pybuild pyproject.toml problem

[Ole Streicher <olebole@debian.org>]

Hi,

I have a package

https://salsa.debian.org/debian-astro-team/asdf-standard

that changed its build process to pyproject.toml. As hinted by pybuild,
I added pybuild-plugin-pyproject to the build dependencies; however it
still does not build properly. The build fails with the following
output:

-------------------------------8<-----------------------------------
* Building wheel...
Successfully built UNKNOWN-1.0.3-py3-none-any.whl
I: pybuild plugin_pyproject:118: Unpacking wheel built for python3.10 with "installer" module
E: pybuild pybuild:369: build: plugin pyproject failed with: UNKNOWN wheel found: UNKNOWN-1.0.3-py3-none-any.whl. Does pyproject.toml specify a build-backend?
dh_auto_build: error: pybuild --build -i python{version} -p 3.10 returned exit code 13
make: *** [debian/rules:5: binary] Error 25
-------------------------------8<-----------------------------------

which I do not understand. The build backend specified in pyproject.toml is

build-backend = "setuptools.build_meta"

What goes wrong here?

Full build log:

https://salsa.debian.org/debian-astro-team/asdf-standard/-/jobs/3095942

Cheers

Ole