deprecation notice for 3.7 modifies global state (user warning filters) as import side-effect

[artgromov]

It is impossible to filter Python37DeprecationWarning after PR #1371.

Custom libraries should not configure warning filters, because it is user project's global state. Most of the times you cannot modify import order and insert new warning filters after your library modifies them.

Environment details

• OS: Ubuntu 22.04.3 LTS linux 5.15.0-89-generic
• Python version: 3.7.17
• pip version: 23.3.1
• google-auth version: 2.24.0

Steps to reproduce

1. install google-auth into your python3.7 project
2. configure filterwarning rule ignore::DeprecationWarning in pytest.ini
3. use google.auth or google.oauth2 somewhere in your project
4. run pytest
5. get Python37DeprecationWarning that you cannot filter

[parthea]

Hi @artgromov!

Thanks for reporting this issue. It will be fixed in #1428.

Here is the pytest.ini that I used for testing

[pytest]
filterwarnings =
    # treat all warnings as errors
    error
    ignore:After January 1, 2024, new releases of this library will drop support for Python 3.7:DeprecationWarning