[Triage] potential breakage in v25 when using gevent worker_class

[markjm]

Thanks for maintaining that great project! Below is my first bug report here so please let me know if anything is unclear!

Type

Bug Report

Description

It seems that v25 has changed some import ordering which can break gevent-patch-using projects. Specifically, concurrent.futures now seems to be imported before any use-defined code runs. This is relevant for gevent-based projects, because concurrent.futures holds references to certain threading threads, which can not be patched after import time.

In our project, we have identified that this missed patching causes issues with other packages which use concurrent.futures. Specifically boto3 s3 operations can start hanging. We fortunately have a hard startup fail to catch this otherwise-difficult-to-notice patching issue, which is why we caught this

        for module in ["concurent.futures"]:
            if module in sys.modules:
                raise RuntimeError(
                    f"'{module}' was detected before gevent patch. gevent patch must be imported before any other modules that use {module}"
                )

Steps to Reproduce (for bugs)

I have created a single-file repro with steps in:

https://gist.github.com/markjm/9f724364619c519892e8111fe6520ca6

This demonstrated that some non-patched threads linger in concurrent.futures. I am not 100% sure that the example one i used (_global_shutdown_lock) is the one which causes issues at runtime, but i think it demonstrated the problem

Configuration

gunicorn echo:app -c echo.py

Logs / Error Output

v24 output:

=== LOCK COMPARISON TABLE ===
Check                          | BEFORE PATCH                   | AFTER PATCH
------------------------------------------------------------------------------------------------
Type                           | <class 'gevent.thread.LockType'> | <class 'gevent.thread.LockType'>
Module                         | gevent.thread                  | gevent.thread
Is GeventLockType?             | True                           | True
Is _thread.LockType?           | True                           | True

v25 output:

=== LOCK COMPARISON TABLE ===
Check                          | BEFORE PATCH                   | AFTER PATCH
------------------------------------------------------------------------------------------------
Type                           | <class '_thread.lock'>         | <class 'gevent.thread.LockType'>
Module                         | _thread                        | gevent.thread
Is GeventLockType?             | False                          | True
Is _thread.LockType?           | False                          | True

Gunicorn Version

gunicorn (version 25.0.0)

Python Version

Python 3.12.10

Worker Class

gevent

Operating System

Ubuntu 24.04

Additional Context

No response

Checklist

• I have searched existing discussions and issues for duplicates
• I have checked the documentation and FAQ

[benoitc]

I created #3482 for it. Please test the PR #3483 associated.