Hi!

While rebuilding the python related packages against the Python 3.15
version we found that gcovr fails to build from source:
https://debusine.debian.net/debian/r-python-python3.15/artifact/4855550/

 From the log, the error seems to be:
    dh_auto_build -i -O--buildsystem=pybuild
I: pybuild plugin_pyproject:142: Building wheel for python3.14 with
"build" module
I: pybuild base:385: python3.14 -m build --skip-dependency-check
--no-isolation --wheel --outdir 
/build/reproducible-path/gcovr-8.6/.pybuild/cpython3_3.14
* Building wheel...
Successfully built gcovr-8.6-py3-none-any.whl
I: pybuild plugin_pyproject:168: Unpacking wheel built for python3.14
with "installer" module
    debian/rules override_dh_auto_test
make[1]: Entering directory '/build/reproducible-path/gcovr-8.6'
py3versions: no X-Python3-Version in control file, using supported
versions
set -e; for py in python3.15 python3.14; do \
	PYTHONPATH=src $py -m gcovr --version; \
done
/bin/sh: 2: python3.15: not found

It looks like the problem is that gcovr build-depends on python3, and
should instead build-depend on python3-all, so that all supported
versions get installed.

Setting the severity to important for now. Once Python 3.15 is released
and later added to python3-defaults, this bug will become release
critical.