Minor updates to changelog generation script (#21038)

Author: JukkaL

misc/generate_changelog.py

@@ -83,7 +83,7 @@ def filter_omitted_commits(commits: list[CommitInfo]) -> list[CommitInfo]:
         ):
             # These are generated by a typeshed sync.
             keep = False
-        if re.search(r"(bump|update).*version.*\+dev", title.lower()):
+        if re.search(r"(bump|update).*version", title.lower()):
             # Version number updates aren't mentioned
             keep = False
         if "pre-commit autoupdate" in title:
@@ -155,13 +155,19 @@ def format_changelog_entry(c: CommitInfo) -> str:
 
 
 def main() -> None:
-    parser = argparse.ArgumentParser()
+    parser = argparse.ArgumentParser(
+        description="Generate draft .md changelog for a mypy public release and print it to stdout."
+    )
     parser.add_argument("version", help="target mypy version (form X.Y)")
-    parser.add_argument("--local", action="store_true")
+    parser.add_argument(
+        "--local", action="store_true", help="use local release branch, not origin"
+    )
     args = parser.parse_args()
     version: str = args.version
     local: bool = args.local
 
+    version = version.removeprefix("v")
+
     if not re.match(r"[0-9]+\.[0-9]+$", version):
         sys.exit(f"error: Release must be of form X.Y (not {version!r})")
     major, minor = (int(component) for component in version.split("."))
@@ -187,7 +193,10 @@ def main() -> None:
     print(f"Generating changelog for {major}.{minor}")
     print(f"Previous release was     {prev_major}.{prev_minor}")
 
-    new_branch = f"origin/release-{major}.{minor}"
+    if local:
+        new_branch = f"release-{major}.{minor}"
+    else:
+        new_branch = f"origin/release-{major}.{minor}"
     old_branch = f"origin/release-{prev_major}.{prev_minor}"
 
     changes = find_changes_between_releases(old_branch, new_branch)