Propagate labels from the issue to the PR (#2357)

* Add a GH action that propagates labels from an issue with docathon label to the PR that references it.
---------

Co-authored-by: Nikita Shulga <nshulga@meta.com>

Author: Svetlana Karslioglu

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

@@ -0,0 +1,43 @@
+import os
+from github import Github
+import sys
+import re
+
+def main():
+    token = os.environ.get('GITHUB_TOKEN')
+
+    repo_owner = "pytorch"
+    repo_name = "tutorials"
+    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
+
+    # get issue number from the PR body
+    if not re.search(r'#\d{1,5}', pull_request_body):
+        print("The pull request does not mention an issue.")
+        return
+    issue_number = int(re.findall(r'#(\d{1,5})', pull_request_body)[0])
+    issue = repo.get_issue(issue_number)
+    issue_labels = issue.labels
+    docathon_label_present = any(label.name == 'docathon-h1-2023' 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-h1-2023' label is not present in the issue.")
+        return    
+    pull_request_labels = pull_request.get_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_labels]
+    if not labels_to_add:
+        print("The pull request already has the same labels.")
+        return
+    pull_request.set_labels(*labels_to_add)
+    print("Labels added to the pull request!")
+        
+
+           
+if __name__  == "__main__":
+    main()

.github/workflows/docathon-label-sync.yml

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+name: Docathon Labels Sync
+
+on:
+  pull_request:
+    types: [opened, synchronize, edited]
+
+jobs:
+  check-labels:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Check if PR mentions an issue and get labels
+        uses: actions/checkout@v2
+        with:
+          fetch-depth: 0
+      - name: Set up Python
+        uses: actions/setup-python@v2
+        with:
+          python-version: 3.x
+      - name: Install dependencies
+        run: |
+          pip install requests
+          pip install PyGithub
+      - name: Run Python script
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: python ./.github/scripts/docathon-label-sync.py ${{ github.event.pull_request.number }}