Adopt bdist_wheel from wheel project

[agronholm]

Currently the setuptools.command.dist_info command relies on the bdist_wheel code to create a .dist-info directory. But since wheel has no public API, this is dangerous as that code could go away in the next release. The dist_info command should be natively implemented in setuptools instead, without the conversion from .egg-info.

[jaraco]

This effort is going to be a lot of work. The egg_info command has a lot of cruft and deprecated functionality... and the contract between egg_info and dist_info is largely implicit.

On the other hand, it looks like the main thing that dist_info needs is the metadata, which is written in the same format as with egg_info, so probably the distutils write_pkg_info can be leveraged directly. We'll take it bit-by-bit.

[agronholm]

I'm starting my summer vacation today. Hopefully I can contribute to this effort.

[mattip]

As per pypa/wheel#262, maybe an easier path would be to move bdist_wheel here and use an as-yet-not-created official API from wheel.

[agronholm]

That would be ideal.

[merwok]

That sounds better than calling distutils’ write_pkg_info, as it does not handle the most recent metadata versions with email-style separation of headers and long description.

[abravalheri]

pypa/packaging#383 and pypa/packaging#498 might be relevant here.

[jaraco]

Steps to integrate bdist_wheel:

• copy implementation of wheel/bdist_wheel to setuptools/commands/bdist_wheel
• define distutils.command for bdist_wheel in setuptools
• vendor wheel as setuptools/_vendor/wheel*
• update build backend to no longer require wheel
• prevent distutils.command from wheel package from being loaded (in

  setuptools/setuptools/dist.py

  Line 713 in 7208628

  eps = metadata.entry_points(group='distutils.commands', name=command)

  and maybe others); remove after a long term

[adang1345]

Question: If I'm looking to fix a bug in the bdist_wheel command, where should the fix go from now on? Should it go to setuptools/command/bdist_wheel.py, setuptools/_vendor/wheel/bdist_wheel.py, the https://github.com/pypa/wheel project, or multiple of these?

[agronholm]

I think the first step is to report the bug. If the bug relates specifically to bdist_wheel and not the other vendored wheel code, then likely it should only be fixed in setuptools.