This turns out to be more involved than I anticipated it to be 😇

I think to be able to get rid of using virtualenv to install wheel, pyproject-api needs to be update to not require wheel. Which would be in line with the pyproject.toml specs:

[build-system]
# Minimum requirements for the build system to execute.
requires = ["setuptools"]

Build tools are expected to use the example configuration file above as their default semantics when a pyproject.toml file is not present.

I think it might be this line that's causing issues: https://github.com/tox-dev/pyproject-api/blob/46dc443b1a33599fb76f869bd911fd4827eafb0d/src/pyproject_api/_frontend.py#L179

This turns out to be more involved than I anticipated it to be 😇

I think to be able to get rid of using virtualenv to install wheel, pyproject-api needs to be update to not require wheel. Which would be in line with the pyproject.toml specs:

[build-system]
# Minimum requirements for the build system to execute.
requires = ["setuptools"]

Build tools are expected to use the example configuration file above as their default semantics when a pyproject.toml file is not present.

I think it might be this line that's causing issues: tox-dev/pyproject-api@46dc443/src/pyproject_api/_frontend.py#L179

You're correct here.

https://github.com/tox-dev/pyproject-api/releases/tag/1.9.1

With pyproject-api 1.9.1, this works and fixes the issue for me.