Sorry, forget that.

I completely messed myself up, as missed that this command is not executed from the venv you assume, but already from prepared venv by tox based of the minversion. As I had minversion = 4.0 - it installed 4.0 and then `tox config` worked.

3.28 does not actually have it, in fact, so it's 4.0 thing.

пт, 6 мар. 2026 г. в 16:45, Dmitriy Rabotyagov <noonedeadpunk@gmail.com>:

I was not able to find the exact version where it was added, but I just checked, and tox==3.28.0 already has it.

пт, 6 мар. 2026 г. в 16:41, Jeremy Stanley <fungi@yuggoth.org>:
On 2026-03-06 10:57:39 +0100 (+0100), Dmitriy Rabotyagov wrote:
>I _think_ we are having an issue in zuul job, which just uses old tox
>syntax for dumping the configuration.
>So potentially, smth like [1] should be fixing the issue while preserving
>the expected behavior.
>
>As `tox config -e py3` is dumping the config as expected, while `tox
>--showconfig -e py3` is crashing.
>
>[1] https://review.opendev.org/c/zuul/zuul-jobs/+/979136
[...]

Has anyone yet looked into how far back the newer syntax is
supported? We still have projects testing with tox v3 on some
branches, so would need that to remain working as well.
--
Jeremy Stanley