test_xpickle failure, something about builtins.sentinel

[smontanaro]

Bug report

Bug description:

test_xpickle is failing on MacOS for me (main branch). It seems there's a new sentinel name in builtins. I see a bunch tracebacks like this:

ERROR: test_builtin_types (test.test_xpickle.CPicklePython315Compat.test_builtin_types) (name='sentinel', proto=5)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Users/skip/src/python/cpython/Lib/test/pickletester.py", line 3300, in test_builtin_types
    s = self.dumps(t, proto)
  File "/Users/skip/src/python/cpython/Lib/test/test_xpickle.py", line 190, in dumps
    return self.send_to_worker(python, data)
           ~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^
  File "/Users/skip/src/python/cpython/Lib/test/test_xpickle.py", line 172, in send_to_worker
    raise exception
AttributeError: module 'builtins' has no attribute 'sentinel'

I suspect it's expecting – but not finding – sentinel in the builtins of older versions. The test finds versions of the interpreter on my machine from 3.7 onwards. FWIW, it passes on my Ubuntu laptop (many fewer versions of the interpreter there, however). Seems odd that it would be MacOS-specific though.

CPython versions tested on:

CPython main branch

Operating systems tested on:

macOS

[smontanaro]

I just verified that test_xpickle works on the 3.15 branch. (main reports that it is 3.16.0a0.)

[JelleZijlstra]

I suspect this might be because you have a local 3.15 installation that predates the addition of builtins.sentinel?

[StanFromIreland]

The test passes on the Buildbot: https://buildbot.python.org/#/workers/123

[smontanaro]

I suspect this might be because you have a local 3.15 installation that predates the addition of builtins.sentinel?

Thanks, indeed I do (now did). The date of that installation was March 1. I just wiped it all out and the test now passes.