Cut the release from the changelog heading on a green main instead of a hand-pushed tag

.github/workflows/test.yml

@@ -49,3 +49,21 @@ jobs:
       - name: Lowest supported Go
         if: ${{ !cancelled() && steps.changes.outputs.code == 'true' }}
         run: docker build --build-arg GO_VERSION=1.22.12 .
+
+  release:
+    name: Gitea release from CHANGELOG.md
+    needs: test
+    if: github.event_name == 'push'
+    runs-on: ubuntu-24.04
+    permissions:
+      contents: write
+    steps:
+      - uses: actions/checkout@v6
+        with:
+          persist-credentials: false
+      - run: python3 release-tooling/publish_release.py
+        env:
+          GITEA_API_URL: ${{ github.api_url }}
+          GITEA_REPOSITORY: ${{ github.repository }}
+          GITEA_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          SHA: ${{ github.sha }}

README.md

@@ -559,7 +559,8 @@ with no breaking change. From `v2` the module path carries `/vN`, so fences ship
 batched into as few majors as possible.
 
 [`testdata/shipped_shape.txt`](testdata/shipped_shape.txt) pins every path, each
-category's format and each column's datatype and nullability; a pull request that
+category's format and the categories it reads, and each column's datatype and
+nullability; a pull request that
 changes it or `data/` adds its `CHANGELOG.md` entry, which CI checks. A removed,
 renamed or retyped line is a major.
 
@@ -667,10 +668,11 @@ renamed or retyped line is a major.
 - **Raising the lowest supported Go is a major.** A consumer building on it breaks,
   which is the one test every rule above applies; Go's convention of a minor is not
   followed.
-- **A release is a Gitea release built from the changelog.** The tag alone serves
+- **The changelog heading is the one spelling of a release; CI cuts the tag.** A
-  `go get`, but prebuilt binaries need release assets, and the body being the tag's
+  tag pushed by hand is served by `go get` at once, so a tag whose commit lacks its
-  changelog section keeps one text; a tag with no heading fails the workflow
+  heading is burnt, not fixed. The heading on a gate-passed `main` commit is the
-  rather than publishing an empty release.
+  trigger instead: the tag can land only there, and the Gitea release the same job
+  publishes keeps one text as its body and is where prebuilt binaries will attach.
 - **A `--data-path` override rebinds every reference to the category it
   replaces.** References bind against the merged tree, so once shipped data uses
   `{.person}`, a consumer's `sv_SE/person.json` is what every shipped reference
@@ -837,13 +839,10 @@ in its own commit:
 REPIN=1 docker compose run --rm --user "$(id -u):$(id -g)" test
 ```
 
-To release, head `CHANGELOG.md` with the version's section in place of `Unreleased`,
+To release, head `CHANGELOG.md` with the version's section in place of `Unreleased`
-merge, then tag `main`; the release workflow publishes the Gitea release with that
+and merge: once `main` passes the gate, CI tags that commit `vX.Y.Z` and publishes
-section as its body:
+the Gitea release with the section as its body. A top heading of `[Unreleased]`
-
+publishes nothing.
-```sh
-git tag -a v0.1.0 -m v0.1.0 && git push origin v0.1.0
-```
 
 ## Layout
 
@@ -867,7 +866,7 @@ value.go        the value proof: what a typed column or calc operand holds, chec
 data.go         data loading: fs.FS folders/files -> namespace tree, multi-source merge
 cmd/fejkdata/   the fejkdata CLI
 data/           shipped data (JSON), embedded at build: locale folders + a misc folder
-release-tooling/ the Gitea release a tag publishes
+release-tooling/ the release CI publishes from the changelog heading
 testdata/       the pinned shipped shape (see Versioning)
 ```
 

release-tooling/publish_release.py

@@ -1,38 +1,52 @@
 #!/usr/bin/env python3
-"""Create the Gitea release for a tag, its body the tag's CHANGELOG.md section.
+"""Publish the Gitea release that CHANGELOG.md's top heading names, tagging SHA.
 
-Env: GITEA_API_URL, GITEA_REPOSITORY (owner/repo), GITEA_TOKEN, TAG (vX.Y.Z).
+A top heading of `[Unreleased]`, or a version already released, publishes nothing.
+Env: GITEA_API_URL, GITEA_REPOSITORY (owner/repo), GITEA_TOKEN, SHA.
 """
 
 import json
 import os
 import re
 import sys
+import urllib.error
 import urllib.request
 
-
+HEADING = re.compile(r"^## \[([^\]]+)\].*?$\n(.*?)(?=^## \[|\Z)", re.M | re.S)
-def section(changelog: str, version: str) -> str | None:
-	m = re.search(rf"^## \[{re.escape(version)}\].*?$\n(.*?)(?=^## \[|\Z)", changelog, re.M | re.S)
-	return m.group(1).strip() if m else None
 
 
-def main() -> int:
+def request(path: str, data: dict | None = None):
-	tag = os.environ["TAG"]
-	if not re.fullmatch(r"v\d+\.\d+\.\d+", tag):
-		print(f"{tag}: not a release tag; a release is vX.Y.Z", file=sys.stderr)
-		return 1
-	with open("CHANGELOG.md", encoding="utf-8") as f:
-		body = section(f.read(), tag[1:])
-	if body is None:
-		print(f"CHANGELOG.md has no `## [{tag[1:]}]` heading; add the section, then tag", file=sys.stderr)
-		return 1
 	req = urllib.request.Request(
-		f"{os.environ['GITEA_API_URL']}/repos/{os.environ['GITEA_REPOSITORY']}/releases",
+		f"{os.environ['GITEA_API_URL']}/repos/{os.environ['GITEA_REPOSITORY']}/{path}",
-		data=json.dumps({"body": body, "name": tag, "tag_name": tag}).encode(),
+		data=json.dumps(data).encode() if data else None,
 		headers={"Authorization": f"token {os.environ['GITEA_TOKEN']}", "Content-Type": "application/json"},
 	)
 	with urllib.request.urlopen(req) as resp:
-		print(json.load(resp)["html_url"])
+		return json.load(resp)
+
+
+def main() -> int:
+	with open("CHANGELOG.md", encoding="utf-8") as f:
+		top = HEADING.search(f.read())
+	if top is None:
+		print("CHANGELOG.md has no `## [...]` heading", file=sys.stderr)
+		return 1
+	version, body = top.group(1), top.group(2).strip()
+	if version == "Unreleased":
+		print("top heading is Unreleased; nothing to publish")
+		return 0
+	if not re.fullmatch(r"\d+\.\d+\.\d+", version):
+		print(f"top heading `[{version}]` is neither Unreleased nor X.Y.Z", file=sys.stderr)
+		return 1
+	tag = f"v{version}"
+	try:
+		print(f"{tag} already published: {request(f'releases/tags/{tag}')['html_url']}")
+		return 0
+	except urllib.error.HTTPError as e:
+		if e.code != 404:
+			raise
+	release = request("releases", {"body": body, "name": tag, "tag_name": tag, "target_commitish": os.environ["SHA"]})
+	print(release["html_url"])
 	return 0