Decouple standalone binaries from Python: make pyo3 optional and fix build-binaries workflow

Author: ForblazeProject

.github/workflows/PyPI.yml

@@ -28,7 +28,8 @@ jobs:
         uses: PyO3/maturin-action@v1
         with:
           target: ${{ matrix.target }}
-          args: --release --out dist --features extension-module
+          # Maturin will use [tool.maturin.features = ["python"]] from pyproject.toml
+          args: --release --out dist
           sccache: 'true'
           manylinux: auto
       - name: Upload wheels
@@ -63,6 +64,8 @@ jobs:
             target: aarch64-apple-darwin
             suffix: macos-aarch64
             binary_ext: ""
+    env:
+      PYO3_NO_PYTHON: 1 # Ensure pyo3-build-config doesn't look for Python
     steps:
       - uses: actions/checkout@v4
 
@@ -161,4 +164,4 @@ jobs:
         uses: softprops/action-gh-release@v2
         with:
           files: assets/*
-          generate_release_notes: true
+          generate_release_notes: true

Cargo.toml

@@ -23,8 +23,8 @@ name = "fbtk-build"
 path = "src/bin/build.rs"
 
 [dependencies]
-pyo3 = { version = "0.23", features = ["abi3-py38"] }
-numpy = "0.23"
+pyo3 = { version = "0.23", features = ["abi3-py38"], optional = true }
+numpy = { version = "0.23", optional = true }
 rayon = "1.10"
 anyhow = "1.0"
 serde = { version = "1.0", features = ["derive"] }
@@ -38,4 +38,5 @@ uff-relax = "1.0.0"
 glam = "0.31"
 
 [features]
+python = ["pyo3", "numpy", "extension-module"]
 extension-module = ["pyo3/extension-module"]

pyproject.toml

@@ -29,4 +29,4 @@ fbtk-build = "fbtk.cli:build"
 
 [tool.maturin]
 module-name = "fbtk.fbtk"
-features = ["pyo3/abi3-py38"]
+features = ["python"]

src/lib.rs

@@ -1,11 +1,17 @@
 pub mod core;
 pub mod parsers;
+
+#[cfg(feature = "python")]
 pub mod python;
 
+#[cfg(feature = "python")]
 use pyo3::prelude::*;
+#[cfg(feature = "python")]
 use crate::python::{PyBuilder, PySystem, PyMolecule};
+#[cfg(feature = "python")]
 use crate::python::functions::*;
 
+#[cfg(feature = "python")]
 #[pymodule]
 fn fbtk(m: &Bound<'_, PyModule>) -> PyResult<()> {
     // Thread pool initialization