No tty / color support on Windows

[schlamar]

Issue

Color output in Windows from tools does not work as expected.

Expected output:

Actual output within tox:

This should have been fixed by @masenf in #2711 So maybe there was a regression since then.

Environment

Provide at least:

• OS: Windows
• pip list of the host Python where tox is installed:

Package       Version
------------- -------
cachetools    5.2.0
chardet       5.1.0
colorama      0.4.6
distlib       0.3.6
filelock      3.9.0
packaging     22.0
pip           22.3.1
platformdirs  2.6.2
pluggy        1.0.0
pyproject_api 1.4.0
setuptools    65.6.3
tomli         2.0.1
tox           4.2.1
virtualenv    20.17.1
wheel         0.38.4

Minimal example

If possible, provide a minimal reproducer for the issue:

[testenv]
deps = pytest
commands =
    python -c 'import sys; print("sys.stdout.isatty(): %s" % sys.stdout.isatty()); print("to stdout, should be colorless\n"); print("sys.stderr.isatty(): %s" % sys.stderr.isatty());        print("to stderr, should be red?\n", file=sys.stderr)'
    pytest {posargs}

test_test.py

def test():
    assert False

[schlamar]

Maybe the implementation from @masenf does not support Windows, but in this case merging #2816 was wrong.

[masenf]

On my windows Python 3.11 installation, the termios stdlib module is not available, and thus #2711 would not actually have an effect on windows: https://github.com/tox-dev/tox/pull/2711/files#diff-7db0796890e2c916e1d687a28bb382fe2c3a359eef2080621f3e5b3b8cca4927R293-R295

I wouldn't consider this a regression from #2711, but it is a regression from tox 3, which didn't do output capturing of the main commands and thus didn't have to deal with tty allocation in order to get colorized and interactive output.

We should leave this issue open to fix tty allocation on windows platform.

[schlamar]

In this case this is probably a duplicate of #2337

However, you should revert #2816 or better clarify in the documentation that this is still an issue on Windows.

[masenf]

Adding TTY support for windows (#2337) is far from trivial because even though there is a new ConPTY interface in Win10, it does not return a handle that can be passed to subprocess. Likely would need an entirely separate implementation.

I think the doc change in #2816 should be reverted and changed to mention that the regression only affects windows (and probably reference 2337 there, for users that want to find out why)

[gaborbernat]

@adamchainz can you add a PR with this amendment?