[BUG] autodiscovery for single-module layout causes build_wheel(".") to produce an empty wheel

[mgorny]

setuptools version

65.5.1

Python version

3.11.0

OS

Gentoo Linux

Additional environment information

No response

Description

When the package is using a flat distribution layout for a single Python module with autodiscovery, the build-backend produces an empty wheel if wheel_dir is .. It seems to work correctly if a subdirectory is used as wheel_dir.

I've noticed this with bitstring package.

Expected behavior

Correct package or an explicit error.

How to Reproduce

cat > pyproject.toml <<EOF
[build-system]
requires = ["setuptools>=61"]
build-backend = "setuptools.build_meta"

[project]
name = "test"
version = "1"
EOF

> foo.py
python -c 'import setuptools.build_meta; setuptools.build_meta.build_wheel(".")'

Output

running bdist_wheel
running build
running build_py
running egg_info
creating test.egg-info
writing test.egg-info/PKG-INFO
writing dependency_links to test.egg-info/dependency_links.txt
writing top-level names to test.egg-info/top_level.txt
writing manifest file 'test.egg-info/SOURCES.txt'
listing git files failed - pretending there aren't any
reading manifest file 'test.egg-info/SOURCES.txt'
writing manifest file 'test.egg-info/SOURCES.txt'
installing to build/bdist.linux-x86_64/wheel
running install
running install_lib
warning: install_lib: 'build/lib' does not exist -- no Python modules to install

running install_egg_info
Copying test.egg-info to build/bdist.linux-x86_64/wheel/test-1-py3.11.egg-info
running install_scripts
creating build/bdist.linux-x86_64/wheel/test-1.dist-info/WHEEL
creating '/tmp/test/tmpygf6hdpg/test-1-py3-none-any.whl' and adding 'build/bdist.linux-x86_64/wheel' to it
adding 'test-1.dist-info/METADATA'
adding 'test-1.dist-info/WHEEL'
adding 'test-1.dist-info/top_level.txt'
adding 'test-1.dist-info/RECORD'
removing build/bdist.linux-x86_64/wheel

$ unzip -l test-1-py3-none-any.whl 
Archive:  test-1-py3-none-any.whl
  Length      Date    Time    Name
---------  ---------- -----   ----
       45  11-18-2022 17:32   test-1.dist-info/METADATA
       92  11-18-2022 17:32   test-1.dist-info/WHEEL
       12  11-18-2022 17:32   test-1.dist-info/top_level.txt
      268  11-18-2022 17:32   test-1.dist-info/RECORD
---------                     -------
      417                     4 files

[mgorny]

Thanks!

[abravalheri]

Thank you very much for reporting @mgorny.

[mgorny]

I've confirmed that it builds the wheel for bitstring correctly now.