add CI release workflow

.github/workflows/release.yml

@@ -0,0 +1,127 @@
+name: Release
+
+on:
+  push:
+    tags:
+      - "v*"
+
+# Publishing permissions are granted only to the jobs that need them.
+permissions:
+  contents: read
+
+concurrency:
+  group: release-${{ github.ref }}
+  cancel-in-progress: false
+
+jobs:
+  verify-version:
+    name: Verify release version
+    runs-on: ubuntu-latest
+    steps:
+      - name: Reject releases outside the canonical repository
+        if: github.repository != 'lrntct/xarray-grass'
+        run: |
+          echo "Releases may only run from lrntct/xarray-grass." >&2
+          exit 1
+
+      - uses: actions/checkout@v6
+
+      - name: Verify the tag and package version
+        run: python3 scripts/release_checks.py verify-version "$GITHUB_REF_NAME"
+
+  test:
+    name: Test release
+    needs: verify-version
+    uses: ./.github/workflows/tests.yml
+
+  build:
+    name: Build release artifacts
+    needs: verify-version
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v6
+
+      - uses: actions/setup-python@v6
+        with:
+          python-version: "3.14"
+
+      - name: Build source and wheel distributions
+        run: |
+          python -m pip install --disable-pip-version-check --upgrade build
+          python -m build
+
+      - uses: actions/upload-artifact@v6
+        with:
+          name: distributions
+          path: dist/
+          if-no-files-found: error
+
+  validate-artifacts:
+    name: Validate release artifacts
+    needs: [test, build]
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v6
+
+      - uses: actions/setup-python@v6
+        with:
+          python-version: "3.14"
+
+      - uses: actions/download-artifact@v6
+        with:
+          name: distributions
+          path: dist
+
+      - name: Verify artifact versions and coverage
+        run: python scripts/release_checks.py verify-artifacts dist "$GITHUB_REF_NAME"
+
+      - name: Check distribution metadata
+        run: |
+          python -m pip install --disable-pip-version-check --upgrade twine
+          python -m twine check dist/*
+
+      - name: Install the source distribution
+        run: |
+          python -m venv sdist-venv
+          sdist-venv/bin/python -m pip install --no-deps dist/*.tar.gz
+          sdist-venv/bin/python -m pip show xarray-grass
+
+  publish-pypi:
+    name: Publish to PyPI
+    needs: validate-artifacts
+    runs-on: ubuntu-latest
+    environment:
+      name: pypi
+    permissions:
+      id-token: write
+    steps:
+      - uses: actions/download-artifact@v6
+        with:
+          name: distributions
+          path: dist
+
+      - uses: pypa/gh-action-pypi-publish@release/v1
+        with:
+          packages-dir: dist/
+
+  create-github-release:
+    name: Create GitHub release
+    needs: publish-pypi
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+    steps:
+      - uses: actions/download-artifact@v6
+        with:
+          name: distributions
+          path: dist
+
+      - name: Create release and upload artifacts
+        env:
+          GH_TOKEN: ${{ github.token }}
+          RELEASE_TAG: ${{ github.ref_name }}
+        run: |
+          gh release create "$RELEASE_TAG" dist/* \
+            --repo "$GITHUB_REPOSITORY" \
+            --title "$RELEASE_TAG" \
+            --generate-notes

.github/workflows/tests.yml

@@ -1,6 +1,7 @@
 name: tests
 
 on:
+  workflow_call:
   push:
     branches: ["main"]
   pull_request:

scripts/release_checks.py

@@ -0,0 +1,109 @@
+from __future__ import annotations
+
+import argparse
+import ast
+import re
+import tarfile
+import zipfile
+from email.parser import BytesParser
+from pathlib import Path, PurePosixPath
+
+PROJECT_NAME = "xarray-grass"
+VERSION_FILE = Path("src/xarray_grass/__init__.py")
+
+
+def version_from_tag(tag: str) -> str:
+    if not re.fullmatch(r"v\d+\.\d+\.\d+", tag):
+        raise SystemExit(f"Release tags must use the vX.Y.Z format, got {tag!r}.")
+    return tag[1:]
+
+
+def version_from_source(version_file: Path) -> str:
+    module = ast.parse(version_file.read_text(), filename=str(version_file))
+    for statement in module.body:
+        if not isinstance(statement, ast.Assign):
+            continue
+        if any(
+            isinstance(target, ast.Name) and target.id == "__version__"
+            for target in statement.targets
+        ):
+            value = ast.literal_eval(statement.value)
+            if isinstance(value, str):
+                return value
+    raise SystemExit(f"Could not find a string __version__ in {version_file}.")
+
+
+def verify_version(tag: str, version_file: Path) -> None:
+    tag_version = version_from_tag(tag)
+    source_version = version_from_source(version_file)
+    if source_version != tag_version:
+        raise SystemExit(
+            f"Tag {tag!r} does not match package version {source_version!r}."
+        )
+
+
+def verify_metadata(metadata_bytes: bytes, artifact: Path, version: str) -> None:
+    metadata = BytesParser().parsebytes(metadata_bytes)
+    if metadata["Name"] != PROJECT_NAME or metadata["Version"] != version:
+        raise SystemExit(
+            f"{artifact} has {metadata['Name']} {metadata['Version']}, "
+            f"expected {PROJECT_NAME} {version}."
+        )
+
+
+def verify_artifacts(dist: Path, tag: str) -> None:
+    version = version_from_tag(tag)
+    sdists = list(dist.glob("*.tar.gz"))
+    wheels = list(dist.glob("*.whl"))
+
+    if len(sdists) != 1:
+        raise SystemExit(f"Expected one sdist, found {len(sdists)}: {sdists}")
+    if len(wheels) != 1:
+        raise SystemExit(f"Expected one wheel, found {len(wheels)}: {wheels}")
+
+    with tarfile.open(sdists[0]) as archive:
+        metadata_files = [
+            member
+            for member in archive.getmembers()
+            if PurePosixPath(member.name).name == "PKG-INFO"
+            and len(PurePosixPath(member.name).parts) == 2
+        ]
+        if len(metadata_files) != 1:
+            raise SystemExit(f"Could not identify sdist metadata in {sdists[0]}.")
+        metadata_file = archive.extractfile(metadata_files[0])
+        if metadata_file is None:
+            raise SystemExit(f"Could not read sdist metadata in {sdists[0]}.")
+        verify_metadata(metadata_file.read(), sdists[0], version)
+
+    with zipfile.ZipFile(wheels[0]) as archive:
+        metadata_files = [
+            name for name in archive.namelist() if name.endswith(".dist-info/METADATA")
+        ]
+        if len(metadata_files) != 1:
+            raise SystemExit(f"Could not identify wheel metadata in {wheels[0]}.")
+        verify_metadata(archive.read(metadata_files[0]), wheels[0], version)
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser(
+        description="Validate release versions and artifacts."
+    )
+    subparsers = parser.add_subparsers(dest="command", required=True)
+
+    version_parser = subparsers.add_parser("verify-version")
+    version_parser.add_argument("tag")
+    version_parser.add_argument("--version-file", type=Path, default=VERSION_FILE)
+
+    artifacts_parser = subparsers.add_parser("verify-artifacts")
+    artifacts_parser.add_argument("dist", type=Path)
+    artifacts_parser.add_argument("tag")
+
+    args = parser.parse_args()
+    if args.command == "verify-version":
+        verify_version(args.tag, args.version_file)
+    else:
+        verify_artifacts(args.dist, args.tag)
+
+
+if __name__ == "__main__":
+    main()