[jseop-lim]

Description

Fixes #1226

The __reversed__ methods of dict, dict_keys, dict_items and dict_values wrapped the reverse storage iterator with the forward factories, so the result was a dict_keyiterator, dict_valueiterator or dict_itemiterator. The PDictReverse*Iterator types are still defined and registered with IteratorBuiltins, but nothing has created them since afc1f12 removed their factories. CPython builds all four from the PyDictRevIter*_Type types (dictobject.c#L4494).

AS-IS

>>> d = {1: 'a'}
>>> type(reversed(d)), type(reversed(d.values())), type(reversed(d.items()))
(<class 'dict_keyiterator'>, <class 'dict_valueiterator'>, <class 'dict_itemiterator'>)
>>> type(reversed(d)) is type(iter(d))
True

TO-BE

>>> type(reversed(d)), type(reversed(d.values())), type(reversed(d.items()))
(<class 'dict_reversekeyiterator'>, <class 'dict_reversevalueiterator'>, <class 'dict_reverseitemiterator'>)
>>> type(reversed(d)) is type(iter(d))
False

(matching CPython)

Changes

• Restore PFactory.createDictReverse{Key,Item,Value}Iterator in their pre-afc1f123e6 shape, building the same Java iterator objects with the reverse types.
• Call them from DictBuiltins.ReversedNode, DictViewBuiltins.ReversedNode (keys and items) and DictValuesBuiltins.ReversedNode.
• Add test_reversed_iterator_types to tests/test_dict.py.

The reverse types need no disallowInstantiation(): PythonBuiltinClassType already sets it for a builtin type without tp_new whose base is object, so calling one raises TypeError as in CPython, which the new test checks.

Testing

mx python-jvm on linux-aarch64, then mx graalpytest test_dict.py test_ordered_dict.py test_iterator.py test_map_strategies.py (110 passed). test.test_dict, test.test_dictviews and test.test_ordered_dict from lib-python give the same per-test results as on master. The new test fails on the unpatched build. For all four reversed() calls, the type name, iteration order, __length_hint__, __reduce__, pickling and instantiation now match CPython 3.12.13.