Invalid wheel filename generated for namespace package

[wwuck]

I'm attempting to create and upload a package to TestPyPI with flit 3.5.1 using the new PEP420 feature

[build-system]
build-backend = 'flit_core.buildapi'
requires = ['flit_core >=3.5.1,<4']

[project]
authors = [{name = 'name', email = 'email'}]
classifiers = [
    'Development Status :: 1 - Planning',
    'Intended Audience :: Developers',
    'License :: OSI Approved :: MIT License',
    'Programming Language :: Python :: 3',
    'Programming Language :: Python :: 3.8',
    'Programming Language :: Python :: 3.9',
    'Programming Language :: Python :: 3.10',
    'Typing :: Typed',
]
dependencies = [
    'keyring>=23.3.0'
]
description = 'test package'
readme = 'README.rst'
version = '0.1.0-pre'
name = 'keyrings.testkeyringbackend'
requires-python = '>=3.8,<4'

I can build the package with flit --ini-file=pyproject.toml build and it generates both wheel and sdist files.

$ flit --ini-file=pyproject.toml build
Not generating setup.py in sdist (default changed)                                                                                                                                                                                                                                  I-flit
Recent versions of pip no longer need this generated file                                                                                                                                                                                                                           I-flit
Use --[no-]setup-py to suppress this message or add setup.py                                                                                                                                                                                                                        I-flit
Version number normalised: '0.1.0-pre' -> '0.1.0rc0' (see PEP 440)                                                                                                                                                                                                   W-flit_core.versionno
Version number normalised: '0.1.0-pre' -> '0.1.0rc0' (see PEP 440)                                                                                                                                                                                                   W-flit_core.versionno
Found 19 files tracked in git                                                                                                                                                                                                                                                 I-flit.sdist
Built sdist: dist/keyrings.testkeyringbackend-0.1.0rc0.tar.gz                                                                                                                                                                                                                       I-flit_core.sdist
Version number normalised: '0.1.0-pre' -> '0.1.0rc0' (see PEP 440)                                                                                                                                                                                                   W-flit_core.versionno
Copying package file(s) from /tmp/tmpw8v3wdc3/keyrings.testkeyringbackend-0.1.0rc0/src/keyrings/testkeyringbackend                                                                                                                                                                             I-flit_core.wheel
Writing metadata files                                                                                                                                                                                                                                                   I-flit_core.wheel
Writing the record of files                                                                                                                                                                                                                                              I-flit_core.wheel
Built wheel: dist/keyrings_testkeyringbackend-0.1.0rc0-py3-none-any.whl                                                                                                                                                                                                             I-flit_core.wheel

$ ls dist
keyrings_testkeyringbackend-0.1.0rc0-py3-none-any.whl  keyrings.testkeyringbackend-0.1.0rc0.tar.gz

When I try to upload with twine I get an error returned:

$ python3 -m twine upload --repository testpypi dist/*
Uploading distributions to https://test.pypi.org/legacy/
Uploading keyrings_testkeyringbackend-0.1.0rc0-py3-none-any.whl
100%|████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████| 23.3k/23.3k [00:02<00:00, 11.0kB/s]
Error during upload. Retry with the --verbose option for more details.
HTTPError: 400 Bad Request from https://test.pypi.org/legacy/
Start filename for 'keyrings.testkeyringbackend' with 'keyrings.testkeyringbackend'.

[takluyver]

It's actually a bug in the PyPI server code: pypi/warehouse#10030 . There's a PR already to fix it: pypi/warehouse#10072.

The wheel spec says that replacing . with _ is the correct thing to do there.

See also #442.

[wwuck]

Ahh thanks! Apologies for missing that previous bug. I’ll keep a watch in the warehouse bugs.

Thanks for implementing namespace support! Everything appears to be working fine so far.