Errors in python distributors [duplicate]

Question

This question already has answers here:

python3: ImportError: No module named xxxx [duplicate] (1 answer)

Changes in import statement python3 (4 answers)

ImportError : Attempted relative import with no known parent package [duplicate] (7 answers)

Closed 3 years ago.

The following operations is under Win10:

1. the dictionary structure:

│ LICENSE
│ README.md
│ setup.py
│
└─dlpk
 a.py
 b.py
 __init__.py

2. the contents of the files:

the __init__.py is empty.

# b.py:
from a import A
# a.py:
class A:
 pass
# setup.py:
import setuptools
with open("README.md", "r", encoding="utf-8") as fh:
 long_description = fh.read()
setuptools.setup(
 name="testDL-DeaL",
 version="0.0.9",
 author="Dai Ling",
 author_email="[email protected]",
 description="error report",
 long_description=long_description,
 long_description_content_type="text/markdown",
 url="https://github.com/dailing57/DLex",
 classifiers=[
 "Programming Language :: Python :: 3",
 "License :: OSI Approved :: MIT License",
 "Operating System :: OS Independent",
 ],
 packages=setuptools.find_packages(),
 python_requires=">=3.6",
)

3. Execute following commands:

python setup.py sdist
twine upload --repository testpypi dist/*

4. Import it from the test.pypi create and activate the venv

do

pip install --index-url https://test.pypi.org/simple/ --no-deps testDL-DeaL==0.0.9

write a test file: test.py:

from dlpk import b

and run it, it shows:

Traceback (most recent call last):
 File "H:\DLang\TEST\test.py", line 1, in <module>
 from dlpk import b
 File "H:\DLang\TEST\venv\lib\site-packages\dlpk\b.py", line 1, in <module>
 from a import A
ModuleNotFoundError: No module named 'a'

How does this error happen?

• metatoaster: As per the linked questions, the statement from a import A must be changed to either from dlpk.a import A (absolute import) or from .a import A (relative import).
• Dai: but it will report ModuleNotFoundError: No module named 'dlpk' for from dlpk.a import A and ImportError: attempted relative import with no known parent package for from .a import A
• metatoaster: That second error means you have not install the package into the currently active Python environment.
• Dai: I develope it under the global python environment. Does it mean that I should install the developing package to the global environment?
• metatoaster: The python you are running may be picking up a mix of the installed package and the developed package, possibly because of where your current working directory is. I cannot seem to replicate your issue. Try doing a import dlpk and then print(dlpk) to verify the thing you are trying to import is in fact the one you are expecting. You should also use a virtual environment while developing to constrain the issue (and make it easier for you to isolate the issue which you can do by creating a new one and optionally deleting the old one).