fix(findings): avoid backfill on empty scans (#8183)

api/CHANGELOG.md

@@ -6,6 +6,13 @@ All notable changes to the **Prowler API** are documented in this file.
 
 ---
 
+## [v1.9.1] (Prowler v5.8.1)
+
+### Fixed
+- Scan with no resources will not trigger legacy code for findings metadata [(#8183)](https://github.com/prowler-cloud/prowler/pull/8183)
+
+---
+
 ## [v1.9.0] (Prowler v5.8.0)
 
 ### Added

api/src/backend/api/tests/test_views.py

@@ -3371,6 +3371,61 @@ class TestFindingViewSet:
             ]
         }
 
+    def test_findings_metadata_backfill(
+        self, authenticated_client, scans_fixture, findings_fixture
+    ):
+        scan = scans_fixture[0]
+        scan.unique_resource_count = 1
+        scan.save()
+
+        with patch(
+            "api.v1.views.backfill_scan_resource_summaries_task.apply_async"
+        ) as mock_backfill_task:
+            response = authenticated_client.get(
+                reverse("finding-metadata"),
+                {"filter[scan]": str(scan.id)},
+            )
+        assert response.status_code == status.HTTP_200_OK
+        mock_backfill_task.assert_called()
+
+    def test_findings_metadata_backfill_no_resources(
+        self, authenticated_client, scans_fixture
+    ):
+        scan_id = str(scans_fixture[0].id)
+        with patch(
+            "api.v1.views.backfill_scan_resource_summaries_task.apply_async"
+        ) as mock_backfill_task:
+            response = authenticated_client.get(
+                reverse("finding-metadata"),
+                {"filter[scan]": scan_id},
+            )
+        assert response.status_code == status.HTTP_200_OK
+        mock_backfill_task.assert_not_called()
+
+    def test_findings_metadata_latest_backfill(
+        self, authenticated_client, scans_fixture, findings_fixture
+    ):
+        scan = scans_fixture[0]
+        scan.unique_resource_count = 1
+        scan.save()
+
+        with patch(
+            "api.v1.views.backfill_scan_resource_summaries_task.apply_async"
+        ) as mock_backfill_task:
+            response = authenticated_client.get(reverse("finding-metadata_latest"))
+        assert response.status_code == status.HTTP_200_OK
+        mock_backfill_task.assert_called()
+
+    def test_findings_metadata_latest_backfill_no_resources(
+        self, authenticated_client, scans_fixture
+    ):
+        with patch(
+            "api.v1.views.backfill_scan_resource_summaries_task.apply_async"
+        ) as mock_backfill_task:
+            response = authenticated_client.get(reverse("finding-metadata_latest"))
+        assert response.status_code == status.HTTP_200_OK
+        mock_backfill_task.assert_not_called()
+
     def test_findings_latest(self, authenticated_client, latest_scan_finding):
         response = authenticated_client.get(
             reverse("finding-latest"),

api/src/backend/api/v1/views.py

@@ -2127,9 +2127,12 @@ class FindingViewSet(PaginateByPkMixin, BaseRLSViewSet):
 
         # ToRemove: Temporary fallback mechanism
         if not queryset.exists():
-            scan_ids = Scan.objects.filter(
+            raw_scans_ids = Scan.objects.filter(
                 tenant_id=tenant_id, **scan_based_filters
-            ).values_list("id", flat=True)
+            ).values_list("id", "unique_resource_count")
+            scan_ids = [
+                scan_id for scan_id, count in raw_scans_ids if count and count > 0
+            ]
             for scan_id in scan_ids:
                 backfill_scan_resource_summaries_task.apply_async(
                     kwargs={"tenant_id": tenant_id, "scan_id": scan_id}
@@ -2215,7 +2218,12 @@ class FindingViewSet(PaginateByPkMixin, BaseRLSViewSet):
             .order_by("provider_id", "-inserted_at")
             .distinct("provider_id")
         )
-        latest_scans_ids = list(latest_scans_queryset.values_list("id", flat=True))
+        raw_latest_scans_ids = list(
+            latest_scans_queryset.values_list("id", "unique_resource_count")
+        )
+        latest_scans_ids = [
+            scan_id for scan_id, count in raw_latest_scans_ids if count and count > 0
+        ]
 
         queryset = ResourceScanSummary.objects.filter(
             tenant_id=tenant_id,