Implement copyslot by youknowone · Pull Request #6505 · RustPython/RustPython

youknowone

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📝 Walkthrough

Walkthrough

This PR refactors protocol access patterns across the VM, replacing MRO-based slot lookups with direct class slot access. It introduces new unchecked accessors for sequences and mappings, restructures PyNumber/PySequence/PyMapping with slot-based designs, removes cached protocol methods from heap types, and adds slot inheritance helpers to simplify type initialization.

Changes

Cohort / File(s)	Summary
Core Protocol Restructuring `crates/vm/src/protocol/number.rs`, `crates/vm/src/protocol/sequence.rs`, `crates/vm/src/protocol/mapping.rs`	Introduced `PySequenceSlots` and `PyMappingSlots` structures for atomic slot storage. Renamed `to_number()` to `number()` and restructured `PyNumber` from tuple-newtype to named-field struct. Updated `PySequence` and `PyMapping` to use slot-based dispatch instead of static method references. Added `sequence_unchecked()`, `try_sequence()`, `mapping_unchecked()`, and `try_mapping()` accessors on `PyObject`.
Type System and Slot Management `crates/vm/src/types/slot.rs`, `crates/vm/src/builtins/type.rs`, `crates/vm/src/class.rs`	Changed `as_sequence` and `as_mapping` fields in `PyTypeSlots` from `PointerSlot` to `PySequenceSlots`/`PyMappingSlots`. Removed `sequence_methods` and `mapping_methods` fields from `HeapTypeExt`. Removed `mro_find_map` method and added slot inheritance helpers (`inherit_slots`, `inherit_readonly_slots`, `inherit_number_slots`, etc.). Updated type initialization to inherit slots from base types. Added wrappers for `__str__` and `__bool__` enforcement.
Object Protocol Implementation `crates/vm/src/protocol/object.rs`, `crates/vm/src/object/core.rs`	Replaced MRO-based slot lookups with direct `obj.class().slots.X.load()` access patterns across attribute access, item operations, comparisons, repr, hash, and length operations. Updated descriptor lookups to use direct slot access instead of MRO traversal.
VM Operations and Execution `crates/vm/src/vm/vm_ops.rs`, `crates/vm/src/vm/method.rs`, `crates/vm/src/vm/vm_object.rs`, `crates/vm/src/frame.rs`	Replaced MRO-based lookups for number operation slots, descriptor getters, and attribute access with direct slot retrieval. Updated arithmetic and comparison operator paths to use direct slot access. Simplified method resolution in ExecutingFrame.
Protocol Implementations `crates/vm/src/protocol/callable.rs`, `crates/vm/src/protocol/iter.rs`, `crates/vm/src/protocol/buffer.rs`	Changed call and iterator slot lookups from MRO-based search to direct class slot access. Updated `PyCallable::new`, `PyIter::check`, and buffer protocol to use `obj.class().slots.X.load()` directly.
Function Protocol `crates/vm/src/function/protocol.rs`	Removed `methods` field from `ArgMapping` struct. Changed constructor from `with_methods(obj, methods)` to `new(obj)`. Updated `mapping()` method to use `self.obj.mapping_unchecked()`. Simplified `TryFromObject` implementation for `ArgMapping` by removing methods validation step.
Builtin Types `crates/vm/src/builtins/bool.rs`, `crates/vm/src/builtins/classmethod.rs`, `crates/vm/src/builtins/dict.rs`, `crates/vm/src/builtins/iter.rs`, `crates/vm/src/builtins/list.rs`, `crates/vm/src/builtins/mappingproxy.rs`, `crates/vm/src/builtins/weakproxy.rs`	Updated containment and sequence access patterns to use `sequence_unchecked()` instead of `to_sequence()`. Removed `PySequenceMethods` caching in `PySequenceIterator`. Updated `PyClassMethod` pyclass attribute to include `Initializer`. Changed mapping proxy construction to use `ArgMapping::new()` and direct slot validation.
Standard Library `crates/stdlib/src/sqlite.rs`, `crates/vm/src/stdlib/builtins.rs`, `crates/vm/src/stdlib/ctypes/structure.rs`, `crates/vm/src/stdlib/ctypes/union.rs`, `crates/vm/src/stdlib/typing.rs`	Updated numeric access from `to_number()` to `number()` in SQLite collation. Changed eval globals mapping check to use `mapping_unchecked().check()`. Replaced MRO-based descriptor lookups in ctypes with direct slot access. Added `init()` function for typing module initialization.
Module Exports `crates/vm/src/protocol/mod.rs`, `crates/vm/src/types/structseq.rs`, `crates/vm/src/types/zoo.rs`	Added `PyMappingSlots` and `PySequenceSlots` to public protocol exports. Updated struct sequence slot initialization to use `copy_from()` for direct slot population. Added typing module initialization to TypeZoo.

Estimated code review effort

🎯 4 (Complex) | ⏱️ ~50 minutes

Possibly related PRs

iter with slot-wrapper #6488: Modifies iterator slot-wrapper machinery and class slot handling in parallel with changes to iter initialization and PySequenceIterator refactoring.
disallow __new__, __init__ #6446: Updates pyclass initialization with Constructor/Initializer traits, aligning with the classmethod attribute changes and slot-based initialization patterns in this PR.
ctypes overhaul #6450: Modifies ctypes implementation (PyCStructType, PyCUnionType) descriptor handling, which overlaps with the descriptor slot lookup refactoring in this PR.

Suggested reviewers

ShaharNaveh
arihant2math
coolreader18

🐰 Protocol slots now shimmer bright,
Direct access replaces MRO's flight,
Unchecked pathways swift and clean,
Type slots wired, a cleaner scene,
The rabbit hops through refactored light!

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📜 Recent review details

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📥 Commits

Reviewing files that changed from the base of the PR and between 7eb0fe4 and c83101f.

⛔ Files ignored due to path filters (1)

Lib/test/test_typing.py is excluded by !Lib/**

📒 Files selected for processing (32)

crates/stdlib/src/sqlite.rs
crates/vm/src/builtins/bool.rs
crates/vm/src/builtins/classmethod.rs
crates/vm/src/builtins/dict.rs
crates/vm/src/builtins/iter.rs
crates/vm/src/builtins/list.rs
crates/vm/src/builtins/mappingproxy.rs
crates/vm/src/builtins/object.rs
crates/vm/src/builtins/type.rs
crates/vm/src/builtins/weakproxy.rs
crates/vm/src/class.rs
crates/vm/src/frame.rs
crates/vm/src/function/protocol.rs
crates/vm/src/object/core.rs
crates/vm/src/protocol/buffer.rs
crates/vm/src/protocol/callable.rs
crates/vm/src/protocol/iter.rs
crates/vm/src/protocol/mapping.rs
crates/vm/src/protocol/mod.rs
crates/vm/src/protocol/number.rs
crates/vm/src/protocol/object.rs
crates/vm/src/protocol/sequence.rs
crates/vm/src/stdlib/builtins.rs
crates/vm/src/stdlib/ctypes/structure.rs
crates/vm/src/stdlib/ctypes/union.rs
crates/vm/src/stdlib/typing.rs
crates/vm/src/types/slot.rs
crates/vm/src/types/structseq.rs
crates/vm/src/types/zoo.rs
crates/vm/src/vm/method.rs
crates/vm/src/vm/vm_object.rs
crates/vm/src/vm/vm_ops.rs

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