Actionable comments posted: 0

🧹 Nitpick comments (2)

extra_tests/snippets/builtin_type.py (1)

280-291: Consider adding an assertion to verify the class was actually changed.

The test verifies that slot_a.__class__ = SlotA2 doesn't raise, but doesn't verify the assignment actually took effect.

🔎 Proposed addition

 slot_a = SlotA()
 slot_a.__class__ = SlotA2  # Should work
+assert type(slot_a) is SlotA2
+assert slot_a.__class__ is SlotA2

crates/vm/src/builtins/object.rs (1)

529-538: Itemsize check is missing—already noted in TODO comments.

The layout compatibility check covers basicsize, slot names/count, and HAS_DICT differences but omits itemsize comparison. This gap is already documented in TODO comments elsewhere in the codebase (crates/vm/src/builtins/object.rs and crates/vm/src/builtins/type.rs). Variable-size object handling is relevant for RustPython's buffer protocol and variable-size types, though the scope of user-defined variable-size classes may differ from CPython. Weakref layout differences are also not checked; consider whether RustPython's weakref handling requires explicit layout validation for class assignment.

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🧬 Code graph analysis (1) extra_tests/snippets/builtin_type.py (1)

extra_tests/snippets/testutils.py (1)

• assert_raises (5-12)

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🔇 Additional comments (4)

crates/vm/src/builtins/object.rs (2)

500-502: Good refactoring to cache current_cls.

Caching instance.class() ensures consistency throughout the method, avoiding potential issues if the class were to change between checks (though unlikely in practice).

---

510-528: The positional slot comparison using zip is overly restrictive and does not match CPython's actual behavior.

CPython allows class reassignment even when slots are in different orders (e.g., ("x", "y") and ("y", "x")), but the current implementation rejects such cases because it compares slots positionally. This should either be fixed to allow reordered slots (like CPython does) or have a clear documented reason for the stricter validation.

Likely an incorrect or invalid review comment.

extra_tests/snippets/builtin_type.py (2)

243-260: Good coverage for dict vs slots layout mismatch.

This test correctly verifies that assigning a class with __slots__ to an instance of a class with __dict__ raises a TypeError with the appropriate message. The use of assert_raises context manager with message validation is good practice.

---

263-277: Nice edge case: same slot count, different slot names.

This test is valuable because it validates that the implementation compares slot names, not just slot counts. This catches a potential bug where only len() comparison might have been used.