I have a bad news for you Eric: I'm able again to reproduce the crash at commit f13c5c8b9401a9dc19e95d8b420ee100ac022208.


vstinner@freebsd$ ./python -m test --matchfile=bisect5 test_multiprocessing_spawn --fail-env-changed -F
Run tests sequentially
0:00:00 load avg: 0.69 [  1] test_multiprocessing_spawn
0:00:06 load avg: 0.80 [  2] test_multiprocessing_spawn
0:00:12 load avg: 1.19 [  3] test_multiprocessing_spawn
...
0:01:55 load avg: 1.48 [ 21] test_multiprocessing_spawn
0:02:01 load avg: 1.53 [ 22] test_multiprocessing_spawn
0:02:08 load avg: 1.29 [ 23] test_multiprocessing_spawn
0:02:17 load avg: 1.51 [ 24] test_multiprocessing_spawn
0:02:27 load avg: 2.27 [ 25] test_multiprocessing_spawn
0:02:38 load avg: 3.14 [ 26] test_multiprocessing_spawn
0:02:48 load avg: 3.51 [ 27] test_multiprocessing_spawn
Warning -- files was modified by test_multiprocessing_spawn
  Before: []
  After:  ['python.core'] 
test_multiprocessing_spawn failed (env changed)

== Tests result: ENV CHANGED ==

All 26 tests OK.

1 test altered the execution environment:
    test_multiprocessing_spawn

Total duration: 2 min 59 sec
Tests result: ENV CHANGED


Note: Sorry for not testing before, after one long week, I didn't succeed to catch up with my very long list of unread emails.

I don't know what should be done. Revert? I don't have the bandwidth to investigate this crash.