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3rd/CLI11/scripts/ExtractReleaseNotes.py

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+#!/usr/bin/env python3
+
+"""Print the CHANGELOG.md section for a version, for use as release notes.
+
+VERSION accepts a tag name ("v2.7.0") or a plain version ("2.7.0"). Older
+sections are titled with two components and a name, such as
+"## Version 2.5: Help Formatter", so "2.5.0" also matches "## Version 2.5".
+Each section keeps its own link definitions, so the output needs no fixup.
+
+With --title, print the section heading instead of the body; this is the name
+of the GitHub release.
+"""
+
+from __future__ import annotations
+
+import argparse
+import re
+from pathlib import Path
+
+
+def extract(text: str, version: str) -> tuple[str, str] | None:
+    """Return the heading and the body of the section for a version."""
+    heads = list(re.finditer(r"^## (Version (\S+?):?(?:[ \t].*)?)$", text, re.M))
+    for candidate in (version, version.rsplit(".", 1)[0]):
+        for i, head in enumerate(heads):
+            if head.group(2) != candidate:
+                continue
+            end = heads[i + 1].start() if i + 1 < len(heads) else len(text)
+            return head.group(1), text[head.end() : end].strip()
+    return None
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser(
+        description=__doc__, formatter_class=argparse.RawDescriptionHelpFormatter
+    )
+    parser.add_argument("version", help='tag ("v2.7.0") or version ("2.7.0")')
+    parser.add_argument("changelog", nargs="?", type=Path, default=Path("CHANGELOG.md"))
+    parser.add_argument(
+        "--title", action="store_true", help="print the heading, not the body"
+    )
+    args = parser.parse_args()
+
+    version = args.version.lstrip("v")
+    section = extract(args.changelog.read_text(encoding="utf-8"), version)
+    if section is None:
+        raise SystemExit(f"No '## Version {version}' section in {args.changelog}")
+    heading, notes = section
+    print(heading if args.title else notes)
+
+
+if __name__ == "__main__":
+    main()