symlinks not supported by pip / setup.py?

[asciidoc3]

• Pip version: 18.0
• Python version: 3.6
• Operating system: debian sid

Hi, I searched and tried for (a lot of) hours to get symlinks in my package asciidoc3 (see alpha here https://pypi.org/project/asciidoc3/ and about 50(!) attempts https://test.pypi.org/project/asciidoc3).
I failed; it's frustrating. 'include_package_data=True' / MANIFEST.in doesn't work: 'data_files contains unexpected objects'. Say, we have

myprogram.py
myprogram.conf
images ---
       image1.png
       image2.png
       ...
other_data ---
       other_data1.txt
       other_data2.txt
       images --> ./images  # <-- ?

What can I do to "install" the symlink 'images --> ./images' in dir 'other_data' in ~/.local/lib/python3.5/site-packages/myprogram/other_data?
The 'workaround' described here https://stackoverflow.com/questions/20288711/post-install-script-with-python-setuptools
(using 'class my_install(install_data)' and 'cmdclass={'install_data': my_install}' ...) didn't work either. And here another link, which does not help me: #3500

Is there a way to include symlinks?

[uranusjr]

I don’t think packaging symlinks is a good idea in general, since it is extremely likely to break on Windows. It would also be difficult to support symlinks inside a wheel, since Python’s zipfile module does not support archiving symlinks at the current time.

[cjerdonek]

See also this very recent comment by @waveform80: #5848 (comment)

[chrahunt]

Given that the packaging attempts for asciidoc3 3.0.2.post* were all sdists formatted as tar.gz, it should not be an issue to have a symlink included in the sdist itself or to get setup.py to generate a symlink when it is executed. If this is a problem with that phase then I would suggest IRC, StackOverflow, or (if it looks like something is wrong) the setuptools issue tracker.

For pip's handling of that sdist there are two routes:

1. legacy install that invokes setup.py directly - this should work but again depends on the behavior of setuptools - this is the one that would apply for asciidoc3 if wheel is not installed since it does not include a pyproject.toml
2. building a wheel and then installing it - pip is responsible for the wheel extraction and currently this will fail - addressing this one way or another is covered by Symlink (and other) handling of archives #5919.

[chrahunt]

Hello. For getting the symlinks into an sdist in the first place I would check the setuptools issue tracker and mailing list, sending a question to the mailing list if there are no results. Given the pip-specific changes to support these use cases are in #5919 I will close this issue and we can track the activity there. Thank you for reporting!