Switch to using virtualenv's rewrite branch

[pradyunsg]

Let's see how our CI / tests setup reacts to newer virtualenv.

I'm pretty sure our isolation logic will be completely broken now.

[pradyunsg]

Ah shucks. I forgot that @gaborbernat is on the setuptools_scm band-wagon.

[RonnyPfannschmidt]

i believe using yesterdays 20.0.0.b2 should do fine

[pradyunsg]

i believe using yesterdays 20.0.0.b2 should do fine

Well, I'm pretty sure it won't because our test suite does horrible things.

[BrownTruck]

Hello!

I am an automated bot and I have noticed that this pull request is not currently able to be merged. If you are able to either merge the master branch into this pull request or rebase this pull request against master then it will be eligible for code review and hopefully merging!

[pradyunsg]

Good bot.

[frenzymadness]

Virtualenv 20.0.20 is available and it would be very nice if pip can use it for tests. We are going to update virtualenv in Fedora soon and the update will break tests of pip.

[pfmoore]

I believe the issue is that our test harness uses virtualenv APIs that were removed in the rewrite, so we need to change to remove our reliance on them. PRs are of course welcome to address this :-)

[pradyunsg]

#7718 is a more up-to-date PR for this. I won't be able to pick this back up anytime soon. If this is a blocker for others, I welcome PRs to fix this incompatibility! I know there's a whole bunch of nuance here and a couple of assumptions in pip's test suite that get broken, but they all seem fixable to me. :)

[gaborbernat]

@pradyunsg where did this land? Is this done then?

[uranusjr]

This did not land, and AFAIK all efforts (including mine) have stalled. For me, this requires too much effort I don’t have in to re-implement the whole thing containing ten years worth of logic :(

[pradyunsg]

Yep to what @uranusjr said.

This needs someone with enough understanding of both pip and virtualenv, to spend a decent amount of time to figure out "what used to be" -> "what should be now", and whether there's stuff in the test suite that can be directly dropped.

There's a reason I had asked around for help with this back when the rewrite was happening. I'm not familiar with the edge cases of virtualenv, and it's internals. 🙃

[gaborbernat]

I am happy to answer questions about virtualenv but unlikely at the moment that I'll start working on pip.