fix: re-fetch PR details in enricher to avoid stale requested_reviewers

CHANGELOG.md

@@ -8,6 +8,15 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
 
 ### Fixed
 
+- **Stale PR data in CODEOWNERS checks** -- `PullRequestEnricher` now
+  re-fetches PR details via `GET /repos/:owner/:repo/pulls/:num` before
+  building `event_data`, replacing the webhook payload's `requested_reviewers`
+  (and other point-in-time fields) with the current state. Fixes a race where
+  a `synchronize` webhook processed just before a `review_requested` webhook
+  would see a stale `requested_reviewers` list and incorrectly flag
+  `PathHasCodeOwnerCondition` / `RequireCodeOwnerReviewersCondition`
+  violations. Falls back to the webhook payload if the refresh fails.
+
 - **`FilePatternCondition._get_changed_files` implementation** -- Replaced
   stub that always returned `[]` with a working implementation that extracts
   file paths from enriched PR data (`changed_files` list of dicts or plain

src/event_processors/pull_request/enricher.py

@@ -55,6 +55,16 @@ async def enrich_event_data(self, task: Any, github_token: str) -> dict[str, Any
         repo_full_name = getattr(task, "repo_full_name", "")
         installation_id = getattr(task, "installation_id", 0)
 
+        # the current state, not the stale webhook snapshot (webhooks for
+        # synchronize + review_requested can race).
+        if pr_number and repo_full_name:
+            try:
+                fresh_pr = await self.github_client.get_pull_request(repo_full_name, pr_number, installation_id)
+                if fresh_pr:
+                    pr_data = fresh_pr
+            except Exception as e:
+                logger.warning(f"Could not refresh PR #{pr_number} details: {e}")
+
         # Base event data
         event_data = {
             "pull_request_details": pr_data,

tests/unit/event_processors/pull_request/test_enricher.py

@@ -45,6 +45,7 @@ async def test_fetch_api_data_success(enricher, mock_github_client):
 
 @pytest.mark.asyncio
 async def test_enrich_event_data(enricher, mock_task, mock_github_client):
+    mock_github_client.get_pull_request.return_value = {"number": 1, "user": {"login": "author"}}
     mock_github_client.get_pull_request_reviews.return_value = []
     mock_github_client.get_pull_request_files.return_value = [
         {"filename": "test.py", "status": "added", "additions": 10, "deletions": 0, "patch": "+print('hello')"}
@@ -61,6 +62,53 @@ async def test_enrich_event_data(enricher, mock_task, mock_github_client):
     assert "diff_summary" in event_data
 
 
+@pytest.mark.asyncio
+async def test_enrich_event_data_refreshes_pr_details(enricher, mock_task, mock_github_client):
+    """Stale webhook requested_reviewers is replaced by fresh PR details from the API.
+
+    Simulates the synchronize+review_requested race: the webhook payload's
+    requested_reviewers is empty, but a fresh GET /pulls/:num shows alice was
+    requested. The enricher must surface the fresh state so CODEOWNERS rules
+    don't false-positive.
+    """
+    mock_task.payload["pull_request"] = {
+        "number": 1,
+        "user": {"login": "author"},
+        "requested_reviewers": [],
+        "requested_teams": [],
+    }
+    mock_github_client.get_pull_request.return_value = {
+        "number": 1,
+        "user": {"login": "author"},
+        "requested_reviewers": [{"login": "alice"}],
+        "requested_teams": [],
+    }
+    mock_github_client.get_pull_request_reviews.return_value = []
+    mock_github_client.get_pull_request_files.return_value = []
+
+    event_data = await enricher.enrich_event_data(mock_task, "fake_token")
+
+    assert event_data["pull_request_details"]["requested_reviewers"] == [{"login": "alice"}]
+    mock_github_client.get_pull_request.assert_called_once_with("owner/repo", 1, 12345)
+
+
+@pytest.mark.asyncio
+async def test_enrich_event_data_falls_back_to_webhook_pr_when_refresh_fails(enricher, mock_task, mock_github_client):
+    """If the refresh API call fails or returns None, the webhook payload PR data is kept."""
+    mock_task.payload["pull_request"] = {
+        "number": 1,
+        "user": {"login": "author"},
+        "requested_reviewers": [{"login": "bob"}],
+    }
+    mock_github_client.get_pull_request.return_value = None
+    mock_github_client.get_pull_request_reviews.return_value = []
+    mock_github_client.get_pull_request_files.return_value = []
+
+    event_data = await enricher.enrich_event_data(mock_task, "fake_token")
+
+    assert event_data["pull_request_details"]["requested_reviewers"] == [{"login": "bob"}]
+
+
 @pytest.mark.asyncio
 async def test_fetch_acknowledgments(enricher, mock_github_client):
     mock_github_client.get_issue_comments.return_value = [