``test_type_cache`` fails with ``--forever`` argument

[Eclips4]

Bug report

Bug description:

Trace:

./python.exe -m test -q test_type_cache --forever
Using random seed: 2064316463
0:00:00 load avg: 2.54 Run tests sequentially
test test_type_cache failed -- Traceback (most recent call last):
 File "/Users/admin/Projects/cpython/Lib/test/test_type_cache.py", line 132, in test_class_load_attr_specialization_static_type
 self._assign_and_check_valid_version(str)
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^
 File "/Users/admin/Projects/cpython/Lib/test/test_type_cache.py", line 90, in _assign_and_check_valid_version
 self.assertNotEqual(type_get_version(user_type), 0)
 ~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 0 == 0


== Tests result: FAILURE ==

1 test failed:
 test_type_cache

Total duration: 50 ms
Total tests: run=14 failures=1
Total test files: run=2 failed=1
Result: FAILURE

CPython versions tested on:

CPython main branch

Operating systems tested on:

macOS

Linked PRs

• gh-113937 Fix failures in type cache tests due to re-running #113953

[Eclips4]

Seems to be introduced in #113558. This PR should be backported to 3.11 and 3.12 (but not backported yet), that's why I'm adding 3.11 & 3.12 labels.

Theoretically it may not be reproducible on 3.11 (maybe some deep internal changes were made) I'll check it when backports will be done.

[Eclips4]

Another error also occurs if we run this test using -R 3:3:

FAIL: test_property_load_attr_specialization_user_type (test.test_type_cache.TypeCacheWithSpecializationTests.test_property_load_attr_specialization_user_type)
----------------------------------------------------------------------
Traceback (most recent call last):
 File "/Users/admin/Projects/cpython/Lib/test/test_type_cache.py", line 172, in test_property_load_attr_specialization_user_type
 self._check_specialization(load_x_1, G(), "LOAD_ATTR", should_specialize=True)
 ~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 File "/Users/admin/Projects/cpython/Lib/test/test_type_cache.py", line 101, in _check_specialization
 self.assertIn(opname, self._all_opnames(func))
 ~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 'LOAD_ATTR' not found in {'LOAD_FAST', 'RETURN_CONST', 'POP_TOP', 'RESUME_CHECK', 'LOAD_ATTR_PROPERTY'}

[Fidget-Spinner]

Thanks for the report. I'll take a look.

[lazorchakp]

Sorry for this - I certainly introduced it. The first issue should be resolvable by skipping tests if we run out of version tags (like what was done in the preexisting test_tp_version_tag_unique). I'm not sure what could be causing the second, though. @Fidget-Spinner if you'd like another set of eyes on this, lmk

[Fidget-Spinner]

@lazorchakp if you'd like to submit a PR to fix it I would be happy to review it as well! For the second case, it's possible that the specialization has not reverted yet. In CPython, code objects are shared across functions (so every time you create a new function, it reuses the same code object, you can dis.dis a closure to see what I mean). So the specialization from a previous iteration could stick around for abit until it de-specializes by running the loop a few times. Because of that, I think it's fine to remove that line.

[lazorchakp]

Oh that's interesting! I should be able to get a PR open pretty quickly