``test_import`` crashes with a ``--forever`` option

[Eclips4]

Crash report

Bug description:

./python.exe -m test -v test_import -m test_check_state_first --forever
== CPython 3.14.0a0 (heads/main:5d04cc50e5, May 26 2024, 21:33:31) [Clang 15.0.0 (clang-1500.3.9.4)]
== macOS-14.5-arm64-arm-64bit-Mach-O little-endian
== Python build: debug
== cwd: /Users/admin/Projects/cpython/build/test_python_worker_94626æ
== CPU count: 8
== encodings: locale=UTF-8 FS=utf-8
== resources: all test resources are disabled, use -u option to unskip tests

Using random seed: 4127756675
0:00:00 load avg: 4.71 Run tests sequentially
0:00:00 load avg: 4.71 [  1] test_import
test_check_state_first (test.test_import.SinglephaseInitTests.test_check_state_first) ... ok

----------------------------------------------------------------------
Ran 1 test in 0.001s

OK
0:00:00 load avg: 4.71 [  2] test_import
test_check_state_first (test.test_import.SinglephaseInitTests.test_check_state_first) ... Assertion failed: (_testsinglephase_with_reinit_check_cache_first.m_base.m_index == 0), function PyInit__testsinglephase_with_reinit_check_cache_first, file _testsinglephase.c, line 714.
Fatal Python error: Aborted

Current thread 0x00000001f61d0c00 (most recent call first):
  File "<frozen importlib._bootstrap>", line 488 in _call_with_frames_removed
  File "<frozen importlib._bootstrap_external>", line 1316 in create_module
  File "<frozen importlib._bootstrap>", line 813 in module_from_spec
  File "<frozen importlib._bootstrap>", line 921 in _load_unlocked
  File "<frozen importlib._bootstrap>", line 966 in _load
  File "/Users/admin/Projects/cpython/Lib/test/test_import/__init__.py", line 2495 in _load_dynamic
  File "/Users/admin/Projects/cpython/Lib/test/test_import/__init__.py", line 2894 in test_check_state_first
  File "/Users/admin/Projects/cpython/Lib/unittest/case.py", line 606 in _callTestMethod
  File "/Users/admin/Projects/cpython/Lib/unittest/case.py", line 651 in run
  File "/Users/admin/Projects/cpython/Lib/unittest/case.py", line 707 in __call__
  File "/Users/admin/Projects/cpython/Lib/unittest/suite.py", line 122 in run
  File "/Users/admin/Projects/cpython/Lib/unittest/suite.py", line 84 in __call__
  File "/Users/admin/Projects/cpython/Lib/unittest/suite.py", line 122 in run
  File "/Users/admin/Projects/cpython/Lib/unittest/suite.py", line 84 in __call__
  File "/Users/admin/Projects/cpython/Lib/unittest/runner.py", line 240 in run
  File "/Users/admin/Projects/cpython/Lib/test/libregrtest/single.py", line 57 in _run_suite
  File "/Users/admin/Projects/cpython/Lib/test/libregrtest/single.py", line 37 in run_unittest
  File "/Users/admin/Projects/cpython/Lib/test/libregrtest/single.py", line 135 in test_func
  File "/Users/admin/Projects/cpython/Lib/test/libregrtest/single.py", line 91 in regrtest_runner
  File "/Users/admin/Projects/cpython/Lib/test/libregrtest/single.py", line 138 in _load_run_test
  File "/Users/admin/Projects/cpython/Lib/test/libregrtest/single.py", line 181 in _runtest_env_changed_exc
  File "/Users/admin/Projects/cpython/Lib/test/libregrtest/single.py", line 281 in _runtest
  File "/Users/admin/Projects/cpython/Lib/test/libregrtest/single.py", line 310 in run_single_test
  File "/Users/admin/Projects/cpython/Lib/test/libregrtest/main.py", line 355 in run_test
  File "/Users/admin/Projects/cpython/Lib/test/libregrtest/main.py", line 389 in run_tests_sequentially
  File "/Users/admin/Projects/cpython/Lib/test/libregrtest/main.py", line 533 in _run_tests
  File "/Users/admin/Projects/cpython/Lib/test/libregrtest/main.py", line 568 in run_tests
  File "/Users/admin/Projects/cpython/Lib/test/libregrtest/main.py", line 731 in main
  File "/Users/admin/Projects/cpython/Lib/test/libregrtest/main.py", line 739 in main
  File "/Users/admin/Projects/cpython/Lib/test/__main__.py", line 2 in <module>
  File "/Users/admin/Projects/cpython/Lib/runpy.py", line 88 in _run_code
  File "/Users/admin/Projects/cpython/Lib/runpy.py", line 198 in _run_module_as_main

Extension modules: _testinternalcapi, _testmultiphase (total: 2)
zsh: abort      ./python.exe -m test -v test_import -m test_check_state_first --forever

CPython versions tested on:

CPython main branch

Operating systems tested on:

macOS

Linked PRs

• gh-119584: Fix test_import Failed Assertion #119623
• [3.13] gh-119584: Fix test_import Failed Assertion (gh-119623) #119633

[Eclips4]

Bisected to 0c5ebe1
cc @ericsnowcurrently

[Eclips4]

I'm guess this test (and two other tests which are similar) is cannot be run multiple times:

cpython/Modules/_testsinglephase.c

Lines 692 to 701 in 5482a93

	PyMODINIT_FUNC
	PyInit__testsinglephase_check_cache_first(void)
	{
	assert(_testsinglephase_check_cache_first.m_base.m_index == 0);
	PyObject *mod = PyState_FindModule(&_testsinglephase_check_cache_first);
	if (mod != NULL) {
	return Py_NewRef(mod);
	}
	return PyModule_Create(&_testsinglephase_check_cache_first);
	}

Firstly we check if m_index == 0, which means that our module is not in the cache. Then, we try to find this module using the PyState_FindModule which relies on the m_index field, and works only when m_index >= 0. These two steps seem weird for me.
1)We can just mark the test_check_state_first with a no_rerun decorator, due to the reason that this test is to check whether initializing the module with different m_size works.
2) Change the assert to m_index >= 0 instead of m_index == 0

[ericsnowcurrently]

I'll have a fix up shortly.