Memory leak when calling cothread.Spawn on Python>=3.11

[ptsOSL]

To reproduce, install cothread>=2.19 on Python>=3.11. Run this test:

import cothread

def test():
    print("hi")
 
while True:
    cothread.Spawn(test)
    cothread.Yield()

And you should see your memory usage rapidly increase.

This is most likely caused by the change c32a5a8 which does not clean up after the cothread has finished.

I got the error with:

python
Python 3.11.11 (main, Dec 9 2024, 15:32:27) [GCC 8.5.0 20210514 (Red Hat 8.5.0-22)] on linux
Type "help", "copyright", "credits" or "license" for more information.

pip list
Package Version

---

cothread 2.20.0
dls_slow_feedbacks 1.1.0+4.g72b71bc.dirty
epicscorelibs 7.0.7.99.1.2a1
epicsdbbuilder 1.5
numpy 2.2.5
pip 22.3.1
pvxslibs 1.3.3
pytac 0.5.0
PyYAML 6.0.2
scipy 1.15.3
setuptools 65.5.1
setuptools_dso 2.12.2
softioc 4.6.1