Support for Generative Env Lists in extras

[adam-grant-hendry]

I attempted to create a generative environment list under the extras key in my tox.ini to only install pyqt6 in the pyqt6 environment and pyside6 in the pyside6 environment respectively:

[testenv]
description = Run tests
runner = uv-venv-lock-runner
extras =
    pyqt6:
        tests
        pyqt6
    pyside6:
        tests
        pyside6
depends =
    py3{9,10,11,12}-{pyqt6,pyside6}: clean
    coverage: py3{9,10,11,12}-{pyqt6,pyside6}
setenv =
    ; See: https://github.com/tox-dev/tox/issues/1550
    PYTHONIOENCODING=utf-8
    COVERAGE_FILE=.coverage.{envname}
    ; See https://github.com/pytest-dev/pytest-qt/issues/437
    pyqt6:
        D:PYTEST_QT_API=pyqt6
        D:QT_API=pyqt6
    pyside6:
        D:PYTEST_QT_API=pyside6
        D:QT_API=pyside6
commands =
    coverage run -m pytest {posargs:tests}

However, it seems all extras get installed. For example, in my py39-pyqt6 environment.

My package uses qtpy under the hood, so it is important only one Qt backend be loaded in each environment to ensure the right tests are being run.

Does tox-uv support generative lists in this manner?

[adam-grant-hendry]

Since this might not be supported by tox extras itself, I simply switched my tox.ini to this for the time-being:

[testenv]
description = Run tests
runner = uv-venv-lock-runner
depends =
    py3{9,10,11,12}-{pyqt6,pyside6}: clean
    coverage: py3{9,10,11,12}-{pyqt6,pyside6}
allowlist_externals =
    coverage
commands =
    coverage run -m pytest {posargs:tests}

[testenv:py3{9,10,11,12}-pyqt6]
extras = tests,pyqt6
setenv =
    ; See: https://github.com/tox-dev/tox/issues/1550
    PYTHONIOENCODING=utf-8
    COVERAGE_FILE=.coverage.{envname}
    ; See https://github.com/pytest-dev/pytest-qt/issues/437
    D:PYTEST_QT_API=pyqt6
    D:QT_API=pyqt6

[testenv:py3{9,10,11,12}-pyside6]
extras = tests,pyside6
setenv =
    ; See: https://github.com/tox-dev/tox/issues/1550
    PYTHONIOENCODING=utf-8
    COVERAGE_FILE=.coverage.{envname}
    ; See https://github.com/pytest-dev/pytest-qt/issues/437
    D:PYTEST_QT_API=pyside6
    D:QT_API=pyside6