Add more list functions to the c-api#8045

bschoenmaeckers

Summary by CodeRabbit

New Features
- Expanded list manipulation capabilities with four new C-API functions enabling list-to-tuple conversion, slice retrieval, slice modification, and list sorting.
Tests
- Reorganized and enhanced test suite for list operations.

coderabbitai

📝 Walkthrough

Walkthrough

This PR extends RustPython's CPython compatibility layer by adding four new list C-API functions: PyList_AsTuple, PyList_GetSlice, PyList_SetSlice, and PyList_Sort. The implementation uses RustPython's VM internals and includes updates to test coverage and test naming conventions.

Changes

List C-API Extensions

Layer / File(s)	Summary
New list C-API functions with imports `crates/capi/src/listobject.rs`	Updated imports add `AsObject` and slice utilities (`SaturatedSlice`, slice traits). Four new `extern "C"` FFI functions dispatch through the RustPython VM to implement list-to-tuple conversion, slice retrieval with saturated bounds, slice modification/deletion (including null-pointer deletion), and list sorting via the sort method.
Test coverage and refactoring `crates/capi/src/listobject.rs`	Existing test functions renamed by removing the `test_` prefix. Test module extended with comprehensive coverage for tuple conversion, slice get/set operations, list reversal, and sorting assertions under `#[cfg(false)]`.

Sequence Diagram(s)

No sequence diagram generated. This PR introduces FFI function implementations within a single module without multi-component sequential flows that would benefit from visualization.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

Possibly related PRs

RustPython/RustPython#7944: Adds foundational PyList_New, PyList_SetItem, PyList_Append, PyList_Insert, and PyList_Reverse C-API functions to the same listobject.rs module, sharing the VM dispatch pattern used by this PR's new functions.
RustPython/RustPython#8019: Introduces PySlice_* C-API support and SaturatedSlice utilities that the new PyList_GetSlice and PyList_SetSlice functions depend upon.
RustPython/RustPython#7907: Adds tuple C-API support in tupleobject.rs that aligns with this PR's new PyList_AsTuple conversion function.

Suggested reviewers

ShaharNaveh
youknowone

Poem

🐰 List magic unfolds, four new spells are cast,
Slice, sort, tuple—a feast unsurpassed!
RustPython's embrace grows ever more wide,
C-API friends hop along for the ride! 🐇✨

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely summarizes the main change: adding new list-related functions to the C-API, which aligns directly with the changeset introducing PyList_AsTuple, PyList_GetSlice, PyList_SetSlice, and PyList_Sort.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@crates/capi/src/listobject.rs`:
- Around line 160-164: PyList_Sort currently downcasts to PyList and uses
vm.call_method(list.as_object(), "sort", ()) which performs normal Python-level
dispatch and can run overridden user code; change it to invoke the builtin list
sort implementation directly (not via instance dispatch). Specifically, replace
vm.call_method(...) in PyList_Sort with a direct call to the internal list
sorting routine (the in-place sorter for PyList) or call the "sort" function
bound to the exact built-in list type rather than the instance (e.g., resolve
the attribute on vm.ctx.types.list_type and invoke that bound function with the
list as self, or call PyList's internal sort method such as the library's
sort_inplace routine), ensuring no instance-level __dict__/subclass override can
run. Use the symbols PyList_Sort, PyList, and avoid vm.call_method to implement
this change.

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ℹ️ Review info

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Run ID: 5c374d9b-913d-4252-8864-62b444550774

📥 Commits

Reviewing files that changed from the base of the PR and between 51c97b9 and 073cd03.

📒 Files selected for processing (1)

crates/capi/src/listobject.rs

Add more list functions to the c-api

073cd03

coderabbitai Bot reviewed Jun 4, 2026

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youknowone approved these changes Jun 10, 2026

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bschoenmaeckers deleted the c-api-more-list branch June 10, 2026 07:09

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Add more list functions to the c-api#8045