "c:\program files\python38\lib\runpy.py", line 86, in _run_code
    exec(code, run_globals)
  File "C:\Users\ASUS\AppData\Roaming\Python\Python38\Scripts\flake8.EXE\__main__.py", line 4, in <module>
ModuleNotFoundError: No module named 'flake8'
ERROR: InvocationError for command 'C:\Users\ASUS\AppData\Roaming\Python\Python38\Scripts\flake8.EXE' (exited with code 1)
_________________________________________________________________________________ summary _________________________________________________________________________________
ERROR:   py38: commands failed

如果我运行pip3.8 show flake8

我得到这个 output：

Name: flake8
Version: 3.8.3
Summary: the modular source code checker: pep8 pyflakes and co
Home-page: https://gitlab.com/pycqa/flake8
Author: Tarek Ziade
Author-email: tarek@ziade.org
License: MIT
Location: c:\users\asus\appdata\roaming\python\python38\site-packages
Requires: pycodestyle, mccabe, pyflakes
Required-by: flake8-polyfill

我究竟做错了什么？ 在 py 3.7 上一切正常。 也许我的毒素不好？ 我应该怎么办？ 请帮忙！

Answer 1

我对如此广泛的报告表示赞赏。 您的问题可能在于您正在进行的这种奇怪的设置。

# This alows for packages to be accessed from the **globally** installed Python (NOT the tox env). 
sitepackages = True
# This alows for commands to be used available outside tox. Typically used for non-python callables. 
whitelist_externals =
    flake8
    pytest
# Redundant || the context change is confusing - try to use everything from the project root. 
changedir = tests

• 站点包配置值
• 更改目录
• 白名单外部

所以简而言之，您没有使用tox依赖项。 您正在尝试使用全局包，而不是安装了tox的包。 一些推测，这可能会导致 python 3.8 全局可用包中的一些导入冲突。

尝试以下操作：

[tox]
envlist = py35,py36,py37,py38

[testenv]
deps = -r{toxinidir}/requirements-dev.txt
commands =
    flake8 {{folders}}
    pytest 
passenv =
    token
    base_url

[flake8]
max-line-length=120
exclude = __init__.py
ignore = E252,E302,E731,W605

PS。 将 {{folders}} 替换为您的目录（IES）关闭代码，通常比排除各种目录（将来可能会自动生成）更容易。 我通常有flake8 src tests 。