Add object protocol methods to c-api by bschoenmaeckers · Pull Request #7882 · RustPython/RustPython · GitHub

Summary by CodeRabbit

New Features
- Extended the C API surface with new object operations for getting, setting, and deleting items, and added subclass/instance checks—improving compatibility with C extensions and interoperability with code relying on these fundamental object behaviors.
- Exposed the new API group at crate/module level so it’s available to C consumers.

No actionable comments were generated in the recent review. 🎉

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📥 Commits

Reviewing files that changed from the base of the PR and between 8cc3821 and 4357f78.

📒 Files selected for processing (2)

crates/capi/src/abstract_.rs
crates/capi/src/lib.rs

🚧 Files skipped from review as they are similar to previous changes (1)

crates/capi/src/abstract_.rs

📝 Walkthrough

Walkthrough

A new FFI module adds five C-ABI extern functions that wrap PyObject operations (GetItem, SetItem, DelItem, IsSubclass, IsInstance), converting raw *mut PyObject pointers to Rust references and executing the underlying methods inside with_vm.

Changes

PyObject FFI Wrappers

Layer / File(s)	Summary
Module declaration and imports crates/capi/src/lib.rs, crates/capi/src/abstract_.rs	Module abstract_ is declared in the crate root. Imports for PyObject, with_vm, and c_int are established in the new module.
Item access FFI wrappers crates/capi/src/abstract_.rs	PyObject_GetItem, PyObject_SetItem, and PyObject_DelItem expose subscript-like operations as C-ABI wrappers, converting raw pointers and forwarding to underlying PyObject methods within a VM context.
Type checking FFI wrappers crates/capi/src/abstract_.rs	PyObject_IsSubclass and PyObject_IsInstance expose type relationship checks as C-ABI wrappers, dereferencing raw class/instance pointers and forwarding to the corresponding PyObject methods.

sequenceDiagram
  participant Caller
  participant PyObject_FFI
  participant VM
  participant PyObject
  Caller->>PyObject_FFI: PyObject_GetItem(obj, key)
  PyObject_FFI->>VM: with_vm(call get_item on obj)
  VM->>PyObject: get_item(key)
  PyObject-->>VM: result PyObject*
  VM-->>PyObject_FFI: returned pointer
  PyObject_FFI-->>Caller: result pointer

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Poem

🐰 I hopped through FFI and found,

Pointers wrapped and calls unbound.
Get and Set beneath the VM moon,
Delete and check — a quick buffoon.
Rust carrots, C-ABI tune.

🚥 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 accurately describes the main change: adding FFI functions for object protocol methods (get_item, set_item, del_item, is_subclass, is_instance) to the c-api module.
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/abstract_.rs`:
- Around line 5-11: The exported FFI function(s) like PyObject_GetItem (and the
other four exported functions in this module) currently have safe fn signatures
but dereference raw pointers (unsafe { &*obj }), so change their signatures to
pub unsafe extern "C" fn ... to reflect the required caller-safety contract;
update all five exported functions' declarations (keeping extern "C" and return
types) to be unsafe, and ensure any internal unsafe blocks remain as needed so
the functions properly express that callers must provide valid, non-null,
aligned pointers.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

Push a commit to this branch (recommended)
Create a new PR with the fixes

ℹ️ Review info ⚙️ Run configuration

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Review profile: CHILL

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Run ID: 29e4e1e8-0de0-495c-b69c-06e5355b891e

📥 Commits

Reviewing files that changed from the base of the PR and between 0871bc8 and 6a28e4e.

📒 Files selected for processing (2)

crates/capi/src/abstract_.rs
crates/capi/src/lib.rs

coderabbitai Bot reviewed May 16, 2026

View reviewed changes

Comment thread crates/capi/src/abstract_.rs Outdated

bschoenmaeckers force-pushed the c-api-abstract branch from 6a28e4e to 8cc3821 Compare May 16, 2026 11:24

youknowone approved these changes May 16, 2026

View reviewed changes

Add object protocol methods to c-api

4357f78

bschoenmaeckers force-pushed the c-api-abstract branch from 8cc3821 to 4357f78 Compare May 16, 2026 18:29

youknowone merged commit 3a56f37 into RustPython:main May 17, 2026
26 checks passed

bschoenmaeckers deleted the c-api-abstract branch May 17, 2026 11:34

coderabbitai Bot mentioned this pull request May 20, 2026

Add call functions to c-api #7937

Merged

This was referenced Jun 1, 2026

Update PyO3 to 0.29 & enable c-api tests #8000

Merged

Add mapping c-api functions #8003

Merged

Add number protocol functions to c-api #8005

Merged

This was referenced Jun 25, 2026

Add allocator functions to c-api #8168

Merged

Add more abstract functions to c-api #8202

Merged

Add object protocol methods to c-api by bschoenmaeckers · Pull Request #7882 · RustPython/RustPython · GitHub

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Add object protocol methods to c-api - #7882

Add object protocol methods to c-api#7882
youknowone merged 1 commit into
RustPython:mainfrom
bschoenmaeckers:c-api-abstract

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Add object protocol methods to c-api by bschoenmaeckers · Pull Request #7882 · RustPython/RustPython · GitHub

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Add object protocol methods to c-api - #7882

Add object protocol methods to c-api#7882youknowone merged 1 commit intoRustPython:mainRustPython/RustPython:mainfrom bschoenmaeckers:c-api-abstractbschoenmaeckers/RustPython:c-api-abstractCopy head branch name to clipboard

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Walkthrough

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Add object protocol methods to c-api#7882
youknowone merged 1 commit into
RustPython:mainfrom
bschoenmaeckers:c-api-abstract

bschoenmaeckers commented May 16, 2026 •
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