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Kwak Byoung Min
3492c1cef1
Constraint: Python-level sentinel equality can re-enter the same callable iterator while internal iterator state is protected by a non-reentrant lock. Rejected: Holding the callable iterator status lock across sentinel equality | user-defined __eq__ can call next() on the same iterator and deadlock. Confidence: high Scope-risk: moderate Tested: pre-commit run --all-files; cargo test --workspace --exclude rustpython_wasm --exclude rustpython-venvlauncher; cargo build --release --features sqlite; pytest -v in extra_tests; cargo run --quiet -- extra_tests/snippets/protocol_iternext.py; cargo check -p rustpython-vm; cargo clippy -p rustpython-vm --all-targets -- -D warnings; git diff --check Not-tested: push/PR creation Assisted-by: Codex:gpt-5.5
46 lines
1005 B
Python
46 lines
1005 B
Python
ls = [1, 2, 3]
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i = iter(ls)
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assert i.__next__() == 1
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assert i.__next__() == 2
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assert next(i) == 3
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assert next(i, "w00t") == "w00t"
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s = "你好"
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i = iter(s)
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i.__setstate__(1)
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assert i.__next__() == "好"
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assert i.__reduce__()[2] == 2
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# Regression test for re-entrant callable iterator sentinel equality.
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# Equality can execute Python code that calls back into the same iterator.
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class ReenterEq:
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entered = False
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it = None
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def __eq__(self, other):
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if not self.entered:
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self.entered = True
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try:
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next(self.it)
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except StopIteration:
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pass
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else:
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raise AssertionError("inner next should stop at the sentinel")
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return True
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value = ReenterEq()
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sentinel = object()
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callable_it = iter(lambda: value, sentinel)
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value.it = callable_it
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try:
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next(callable_it)
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except StopIteration:
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pass
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else:
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raise AssertionError("outer next should stop at the sentinel")
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assert value.entered
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