Clean up pip exclusion.

[freakboy3742]

#1196 added exclusions for pip 23.1; however, due to the way that tox auto-updates pip to the most-recent version, an explicit configuration was needed to avoid using pip 23.1 in practice. That configuration is no longer required, and hard-pinning an old version of pip isn't desirable.

Fixes #1195.

PR Checklist:

• All new features have been tested
• All new features have been documented
• I have read the CONTRIBUTING.md file
• I will abide by the code of conduct

[freakboy3742]

This isn't passing CI right now; as soon as there is an updated version of pip that resolves pypa/pip#11982, it should pass. I've submitted this as a PR so that we don't forget the cleanup that will be required once that happens.

[rmartin16]

hmm...pip 23.1.1 released....still failing...

[freakboy3742]

Is it possible something (e.g., a tox environment) is being cached?

[rmartin16]

No...I found it, though.

virtualenv does some sneaky stuff apparently. It embeds a copy of pip....right now, that embedded version is 23.1. By default, this is where virtualenv will source the version of pip to install in to virtual environments that are created. Presumably, an upcoming version of virtualenv will update this and allow CI to properly run.

That said, virtualenv supports a flag to always download the latest version of pip (as well as setuptools and wheel).

This finally worked for me:

diff --git a/tox.ini b/tox.ini
index d1c27bb7..06e25d1e 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,3 +1,6 @@
+[pkgenv]
+download = True
+
 # The leading comma generates the "py" environment.
 [testenv:py{,38,39,310,311,312}]
 passenv =
@@ -5,6 +8,7 @@ passenv =
     LOCALAPPDATA
 extras =
     dev
+download = True
 commands =
     python -m coverage run -m pytest -vv {posargs}

[freakboy3742]

Ugh... so... the problem is caused by the fact that it downloads the latest version of pip... and the only way to fix it is to force the download of the latest version of pip. 🤯

[rmartin16]

well...tox downloads the latest virtualenv which is 20.22.0 and that version includes pip 23.1....and that's what's installed when the virtual env is created; so, later runs of this pip then fail. Using download=True tells virtualenv to just fetch the latest pip instead of using its embedded version.

[freakboy3742]

So - what was causing the error previously then? Did we just luck out and have Virtualenv push out a new version that pinned 23.1 as soon as it was available, but they haven't pushed out an update that pins 23.1.1?

[rmartin16]

Yeah, I think so. pip==23.1 was released April 15 and virtualenv==20.21.1 and virtualenv==20.22.0 were released on April 19.