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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"test_pickle/test_pickletools fail when running tests sequentially.","articleBody":"When running the test suite sequentially (as is done as part of the release process), an interaction between test_imp, test_importlib and subinterpreters is causing test_pickle and test_pickletools to fail. The easiest reproducer::\r\n\r\n```\r\n% ./python -m test test_imp test_importlib test_pickletools\r\n0:00:00 load avg: 0.22 Run tests sequentially\r\n0:00:00 load avg: 0.22 [1/3] test_imp\r\n0:00:00 load avg: 0.22 [2/3] test_importlib\r\n0:00:03 load avg: 0.22 [3/3] test_pickletools\r\ntest test_pickletools failed -- Traceback (most recent call last):\r\n  File \"Lib/test/pickletester.py\", line 1989, in test_builtin_types\r\n    s = self.dumps(t, proto)\r\n        ^^^^^^^^^^^^^^^^^^^^\r\n  File \"Lib/test/test_pickletools.py\", line 11, in dumps\r\n    return pickletools.optimize(pickle.dumps(arg, proto, **kwargs))\r\n                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\r\n_pickle.PicklingError: Can't pickle \u003cclass 'importlib._bootstrap.BuiltinImporter'\u003e: it's not the same object as importlib._bootstrap.BuiltinImporter\r\n\r\ntest_pickletools failed (1 error)\r\n\r\n== Tests result: FAILURE ==\r\n\r\n2 tests OK.\r\n\r\n1 test failed:\r\n    test_pickletools\r\n\r\nTotal duration: 4.2 sec\r\nTests result: FAILURE\r\n```\r\n \r\nThe failure happens in both test_pickle and test_pickletools (test_pickletools's traceback is more obvious), after _in the same process_ running both test_imp and either test_import or test_importlib. Disabling `test_imp.ImportTests.test_create_builtin_subinterp()` makes the tests pass. (This was happening before #102982 as well as after it, so I don't think it is involved here.)\r\n\r\nI expect this is an unintentional side-effect of the test, but this was _not_ happening in the 3.12.0a6 release, and as far as I can tell the relevant tests haven't changed since before a6. I'm delaying the 3.12.0a7 release until it's clear this isn't a fundamental problem with subinterpreters.\r\n\n\n\u003c!-- gh-linked-prs --\u003e\n### Linked PRs\n* gh-104186\n* gh-104226\n* gh-104345\n\u003c!-- /gh-linked-prs --\u003e\n","author":{"url":"https://github.com/Yhg1s","@type":"Person","name":"Yhg1s"},"datePublished":"2023-04-04T14:49:28.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":13},"url":"https://github.com/103247/cpython/issues/103247"}