Rust ENDF-6 parser crate with Python bindings and a parity harness

.github/workflows/rust.yml

@@ -0,0 +1,126 @@
+name: Rust
+
+on:
+  workflow_dispatch:
+
+  pull_request:
+    branches:
+      - main
+      - local-develop
+  push:
+    branches:
+      - main
+      - local-develop
+
+jobs:
+  crate:
+    name: Crate
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v6
+
+      - uses: dtolnay/rust-toolchain@stable
+        with:
+          components: rustfmt, clippy
+
+      - uses: Swatinem/rust-cache@v2
+
+      - name: Format
+        run: cargo fmt --all --check
+
+      - name: Clippy
+        run: cargo clippy --all-targets -- -D warnings
+
+      # Debug and release both, because the parity tests compare floating
+      # point and the two profiles have caught different things.
+      - name: Test
+        run: |
+          cargo test
+          cargo test --release
+
+  # The crate declares rust-version = "1.74" and consumers will believe it.
+  # Nothing else here checks it: the other jobs run stable, which happily
+  # accepts APIs stabilised years later. The library only — dev-dependencies
+  # are free to need a newer compiler, since they reach nobody downstream.
+  msrv:
+    name: MSRV
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v6
+
+      - uses: dtolnay/rust-toolchain@1.74
+
+      - uses: Swatinem/rust-cache@v2
+
+      - name: Build on the declared minimum
+        run: cargo build -p endf
+
+  goldens:
+    name: Goldens reproduce
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v6
+
+      - uses: actions/setup-python@v6
+        with:
+          python-version: "3.12"
+
+      - name: Install
+        run: python -m pip install .[test]
+
+      # The golden files are what holds the Rust reader to the Python one, so
+      # a change that quietly rewrites them would defeat the whole harness.
+      #
+      # `--check` compares the dump text rather than the compressed bytes and
+      # prints the offending lines. Comparing bytes would fail on any machine
+      # whose liblzma is not the one that wrote the file, which says nothing
+      # about the reader.
+      - name: Check for drift
+        run: |
+          python tools/dump_golden.py --check
+          python tools/dump_chain_golden.py --check
+
+  bindings:
+    name: Python bindings
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python-version: ["3.10", "3.13"]
+    steps:
+      - uses: actions/checkout@v6
+
+      - uses: actions/setup-python@v6
+        with:
+          python-version: ${{ matrix.python-version }}
+
+      - uses: dtolnay/rust-toolchain@stable
+
+      - uses: Swatinem/rust-cache@v2
+
+      - name: Install
+        run: |
+          python -m pip install -U pip
+          python -m pip install .[test] maturin
+
+      # An abi3 wheel, so one build serves every supported Python.
+      - name: Build the extension module
+        run: maturin build --release -m crates/endf-py/Cargo.toml -o dist
+
+      - name: Install the extension module
+        run: python -m pip install --no-index --find-links dist endf-py
+
+      # The bindings' tests compare the extension against the pure-Python
+      # reader on the same fixtures, so they only mean anything once it is
+      # installed. Fail rather than skip if the import did not take.
+      - name: Test
+        run: |
+          python -c "import _endf"
+          python -m pytest -ra tests/test_rust_bindings.py tests/test_rust_stub.py
+
+      # The stub is only worth shipping if a type checker can use it. This
+      # fails on a stub that is present but wrong, which the name comparison
+      # in test_rust_stub.py cannot see.
+      - name: Type-check against the stub
+        run: |
+          python -m pip install mypy
+          python -m mypy --strict crates/endf-py/typecheck.py

.gitignore

@@ -8,3 +8,6 @@ doc/build/
 *.so
 generated/
 wheelhouse/
+
+# Rust
+/target

Cargo.toml

@@ -0,0 +1,14 @@
+[workspace]
+resolver = "2"
+members = ["crates/endf", "crates/endf-py"]
+
+[workspace.package]
+version = "0.1.0"
+edition = "2021"
+license = "MIT"
+repository = "https://github.com/paulromano/endf-python"
+rust-version = "1.74"
+
+[profile.release]
+lto = true
+codegen-units = 1