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3185bb5827
The recently merged 5e9189d6d1 now allows
temporary slices to be allocated on the C stack, which is much better than
allocating them on the GC heap.
Unfortunately there are cases where the C-allocated slice can escape and be
retained as an object, which leads to crashes (because that object points
to the C stack which now has other values on it).
The fix here is to add a new `MP_TYPE_FLAG_SUBSCR_ALLOWS_STACK_SLICE`.
Native types should set this flag if their subscr method is guaranteed not
to hold on to a reference of the slice object.
Fixes issue #17733 (see also #17723).
Signed-off-by: Damien George <damien@micropython.org>
24 lines
675 B
Python
24 lines
675 B
Python
# Test that the slice-on-stack optimisation does not break various uses of slice
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# (see MP_TYPE_FLAG_SUBSCR_ALLOWS_STACK_SLICE type option).
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#
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# Note: this test has a corresponding .py.exp file because hashing slice objects
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# was not allowed in CPython until 3.12.
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try:
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from collections import OrderedDict
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except ImportError:
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print("SKIP")
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raise SystemExit
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# Attempt to index with a slice, error should contain the slice (failed key).
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try:
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dict()[:]
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except KeyError as e:
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print("KeyError", e.args)
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# Put a slice and another object into an OrderedDict, and retrieve them.
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x = OrderedDict()
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x[:"a"] = 1
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x["b"] = 2
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print(list(x.keys()), list(x.values()))
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