Add a way to turn twine check warnings into errors

[Julian]

Hi!

twine check looks like beyond just failing if the output is invalid, it can output some warnings. E.g.:

readme run-test: commands[1] | /Users/julian/Development/jsonschema/.tox/readme/bin/python -m twine check '/Users/julian/Development/jsonschema/.tox/readme/tmp/dist/*'
Checking /Users/julian/Development/jsonschema/.tox/readme/tmp/dist/jsonschema-3.2.1.dev35+g9131e5cd.d20200124-py2.py3-none-any.whl: PASSED, with warnings
  warning: `long_description_content_type` missing.  defaulting to `text/x-rst`.
Checking /Users/julian/Development/jsonschema/.tox/readme/tmp/dist/jsonschema-3.2.1.dev35+g9131e5cd.d20200124.tar.gz: PASSED, with warnings
  warning: `long_description_content_type` missing.  defaulting to `text/x-rst`.

Not sure if there are other warnings it raises today -- twine check looks like it exits non-zero if an actual error occurs, but for nitpicky's sake, it seems like it'd be nice to be able to fail for warnings too.

(Apologies if there's some other way besides a CLI argument to do this and I missed it)

[di]

Sorry, it's not currently possible to turn these into errors.

In addition: these are warnings and not errors for a reason: twine check ensures that the distribution won't fail on upload to PyPI. The distribution is still valid, here, so twine check should pass without errors.

Can you give a bit more detail about why you want this to cause a failure?

[Julian]

The warnings seem like they're there to warn :) -- if there's literally nothing bad about them all good, but by having them it sounds like there's something to fix -- when twine check is run by a human the idea is presumably that you'd see them in the console, but when twine check isn't (e.g. in the above, where it runs in CI), no one would ever notice them to decide whether to fix or not (unless they fail the build, hence this kind of option). So if a warning was used to say, e.g., "some time in the future PyPI won't like this", you're (I'm) not going to notice until it actually breaks.

For analogy, e.g. sphinx-build takes a -W which turns warnings into errors (I assume for the same reasoning, though sphinx warnings are often borderline errors anyhow).

Does that make any more sense?

[bhrutledge]

That sounds reasonable to me; I'd probably do something like twine check --strict. @pypa/twine-maintainers what do y'all think?

[sigmavirus24]

I disagree @bhrutledge. Those warnings in particular are informational and don't require fixing. They're useful if and only if you're using markdown for the long description. Unlike sphinx the (I think only) warnings here are not guaranteed to be error worthy in what I'd guess is the majority use-case.

[Julian]

Cool, that's fine with me too if that's the case -- that means twine will guarantee that warnings emitted by it will never require action?

[di]

I think we can probably make that guarantee.

[Julian]

Sounds good thanks!

[ssbarnea]

Can we please reopen this? It makes no sense to not have a strict mode. I recently uploaded a package with empty description on pypi because during conversion from README.rst to README.md I forgot to update the setup.cfg file.

Yes, I did had a twine check as part of the release process, but missing a warning on the console is a very easy mistake to make.

[gaborbernat]

IMHO it's sane to have --strict here; while PyPi will accept the upload it's probably worth fixing these warnings if you care that your package looks good on PyPi.

[bhrutledge]

As the maintainer with the narrowest perspective, twine check --strict makes sense to me as a way to make uploading to PyPI friendlier. That said, I'm going to defer to the @pypa/twine-maintainers with a broader perspective.

[Julian]

(Re-opening, since I agree that that example seems to already not meet the "guarantee" above, but yeah obviously if there's still disagreement I won't feel bad if this is re-closed)

[bhrutledge]

twine check --strict has been released: https://pypi.org/project/twine/3.3.0/