python / python/cpython

test_track_literals depends on a garbage collection

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#155,728 7 comments 0 reactions 1 assignee View on GitHub

@sergey-miryanov is already working on this.

Since Aug 13, 2026.

3.14 3.15 3.16 interpreter-core tests type-bug
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Python
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Description

Bug report

_not_tracked_instantly() requires the tuple to be untracked without a collection. This holds for tuples created at run time, but tuple constants are created tracked and are only untracked by _PyTuple_MaybeUntrack(), which is called only from the collector.

$ ./python -c "import gc; print(gc.is_tracked((1,)))"
True

So test_track_literals passes only if a collection happens between importing the module and running the test. Under regrtest it does not:

$ ./python -m test test_tuple -m test_track_literals
AssertionError: True is not false : (1,)

while ./python -m unittest test.test_tuple.TupleTest.test_track_literals passes.

Untracking tuple constants when the code object is created would let the test keep the stronger check.

Linked PRs
  • gh-156419
  • gh-156423

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