Option -a, --listenvs-all does not list environments defined with dict-like syntax

[volans-]

The option -a, --listenvs-all does not list environments defined implicitly inside the [testenv] section in the INI file through the dict-like syntax of commands.
It was introduced with #495 to fix #271.

Versions: tox 2.9.1 with Python 2.7.10 on macOS Sierra.

Repro setup:

[tox]
minversion = 1.6
skipsdist = true
envlist = default

[testenv]
whitelist_externals = echo
commands =
    default: echo "{envname}"
    extra: echo "{envname}"

Expected output:

$ tox -l
default
$ tox -a
default
extra

Current output:

$ tox -l
default
$ tox -a
default

It looks to me that the way the extra environment list is generated in https://github.com/tox-dev/tox/blob/master/tox/session.py#L652 takes account only of the INI sections in the tox.ini file. If I add a section [testenv:extra], then the extra environment is properly listed.

[volans-]

As a side note it would be nice to have the possibility to take advantage of the expanding syntax to define envlist but mark some of them as additional so that they do not run by default when executing tox alone.

Something like:

[tox]
envlist = {flake8,unit}{,-min,-extra}
mark_extra = min,extra

or

[tox]
envlist =  flake8,unit
extra_envlist =  {flake8,unit}-{min,extra}

But I'm going offtopic and towards a feature request, so I'll stop here.

[obestwalter]

Hi @volans- thanks for the report, the original request is a duplicate of #505 and as you can see there, it is not without it's thorns. Closing this one to keep the discussion there.

The second one also looks vaguely familiar. I think we have a similar request already, but I can't find it atm. Maybe you want to poke around a bit in the issues and check out the discussion there?

[volans-]

@obestwalter thanks for the quick reply, I searched a bit for similar issues before opening this one but didn't find the #505, sorry for the added noise. I'll look for the other one too.