Add list support to c-api by bschoenmaeckers · Pull Request #7944 · RustPython/RustPython

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📥 Commits

Reviewing files that changed from the base of the PR and between fe2571d and 5032743.

📒 Files selected for processing (2)

crates/capi/src/lib.rs
crates/capi/src/listobject.rs

📝 Walkthrough

Walkthrough

Adds a public listobject module and implements C-API list functions (New, Size, GetItemRef, SetItem, Append, Insert, Reverse) that run inside the VM, downcast to RustPython lists, perform bounds-checked reads/mutations, and return Python index errors on invalid indices.

Changes

C-API List Object Support

Layer / File(s)	Summary
Module declaration and list helpers `crates/capi/src/lib.rs`, `crates/capi/src/listobject.rs`	Module `listobject` is publicly exported; `PyList_Check`/`PyList_CheckExact` helpers are defined.
List construction and query operations `crates/capi/src/listobject.rs`	`PyList_New` creates a list with reserved capacity; `PyList_Size` returns length; `PyList_GetItemRef` retrieves items by index with bounds checking and VM index errors.
List mutation operations `crates/capi/src/listobject.rs`	`PyList_SetItem` assigns items (rejects negative indices; includes capacity-based fill special-case), `PyList_Append` appends, `PyList_Insert` inserts with normalized/clamped index handling, and `PyList_Reverse` reverses in place; functions return `c_int` status and use VM-created errors on failure.
Unit tests (disabled) `crates/capi/src/listobject.rs`	Disabled `#[cfg(false)]` PyO3 test module covering creation, replacement, bounds errors, append, insert, and reverse.

Sequence Diagram

sequenceDiagram
  participant CCaller as C Caller
  participant PyList_CAPI as PyList C-API
  participant VM as VM
  participant PyList as PyList
  CCaller->>PyList_CAPI: call PyList_New(size) / PyList_* APIs
  PyList_CAPI->>VM: with_vm (enter VM context)
  VM->>PyList: allocate or downcast to PyList and operate on Vec
  PyList->>VM: return results/errors
  VM->>PyList_CAPI: propagate return value / error
  PyList_CAPI->>CCaller: return pointer or status

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

RustPython/RustPython#7871: Introduced the define_py_check! macro used for PyList_Check/PyList_CheckExact.

Suggested reviewers

ShaharNaveh
youknowone

Poem

🐇 I nibbled bytes and stitched a list so neat,
New, Size, Get, Set — each hop a small feat,
Append and Insert, then Reverse on repeat,
A tiny rabbit patch where C and VM greet,
Soft paws pushing items in tidy beat.

🚥 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 'Add list support to c-api' directly and clearly summarizes the main change: adding C-API functions for list operations to the RustPython project.
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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✨ Finishing Touches

🧪 Generate unit tests (beta)

Create PR with unit tests

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