Incremental GC does not collect garbage as soon as expected

Bug report

Bug description:

This was found by @Yhg1s . If you run tests with this command:

./python -m test --randseed=3169227856 --no-randomize --single-process test_pyclbr test_trace test_pdb test_iter test_ordered_dict test_urllib2_localnet test_array test_generated_cases test_typing test_fnmatch test_tools test_descr test___all__ test_xml_dom_xmlbuilder test_nturl2path test_hmac test_pickle test_android test_ipaddress test_modulefinder test_interpreters test_zoneinfo test_runpy test_sqlite3 test_bdb test_zipfile test_crossinterp test_pulldom test_pkgutil test_re test_dbm_sqlite3 test_venv test_pyrepl test_xml_etree_c test_gc

The test_gc unit test fails with:

  File "/home/thomas/python/python/main/Lib/contextlib.py", line 85, in inner
    return func(*args, **kwds)
  File "/home/thomas/python/python/main/Lib/test/test_gc.py", line 1573, in test_bug1055820d
    self.fail("gc didn't happen after 50000 iterations")
    ~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: gc didn't happen after 50000 iterations

Reverting GH-140262 seems to fix this. It is possible this is related to GH-141890 as well.

CPython versions tested on:

CPython main branch

Operating systems tested on:

Linux

Linked PRs

• gh-142001

test/test_gc.py、特に test_bug1055820d から始め、報告に記載されたコマンドを使って失敗を再現してください。GH-140262 をリバートした場合の動作と比較し、GH-141890 との関連の可能性を調査してください。50,000 回の反復後にガベージコレクションが失敗したとテストが報告しなくなれば完了です。