Ref leaks introduced by _io isolation (gh-101948) #104510
Description
Tried on current main.
./python -m test -R 3:3 test_nntplib
0:00:00 load avg: 2.49 Run tests sequentially
0:00:00 load avg: 2.49 [1/1] test_nntplib
beginning 6 repetitions
123456
......
test_nntplib leaked [1222, 1220, 1222] references, sum=3664
test_nntplib leaked [828, 827, 829] memory blocks, sum=2484
test_nntplib failed (reference leak)
== Tests result: FAILURE ==
1 test failed:
test_nntplib
Total duration: 640 ms
Tests result: FAILUREOS: WSL Ubuntu 20.04 & Windows 10
UPD:
Leaked tests:
test_nntplib
test_gzip
test_httpservers
test_xmlrpc
test_tarfile