Automate bilingual changelog generation before publication

tools/render-changelog.py

@@ -0,0 +1,76 @@
+#!/usr/bin/env python3
+"""Generate the public FR/EN changelogs from changelog.json (standard library only)."""
+import argparse
+import json
+import os
+from pathlib import Path
+import re
+import tempfile
+
+ROOT = Path(__file__).resolve().parents[1]
+OUTPUTS = {"fr": "CHANGELOG.md", "en": "CHANGELOG.en.md"}
+
+
+def render(source):
+    if source.get("schema") != 1 or not isinstance(source.get("entries"), list):
+        raise ValueError("Unsupported changelog schema")
+    ids = set()
+    for entry in source["entries"]:
+        identifier = entry["id"]
+        if not re.fullmatch(r"[A-Za-z0-9_.-]+", identifier) or identifier in ids:
+            raise ValueError("Invalid or duplicate entry id: " + identifier)
+        ids.add(identifier)
+    if not ids:
+        raise ValueError("The changelog must not be empty")
+    documents = {}
+    for language, filename in OUTPUTS.items():
+        preamble = source["preamble"][language].strip()
+        if not preamble.startswith("# "):
+            raise ValueError("Missing preamble for " + language)
+        sections = [preamble]
+        for entry in source["entries"]:
+            body = entry["text"][language].strip()
+            if not body.startswith("## "):
+                raise ValueError("Missing heading: " + entry["id"] + "/" + language)
+            sections.append('<a id="' + entry["id"] + '"></a>\n\n' + body)
+        documents[filename] = "\n\n".join(sections) + "\n"
+    return documents
+
+
+def generate(root=ROOT, check=False):
+    documents = render(json.loads((root / "changelog.json").read_text(encoding="utf-8")))
+    changed = []
+    for filename, content in documents.items():
+        path = root / filename
+        if path.exists() and path.read_text(encoding="utf-8") == content:
+            continue
+        changed.append(filename)
+        if check:
+            continue
+        descriptor, temporary = tempfile.mkstemp(prefix=".changelog-", dir=root)
+        try:
+            with os.fdopen(descriptor, "w", encoding="utf-8", newline="\n") as stream:
+                stream.write(content)
+            os.chmod(temporary, 0o644)
+            os.replace(temporary, path)
+        finally:
+            if os.path.exists(temporary):
+                os.unlink(temporary)
+    return changed
+
+
+def main():
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument("--check", action="store_true", help="Fail if generated files are out of date")
+    args = parser.parse_args()
+    try:
+        changed = generate(check=args.check)
+    except (ValueError, KeyError, TypeError, AttributeError) as error:
+        parser.exit(2, "Invalid changelog: " + str(error) + "\n")
+    if changed:
+        print(("Out of date: " if args.check else "Generated: ") + ", ".join(changed))
+    return 1 if args.check and changed else 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())