Importing urllib3.exceptions.SubjectAltNameWarning fails under 2.0.x

[cthart]

Subject

from urllib3.exceptions import SubjectAltNameWarning

fails with

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: cannot import name 'SubjectAltNameWarning' from 'urllib3.exceptions' (/home/colin/venv/lib/python3.8/site-packages/urllib3/exceptions.py)

under urllib 2.0.2 (also under 2.0.1 and 2.0.0)

Can this exception no longer occur? There is no mention of it in the Changelog or Release descriptions. In addition, searching the repository commits for SubjectAltNameWarning doesn't yield any recent changes at all, so I'm stumped why this exception is no longer available, even when it is available under urllib3 1.26.15 with all other installed libraries the same.

Environment

Describe your environment.
At least, paste here the output of:

OS Linux-6.2.6-1-pve-x86_64-with-glibc2.29 (Ubuntu 20.04.6 LTS)
Python 3.8.10
urllib3 2.0.2

Steps to Reproduce

As above

Expected Behavior

Import should succeed, as it does under urllib3 1.26.15

Actual Behavior

Import fails with exception as above

[pquentin]

Hello! And thank you for your report. Sorry that urllib3 2.0 broke your code. The reason the warning disappeared is that in urllib3 2.0 this is no longer a warning but an error: #2113

Can you please share what is your use case for importing the warning?

[cthart]

I'm trying to fix one of the libraries I'm using: https://github.com/hbldh/pybankid/blob/master/bankid/__init__.py

[cthart]

Pull request submitted for that library. hbldh/pybankid#48
This code works for with test and production certificates, so I'm hopeful this patch or a variant of it will be applied.
Closing this issue.

[pquentin]

Thanks! Until I see a proper use case for declaring a fake SubjectAltNameWarning in 2.0, I'd like to avoid doing it: if you want your code to work at all under urllib3 2.0, this warning should not fire in 1.26.x. So I think the proper fix is always going to be to fix that warning and then remove the filter.

Also note that if you have outdated TLS certificates in your test suite, https://github.com/python-trio/trustme is your friend. :)

[cthart]

Yes, sorry if my last message was a bit cryptic: I'm not expecting a change to requests, but hopeful that just removing checks for this particular warning in the pybankid library will work for everyone. It works fine for me.