Fix workflow for pinging maintainers in case of unlabeled PRs (#4021)

* add additional workflow trigger

* [skip ci] fix name of script for PR label processing (#4013)

* trigger CI

* fix workflow in case commit has no associated PR

* [skip CI] test PR for label-checking workflow (#4015)

* [skip CI] fix PR labels processing logic (#4016)

* [skip CI] try fix trigger for unlabeled PR pings (#4017)

* [skip CI] remove quotes around users ping (#4018)

* [skip CI] cleanup PR labeling workflow (#4019)

* [skip CI] fix ping message for unlabeled PRs (#4020)

* cleanup

.github/process_pr.py → .github/process_commit.py

-import json
+"""
+This script finds all responsible users for labeling a PR by a commit SHA. It is used by the workflow in
+'.github/workflows/pr-labels.yml'. If there exists no PR associated with the commit or the PR is properly labeled,
+this script is a no-op.
+"""
+
 import sys
-from typing import Any, Dict, Set, Tuple
+from typing import Any, Optional, Set, Tuple
 
 import requests
 
-# If the PR has any of these labels, we mark it as properly labeled.
+# If the PR has any of these labels, we accept it as properly labeled.
 REQUIRED_LABELS = {
     "new feature",
     "bug",
@@ -33,34 +38,35 @@ REQUIRED_LABELS = {
 }
 
 
-def main(commit_hash: str) -> Dict[str, Any]:
+def find_responsible_users(commit_hash: str) -> Set[str]:
     pr_number = get_pr_number(commit_hash)
+    if not pr_number:
+        return set()
+
     merger, labels = get_pr_merger_and_labels(pr_number)
     is_properly_labeled = bool(REQUIRED_LABELS.intersection(labels))
-    if not is_properly_labeled:
-        users = {merger, *get_pr_reviewers(pr_number)}
-    else:
-        users = ()
-    return dict(
-        is_properly_labeled=is_properly_labeled,
-        responsible_users=", ".join(sorted([f"@{user}" for user in users])),
-    )
+    if is_properly_labeled:
+        return set()
+
+    return {merger, *get_pr_reviewers(pr_number)}
 
 
-def _query_torchvision(cmd: str, *, accept) -> Any:
+def query_torchvision(cmd: str, *, accept) -> Any:
     response = requests.get(f"https://api.github.com/repos/pytorch/vision/{cmd}", headers=dict(Accept=accept))
     return response.json()
 
 
-def get_pr_number(commit_hash: str) -> int:
+def get_pr_number(commit_hash: str) -> Optional[int]:
     # See https://docs.github.com/en/rest/reference/repos#list-pull-requests-associated-with-a-commit
-    data = _query_torchvision(f"commits/{commit_hash}/pulls", accept="application/vnd.github.groot-preview+json")
+    data = query_torchvision(f"commits/{commit_hash}/pulls", accept="application/vnd.github.groot-preview+json")
+    if not data:
+        return None
     return data[0]["number"]
 
 
 def get_pr_merger_and_labels(pr_number: int) -> Tuple[str, Set[str]]:
     # See https://docs.github.com/en/rest/reference/pulls#get-a-pull-request
-    data = _query_torchvision(f"pulls/{pr_number}", accept="application/vnd.github.v3+json")
+    data = query_torchvision(f"pulls/{pr_number}", accept="application/vnd.github.v3+json")
     merger = data["merged_by"]["login"]
     labels = {label["name"] for label in data["labels"]}
     return merger, labels
@@ -68,11 +74,11 @@ def get_pr_merger_and_labels(pr_number: int) -> Tuple[str, Set[str]]:
 
 def get_pr_reviewers(pr_number: int) -> Set[str]:
     # See https://docs.github.com/en/rest/reference/pulls#list-reviews-for-a-pull-request
-    data = _query_torchvision(f"pulls/{pr_number}/reviews", accept="application/vnd.github.v3+json")
+    data = query_torchvision(f"pulls/{pr_number}/reviews", accept="application/vnd.github.v3+json")
     return {review["user"]["login"] for review in data if review["state"] == "APPROVED"}
 
 
 if __name__ == "__main__":
     commit_hash = sys.argv[1]
-    data = main(commit_hash)
-    print(json.dumps(data))
+    users = find_responsible_users(commit_hash)
+    print(", ".join(sorted([f"@{user}" for user in users])))

.github/workflows/pr-labels.yml

@@ -19,21 +19,17 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v2
 
-      - name: Process PR associated with current commit
-        id: data
-        run: |
-          DATA=$(python .github/foo.py ${{ github.sha }})
-          jq . <<< $DATA
-          echo "::set-output name=is_properly_labeled::$(jq .is_properly_labeled <<< $DATA)"
-          echo "::set-output name=responsible_users::$(jq .responsible_users <<< $DATA)"
-
-      - name: Ping responsible users
-        if: ${{ !steps.data.outputs.is_properly_labeled }}
+      - name: Process commit and find users responsible for labeling
+        id: commit
+        run: echo "::set-output name=responsible_users::$(python .github/process_commit.py ${{ github.sha }})"
+
+      - name: Ping users responsible for labeling if necessary
+        if: ${{ steps.commit.outputs.responsible_users != '' }}
         uses: mshick/add-pr-comment@v1
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
         with:
           message: |
-            Hey ${{ steps.data.outputs.responsible_users }}!
+            Hey ${{ steps.commit.outputs.responsible_users }}!
 
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