Porting tox legacy ini to toml with factors

[shaib]

Hi,

I have a project with tox configuration for testing, with different versions of Python and Django. With the move from tox 3 to tox 4, I included the configuration as a legacy ini in my pyproject.toml , but I want to modernize it.

My current file includes:

[tool.tox]
legacy_tox_ini = """
[tox]
envlist = py39-django42, py{310,311,312}-django{42,50,51,52}, py313-django{51,52,main}
skipsdist = True

[testenv]
deps =
    flake8

    django42: Django>=4.2,<4.3
    django50: Django>=5.0,<5.1
    django51: Django>=5.1,<5.2
    django52: Django>=5.2,<5.3
    djangomain: git+https://github.com/django/django.git@main#egg=django
    psycopg2-binary
    dj-database-url>=2.3.0,<3.0

# ...
"""

Is there a sensible way to reproduce this with native TOML? All I could find required giving up all the shorthands -- e.g. if an envlist like this can still be defined at all, it seems to require also that each of the combinations of Python and Django be explicitly given its own TOML table.

Is there a way to do this without massive duplication?

[gaborbernat]

Historically, the INI format was created first, and TOML was added in 2024. The TOML format generally is more robust, however is less powerful and more verbose. You should use TOML unless you need some of the more advanced features that TOML does not support (such as conditional factors, generative environments to name a few – however, PRs to add support for these in TOML is welcome).

https://tox.wiki/en/stable/config.html

[shaib]

Thanks for the clarification.

[the-citto]

hi
having the same wish, I found this discussion - and finally confirmation: thanks for preventing me from getting insane!

edit: had to roll back to tox.ini as even all in legacy_tox_ini in pyproject.toml wasn't working for me - perhaps something to do with tox-uv

I can't remember what other tool didn't like mixing legacy and not legacy, but at first try it seems that legacy_tox_ini plays nice with the other pyproject.toml entries

I ended up with this (here with some additional TOML things just as example)

[tool.tox]
requires = [
    "tox>=4",
    "tox-uv",
]
isolated_build = true
legacy_tox_ini = """
[tox]
envlist = {linux,windows}-{py313,py314}-{checkers}
"""

it seems sensible and it seems to work well

I was wondering if a TOML array of arrays could do? surely without the brace-patterns

annoying note: some AI slop really insists that envlist = ["{linux,windows}-{py313,py314}-{checkers}"] is a valid TOML entry, which instead is not even considered by tox with no errors