Add release note label checker bot

Author: jackzhxng

.github/scripts/check_labels.py

@@ -0,0 +1,62 @@
+#!/usr/bin/env python3
+"""Check whether a PR has required labels."""
+
+import sys
+from typing import Any
+
+from github_utils import gh_delete_comment, gh_post_pr_comment
+from gitutils import get_git_remote_name, get_git_repo_dir, GitRepo
+from label_utils import has_required_labels, is_label_err_comment, LABEL_ERR_MSG
+from trymerge import GitHubPR
+
+
+def delete_all_label_err_comments(pr: "GitHubPR") -> None:
+    for comment in pr.get_comments():
+        if is_label_err_comment(comment):
+            gh_delete_comment(pr.org, pr.project, comment.database_id)
+
+
+def add_label_err_comment(pr: "GitHubPR") -> None:
+    # Only make a comment if one doesn't exist already
+    if not any(is_label_err_comment(comment) for comment in pr.get_comments()):
+        gh_post_pr_comment(pr.org, pr.project, pr.pr_num, LABEL_ERR_MSG)
+
+
+def parse_args() -> Any:
+    from argparse import ArgumentParser
+
+    parser = ArgumentParser("Check PR labels")
+    parser.add_argument("pr_num", type=int)
+    # add a flag to return a non-zero exit code if the PR does not have the required labels
+    parser.add_argument(
+        "--exit-non-zero",
+        action="store_true",
+        help="Return a non-zero exit code if the PR does not have the required labels",
+    )
+
+    return parser.parse_args()
+
+
+def main() -> None:
+    args = parse_args()
+    repo = GitRepo(get_git_repo_dir(), get_git_remote_name())
+    org, project = repo.gh_owner_and_name()
+    pr = GitHubPR(org, project, args.pr_num)
+
+    try:
+        if not has_required_labels(pr):
+            print(LABEL_ERR_MSG)
+            add_label_err_comment(pr)
+            if args.exit_non_zero:
+                sys.exit(1)
+        else:
+            delete_all_label_err_comments(pr)
+    except Exception as e:
+        if args.exit_non_zero:
+            sys.exit(1)
+
+    sys.exit(0)
+
+
+if __name__ == "__main__":
+    main()

.github/workflows/check-labels.yml

@@ -0,0 +1,54 @@
+name: Check Labels
+
+on:
+  # We need pull_request_target to be able to post comments on PRs from forks.
+  # Only allow pull_request_target when merging to main, not some historical branch.
+  #
+  # Make sure to don't introduce explicit checking out and installing/running
+  # untrusted user code into this workflow!
+  pull_request_target:
+    types: [opened, synchronize, reopened, labeled, unlabeled]
+    branches: [main]
+
+  # To check labels on ghstack PRs.
+  # Note: as pull_request doesn't trigger on PRs targeting main,
+  # to test changes to the workflow itself one needs to create
+  # a PR that targets a gh/**/base branch.
+  pull_request:
+    types: [opened, synchronize, reopened, labeled, unlabeled]
+    branches: [gh/**/base]
+
+  workflow_dispatch:
+    inputs:
+      pr_number:
+        description: 'PR number to check labels for'
+        required: true
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.sha }}-${{ github.event_name == 'workflow_dispatch' }}
+  cancel-in-progress: true
+
+jobs:
+  check-labels:
+    permissions:
+      contents: read
+      pull-requests: write
+    name: Check labels
+    if: github.repository_owner == 'pytorch'
+    runs-on: ubuntu-22.04
+    steps:
+      - uses: actions/checkout@v3
+	with:
+	  fetch-depth: '0'
+
+      - uses: actions/setup-python@v4
+	with:
+	  python-version: '3.10'
+
+      - name: Check labels
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          PR_NUM: ${{ github.event.number || github.event.inputs.pr_number }}
+        run: |
+          set -ex
+          python3 .github/scripts/check_labels.py --exit-non-zero "${PR_NUM}"