Vendor Rust crates into source distributions

`vendor_rust()` takes an existing sdist tar ball and creates a new sdist
with all Rust crates vendored. This allows offline compilation without
downloading any Rust crates at build time.

Switch from `tomli` to `toml`. The `tomli` package does not have write
support.

I have successfully wheel builds with vendored crates for

- `cryptography-42.0.7.tar.gz`
- `maturin-1.5.1.tar.gz`
- `pydantic_core-2.18.4.tar.gz`
- `setuptools-rust-1.9.0.tar.gz`

with `CARGO_NET_OFFLINE=true python3 -m build -w`.

Signed-off-by: Christian Heimes <[email protected]>

.github/workflows/test.yaml

@@ -16,6 +16,9 @@ jobs:
           - "3.10"
           - "3.11"
           - "3.12"
+        rust-version:
+          # RHEL 9.4 has rustc 1.75
+          - "1.75"
 
     steps:
       - name: Get source
@@ -26,6 +29,13 @@ jobs:
         with:
           python-version: ${{ matrix.python-version }}
 
+      - name: Set up Rust ${{ matrix.rust-version }}
+        uses: actions-rs/toolchain@v1
+        with:
+          toolchain: ${{ matrix.rust-version }}
+          default: true
+          override: true
+
       - name: Install dependencies
         run: python -m pip install tox
 
@@ -43,6 +53,9 @@ jobs:
           - "3.10"
           - "3.11"
           - "3.12"
+        rust-version:
+          # RHEL 9.4 has rustc 1.75
+          - "1.75"
         test-script:
           - bootstrap
           - report_missing_dependency
@@ -58,6 +71,13 @@ jobs:
         with:
           python-version: ${{ matrix.python-version }}
 
+      - name: Set up Rust ${{ matrix.rust-version }}
+        uses: actions-rs/toolchain@v1
+        with:
+          toolchain: ${{ matrix.rust-version }}
+          default: true
+          override: true
+
       - name: Install dependencies
         run: python -m pip install tox
 

.gitignore

@@ -18,3 +18,8 @@ __pycache__/
 /package.json
 /e2e-output/
 /dist/
+/e2e/pyo3_test/.cargo
+/e2e/pyo3_test/build
+/e2e/pyo3_test/dist
+/e2e/pyo3_test/target
+/e2e/pyo3_test/vendor

e2e/pyo3_test/Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+name = "pyo3_test"
+version = "1.0.0"
+edition = "2021"
+
+[dependencies]
+pyo3 = { version = "0.21.2", features = ["gil-refs"] }
+
+[lib]
+name = "_lib"
+crate-type = ["cdylib"]
+path = "rust/lib.rs"

e2e/pyo3_test/MANIFEST.in

@@ -0,0 +1,4 @@
+graft python
+graft rust
+include Cargo.toml Cargo.lock tests.py tox.ini
+exclude .cargo vendor

e2e/pyo3_test/pyproject.toml

@@ -0,0 +1,13 @@
+[build-system]
+requires = ["setuptools", "setuptools-rust"]
+build-backend = "setuptools.build_meta"
+
+[project]
+name = "pyo3_test"
+version = "1.0.0"
+
+[tool.setuptools.packages]
+find = { where = ["python"] }
+
+[[tool.setuptools-rust.ext-modules]]
+target = "pyo3_test._lib"

e2e/pyo3_test/python/pyo3_test/__init__.py

@@ -0,0 +1,3 @@
+from ._lib import add
+
+__all__ = ["add"]