long_description_content_type flag in setup.py is ignored. IE #4079 not fixed.

[hlovatt]

The long_description_content_type flag in setup.py is still ignored despite original bug #4079 now closed and marked as fixed.

For my setup.py of:

long_description=read_text('README.md'),
long_description_content_type='text/markdown',

I get the following errors:

`long_description` has syntax errors in markup and would not be rendered on PyPI.
line 112: Warning: Inline literal start-string without end-string.
warning: `long_description_content_type` missing. defaulting to `text/x-rst`.

The syntax error is not correct, the README renders on everything I have tried!

Therefore suspect that long_description_content_type error, which isn't missing, is the problem!

All files at:

https://github.com/hlovatt/statmach

[di]

Hi, can you attach the built distributions you're attempting to upload?

[ewjoachim]

TL;DR, most probably:

• The root cause: Newlines in the description field produce a malformed PKG-INFO pypa/setuptools#1390
• A similar problem: long_description_content_type flag in setup.py seems to (still) be ignored on upload. #9315
• Your fix:

Replace license=read_text('LICENSE') with license="MIT License"

---

Hello,

I've tried your files at hlovatt/statmach. More precisely, I've tried the following command:

python setup.py sdist && twine check --strict dist/*

As you'll notice, this command doesn't involve PyPI: it builds the package, and then checks it using Twine (nothing is sent).

Even if the current state of your master branch replaces the long description:

long_description=f'See {statmach.__repository__} for detailed description.\n',  # read_text('README.md'),

it still seems to fail with:

Checking dist/statmach-1.0.8.tar.gz: FAILED, due to warnings
  warning: `long_description_content_type` missing. defaulting to `text/x-rst`.

Replacing the line with:

long_description=read_text('README.md'),

doesn't change the check output, so it seems the problem is elsewhere.

The problem seems to be that you're loading the entire license file in the license field rather than just a single-line string, such as MIT License. Multiline strings create problems with setuptools as seen in #9315.

The fix is to only let long_description contain newlines. This is not #4079.
Of course, if pypa/setuptools#1390 gets resolve, this would also fix your issue.

I cannot guarantee that your problem is this, and that there isn't any other problem hiding behind but I can say that having multiple lines in the license field as in the project you linked will produce the error you mentionned.

[hlovatt]

Many thanks for the help. Multiline license text is indeed the problem.