Docathon automation: Add script to sync labels from issue to PR (pytorch#19374)

Adds python script for workflow:
.github/workflows/docathon-sync-label.yml



cc @mergennachin @AlannaBurke

Author: nil-is-all

.github/scripts/docathon-label-sync.py

@@ -0,0 +1,54 @@
+import os
+import re
+import sys
+
+from github import Github
+
+
+def main() -> None:
+    token = os.environ.get("GITHUB_TOKEN")
+
+    repo_owner = "pytorch"
+    repo_name = "pytorch"
+    pull_request_number = int(sys.argv[1])
+
+    g = Github(token)
+    repo = g.get_repo(f"{repo_owner}/{repo_name}")
+    pull_request = repo.get_pull(pull_request_number)
+    pull_request_body = pull_request.body
+    # PR without description
+    if pull_request_body is None:
+        return
+
+    # get issue number from the PR body
+    if not re.search(r"#\d{1,6}", pull_request_body):
+        print("The pull request does not mention an issue.")
+        return
+    issue_number = int(re.findall(r"#(\d{1,6})", pull_request_body)[0])
+    issue = repo.get_issue(issue_number)
+    issue_labels = issue.labels
+    docathon_label_present = any(
+        label.name == "docathon-2026" for label in issue_labels
+    )
+
+    # if the issue has a docathon label, add all labels from the issue to the PR.
+    if not docathon_label_present:
+        print("The 'docathon-2026' label is not present in the issue.")
+        return
+    pull_request_labels = pull_request.get_labels()
+    pull_request_label_names = [label.name for label in pull_request_labels]
+    issue_label_names = [label.name for label in issue_labels]
+    labels_to_add = [
+        label
+        for label in issue_label_names
+        if label not in pull_request_label_names and label != "actionable"
+    ]
+    if not labels_to_add:
+        print("The pull request already has the same labels.")
+        return
+    pull_request.add_to_labels(*labels_to_add)
+    print("Labels added to the pull request!")
+
+
+if __name__ == "__main__":
+    main()