ci: locate draft Python candidates before promotion

.github/scripts/select-release-by-tag.py

@@ -0,0 +1,27 @@
+"""Select exactly one release from paginated GitHub API output, including drafts."""
+
+from __future__ import annotations
+
+import argparse
+import json
+import sys
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument("tag")
+    args = parser.parse_args()
+    pages = json.load(sys.stdin)
+    if not isinstance(pages, list) or not all(isinstance(page, list) for page in pages):
+        parser.error("expected paginated release arrays")
+    releases = [release for page in pages for release in page]
+    if not all(isinstance(release, dict) for release in releases):
+        parser.error("expected release objects")
+    matches = [release for release in releases if release.get("tag_name") == args.tag]
+    if len(matches) != 1:
+        parser.error(f"expected exactly one release for tag {args.tag}")
+    json.dump(matches[0], sys.stdout)
+
+
+if __name__ == "__main__":
+    main()

.github/workflows/publish.yml

@@ -24,6 +24,10 @@ jobs:
     environment: pypi
     runs-on: ubuntu-latest
     steps:
+      - name: Check out trusted release policy
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        with:
+          persist-credentials: false
       - name: Find matching release candidate
         id: release
         shell: bash
@@ -36,7 +40,9 @@ jobs:
             echo "invalid release tag: ${RELEASE_TAG}" >&2
             exit 1
           fi
-          if [[ "$(gh api "repos/${GITHUB_REPOSITORY}/releases/tags/${RELEASE_TAG}" --jq '.draft')" != true ]]; then
+          release=$(gh api --paginate --slurp "repos/${GITHUB_REPOSITORY}/releases?per_page=100" |
+            python .github/scripts/select-release-by-tag.py "$RELEASE_TAG")
+          if [[ "$(jq -r '.draft' <<<"$release")" != true ]]; then
             echo "GitHub release ${RELEASE_TAG} must still be a draft" >&2
             exit 1
           fi

tests/unit/test_release_selector.py

@@ -0,0 +1,45 @@
+from __future__ import annotations
+
+import json
+import subprocess
+import sys
+from pathlib import Path
+
+import pytest
+
+SCRIPT = Path(__file__).parents[2] / ".github/scripts/select-release-by-tag.py"
+
+
+def select(pages: object) -> subprocess.CompletedProcess[str]:
+    return subprocess.run(
+        [sys.executable, str(SCRIPT), "v0.7.0"],
+        input=json.dumps(pages),
+        text=True,
+        capture_output=True,
+        check=False,
+    )
+
+
+def test_draft_on_later_page_is_selected() -> None:
+    draft = {"id": 42, "tag_name": "v0.7.0", "draft": True}
+    result = select([[{"tag_name": "v0.6.0"}], [draft]])
+    assert result.returncode == 0, result.stderr
+    assert json.loads(result.stdout) == draft
+
+
+@pytest.mark.parametrize(
+    "pages",
+    [
+        [],
+        [[]],
+        [[{"tag_name": "v0.6.0"}]],
+        [[{"tag_name": "v0.7.0"}], [{"tag_name": "v0.7.0"}]],
+        {},
+        [{"tag_name": "v0.7.0"}],
+        [[None]],
+    ],
+)
+def test_missing_duplicate_or_invalid_release_is_rejected(pages: object) -> None:
+    result = select(pages)
+    assert result.returncode != 0
+    assert result.stdout == ""