Crate ommx_pyo3_bridge 

ommx-pyo3-bridge

ommx-pyo3-bridge converts values from the Rust ommx crate into the canonical classes provided by the installed Python ommx package. It is for independently built PyO3 extension modules that cannot safely pass Rust values or private PyO3 wrapper types across a shared-library boundary.

Use the bridge wrapper as the direct return type of a PyO3 function:

use ommx_pyo3_bridge::PyFunction;
use pyo3::prelude::*;

#[pyo3_stub_gen::derive::gen_stub_pyfunction]
#[pyfunction]
fn objective() -> PyFunction {
    ommx::Function::default().into()
}

At runtime this return value is an ommx.Function. pyo3-stub-gen also emits ommx.Function in the generated stub. The crate provides the same pattern for detached constraints, detached decision variables, and instances through PyConstraint, PyDecisionVariable, and PyInstance.

The consuming extension and the bridge must resolve a compatible PyO3 version. This release accepts PyO3 0.27.2 through the 0.29 release line and uses pyo3-stub-gen 0.23.

Transfer boundary

The bridge serializes each value to protobuf bytes, passes those bytes through the Python/PyO3 ABI, and asks the installed Python OMMX package to reconstruct its canonical class. These payloads are an ephemeral implementation detail of the bridge, not new persistence roots for component values.

The installed Python SDK owns the binding-private reconstruction endpoints because it owns the canonical Python classes. These endpoints are production bridge capabilities, not user-facing component serialization APIs.

This release uses internal bridge protocol v0 to identify the required endpoint signatures and payload interpretations. Protocol v0 is not a new persistence format, and the bridge performs no protocol negotiation. Rust and Python OMMX releases remain independently versioned, with no guarantee that arbitrary release pairs are compatible. Callers must install a Python OMMX release that provides the exact v0 capabilities expected by this crate. A missing endpoint produces an ImportError with the required capability name.

When a Python SDK exposes a v0 capability, its endpoint signature and payload interpretation have the fixed meaning recorded in tests/data/protocol_v0.json. An incompatible change must add a new protocol version instead of reinterpreting v0. This does not require every future Python SDK release to retain v0, and there is no negotiation or fallback between protocol versions.

Structs

PyConstraint

Output wrapper converting a detached Rust constraint into ommx.Constraint.

PyDecisionVariable

Output wrapper converting a detached Rust decision variable into ommx.DecisionVariable.

PyFunction

Output wrapper converting a Rust ommx::Function into ommx.Function.

PyInstance

Output wrapper converting a Rust ommx::Instance into ommx.Instance.