[jseop-lim]

Description

Fixes #1255

PyObjectSetItem and PyObjectDelItem converted an index key only for types with sq_ass_item, so on a type with sequence slots but no sq_ass_item (tuple, str, bytes, range, frozenset, a plain class) they raised TypeError without calling __index__. CPython's PyObject_SetItem and PyObject_DelItem convert the key whenever the type has tp_as_sequence, so an error from __index__, or IndexError for an oversized int, comes first (abstract.c#L237-L252, #L271-L286).

AS-IS

>>> operator.setitem((), RaisingIndex(), 0)   # RaisingIndex.__index__ raises ZeroDivisionError
TypeError: 'tuple(EmptySequenceStorage[])' object does not support item assignment
>>> del ''[RaisingIndex()]
TypeError: '' object does not support item deletion
>>> operator.setitem('', 2**100, 0)
TypeError: '' object does not support item assignment

TO-BE

>>> operator.setitem((), RaisingIndex(), 0)
ZeroDivisionError
>>> del ''[RaisingIndex()]
ZeroDivisionError
>>> operator.setitem('', 2**100, 0)
IndexError: cannot fit 'int' into an index-sized integer

(matching CPython)

Changes

• Add a doSequenceNoAssItem specialization to PyObjectSetItemGeneric and PyObjectDelItemGeneric for mp_ass_subscript == null, sq_ass_item == null and has_as_sequence(). It converts an index key with PyNumberIndexNode, raises IndexError when the result does not fit in 64 bits, and otherwise raises the existing TypeError. The converted value is not used, so the check follows CPython's 64-bit Py_ssize_t rather than GraalPy's 32-bit index size, and a key such as 2**40 keeps raising TypeError.
• Add test_setitem_delitem_convert_index_before_type_error to tests/test_operator.py.

Testing

mx python-jvm on darwin-aarch64. tests/test_operator.py passes (4 tests), and the new test fails on the unpatched build. The tagged lib-python suites test_operator, test_index, test_list, test_tuple, test_bytes, test_genericalias, test_types, test_userlist, test_dict, test_array and test_deque pass. Setting and deleting with four keys (a raising __index__, 2**100, 0 and "k") on 34 builtin and user-defined objects now gives the same exception class as CPython 3.13.14, as do the boundary keys 2**31, 2**40, 2**63 - 1, 2**63, -2**63 and -2**63 - 1, apart from itertools.count, which has no sequence slots in GraalPy. Types without sequence slots, such as types.GenericAlias and types.UnionType, still raise TypeError.