Create the GitHub release automatically, not just the tag

.github/publish-git-tag.sh

@@ -1,24 +1,43 @@
 #!/usr/bin/env bash
-# Tag the commit that published this version.
+# Tag the commit that published this version, and create its GitHub release.
 #
 # Run from the publish job after the version bump has landed on main. Exits
-# non-zero if tagging fails, so a broken release is visible rather than silent.
+# non-zero if either step fails, so a broken release is visible rather than
+# silent. Both steps are independently idempotent: an existing tag does not
+# stop the release from being created, so a rerun after a partial failure
+# finishes the job rather than passing with nothing done.
 set -euo pipefail
 
 PYTHON=$(command -v python || command -v python3)
 VERSION=$("$PYTHON" -c "import re, pathlib; print(re.search(r'^version\s*=\s*\"(\d+\.\d+\.\d+)\"', pathlib.Path('pyproject.toml').read_text(), re.M).group(1))")
 TAG="v${VERSION}"
 
-if git rev-parse -q --verify "refs/tags/${TAG}" >/dev/null; then
-  echo "Tag ${TAG} already exists locally; nothing to do."
-  exit 0
+# The remote is the only state that matters here: gh release create
+# --verify-tag reads the tag from the remote, so a tag that exists only
+# locally must still be pushed. Decide on the remote, then make the local
+# tag match and push it.
+if git ls-remote --exit-code --tags origin "refs/tags/${TAG}" >/dev/null 2>&1; then
+  echo "Tag ${TAG} already exists on the remote."
+else
+  echo "Tagging ${TAG}"
+  # Create it only if it is not already here; git tag fails on an existing name.
+  git rev-parse -q --verify "refs/tags/${TAG}" >/dev/null || git tag "${TAG}"
+  git push origin "${TAG}"
 fi
 
-if git ls-remote --exit-code --tags origin "refs/tags/${TAG}" >/dev/null 2>&1; then
-  echo "Tag ${TAG} already exists on the remote; nothing to do."
+# Zenodo archives on the GitHub release, not on the tag, so a tag alone leaves
+# the DOI pointing at whatever was last released by hand.
+if gh release view "${TAG}" >/dev/null 2>&1; then
+  echo "Release ${TAG} already exists."
   exit 0
 fi
 
-echo "Tagging ${TAG}"
-git tag "${TAG}"
-git push origin "${TAG}"
+# --verify-tag so gh aborts if the tag is missing from the remote, rather than
+# creating one itself at the default branch head.
+echo "Creating release ${TAG}"
+NOTES=$("$PYTHON" .github/release_notes.py "${VERSION}" 2>/dev/null || true)
+if [ -n "${NOTES}" ]; then
+  printf '%s\n' "${NOTES}" | gh release create "${TAG}" --title "${TAG}" --verify-tag --notes-file -
+else
+  gh release create "${TAG}" --title "${TAG}" --verify-tag --generate-notes
+fi

.github/release_notes.py

@@ -0,0 +1,23 @@
+"""Print the CHANGELOG section for one version, for use as release notes.
+
+towncrier writes the curated entry; `gh release create --generate-notes` would
+write a raw commit list instead. Prints nothing if the section is absent, and
+the caller falls back to generated notes.
+"""
+
+import re
+import sys
+from pathlib import Path
+
+
+def section_for(changelog: str, version: str) -> str:
+    pattern = rf"^## \[{re.escape(version)}\][^\n]*\n(.*?)(?=^## \[|\Z)"
+    match = re.search(pattern, changelog, re.M | re.S)
+    return match.group(1).strip() if match else ""
+
+
+if __name__ == "__main__":
+    path = Path("CHANGELOG.md")
+    if not path.exists():
+        sys.exit(0)
+    print(section_for(path.read_text(), sys.argv[1]))

.github/workflows/versioning.yaml

@@ -79,5 +79,7 @@ jobs:
             skip-existing: true
         # After the upload, so a tag failure can never hold back a release.
         # skip-existing above keeps a rerun safe.
-        - name: Publish a git tag
+        - name: Publish a git tag and GitHub release
           run: ".github/publish-git-tag.sh"
+          env:
+            GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}

changelog.d/auto-release.changed.md

@@ -0,0 +1 @@
+Releases are now created automatically from the tag, so Zenodo archives every version rather than only those released by hand.