Add integer c-api support by bschoenmaeckers · Pull Request #7905 · RustPython/RustPython

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📥 Commits

Reviewing files that changed from the base of the PR and between 365c5d4 and fc76d83.

📒 Files selected for processing (2)

crates/capi/src/longobject.rs
crates/capi/src/object.rs

✅ Files skipped from review due to trivial changes (1)

crates/capi/src/object.rs

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

crates/capi/src/longobject.rs

📝 Walkthrough

Walkthrough

Adds a new longobject cAPI module: extern "C" PyLong constructors and extractors for multiple C integer types, plus an FfiResult implementation for c_ulonglong; includes a disabled test module.

Changes

Python Long Integer FFI Bindings

Layer / File(s)	Summary
Module declaration and imports `crates/capi/src/lib.rs`, `crates/capi/src/object.rs`, `crates/capi/src/longobject.rs`	Exposes `longobject` as a public module, re-exports `define_py_check` crate-wide, and declares `PyLong_Check`/`PyLong_CheckExact` plus top-level imports.
PyLong constructors from C integers `crates/capi/src/longobject.rs`	Six `PyLong_From*` extern "C" functions allocate Python ints from `c_long`, `c_longlong`, `isize`, `usize`, `c_ulong`, and `c_ulonglong` via `with_vm(
PyLong extraction to C integers `crates/capi/src/longobject.rs`	Unsafe `PyLong_AsLong` and `PyLong_AsUnsignedLongLong` dereference `*mut PyObject`, coerce to bigint/PyInt, attempt downcast to requested C type, and map failures to VM overflow errors with fixed messages.
Disabled test validation `crates/capi/src/longobject.rs`	`#[cfg(false)]` test module (pyo3) with disabled checks for i32 and u64 extraction; not compiled in normal builds.
FfiResult impl for c_ulonglong `crates/capi/src/util.rs`	Implements `FfiResult` for `c_ulonglong` with `ERR_VALUE = Self::MAX` and `into_output` returning the input value.

Sequence Diagram(s)

sequenceDiagram
  participant C_Caller
  participant FFI_Constructor as PyLong_From*
  participant VM_Context as with_vm
  participant VM_CTX as vm.ctx
  participant PyInt as Python_int
  C_Caller->>FFI_Constructor: call PyLong_From*(C integer)
  FFI_Constructor->>VM_Context: enter VM context
  VM_Context->>VM_CTX: vm.ctx.new_int(value)
  VM_CTX->>PyInt: create Python int object
  PyInt-->>FFI_Constructor: PyObject* returned
  FFI_Constructor-->>C_Caller: PyObject*

sequenceDiagram
  participant C_Caller
  participant FFI_Extractor as PyLong_As*
  participant PyObject_Ptr
  participant BigInt_Conversion
  participant VM_Context
  C_Caller->>FFI_Extractor: call PyLong_As*(PyObject*)
  FFI_Extractor->>PyObject_Ptr: dereference & coerce
  PyObject_Ptr->>BigInt_Conversion: extract bigint value
  BigInt_Conversion->>BigInt_Conversion: try downcast to C type
  alt success
    BigInt_Conversion-->>FFI_Extractor: numeric value
    FFI_Extractor-->>C_Caller: return C integer
  else overflow/failure
    BigInt_Conversion->>VM_Context: set overflow error
    VM_Context-->>FFI_Extractor: error indicator
    FFI_Extractor-->>C_Caller: error sentinel (ERR_VALUE)
  end

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

RustPython/RustPython#7787: Prior cAPI/FFI error and FfiResult plumbing related to capi util and VM-exception mapping.
RustPython/RustPython#7871: Introduced the define_py_check! macro usage for generating PyLong check functions.

Suggested reviewers

youknowone
ShaharNaveh

Poem

🐰 I hop from C to Python, numbers in my paw,

I stitch longs with care and check for overflow,
From Rusty roots I craft each tiny int,
A FFI bridge where rabbits dream and sprint,
Hooray — the bindings sing, and onward we go.

🚥 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 integer c-api support' directly and accurately summarizes the main purpose of the pull request: adding C-API support for Python integer objects through multiple FFI functions.
Docstring Coverage	✅ Passed	Docstring coverage is 83.33% 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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