feat(dashboards): Backfill positions when requested in starred endpoint (#93920)

If any of the dashboards that are requested have position unset, then
take the order and commit them so the position is backfilled

There shouldn't be a scenario where there are positioned dashboards and
unpositioned dashboards, but the test case shows that it can be handled.
This is meant to fill in data for a user's first visit. When we see that
the data is all backfilled we can remove the code related to this check.

Author: narsaynorath

src/sentry/api/endpoints/organization_dashboards_starred.py

@@ -46,6 +46,15 @@ def get(self, request: Request, organization: Organization) -> Response:
             organization=organization, user_id=request.user.id
         ).select_related("dashboard")
 
+        if favorites.filter(position__isnull=True).exists():
+            # Commit the order of the dashboards of this current response if there are any
+            # that don't have a position assigned
+            DashboardFavoriteUser.objects.reorder_favorite_dashboards(
+                organization=organization,
+                user_id=request.user.id,
+                new_dashboard_positions=[favorite.dashboard.id for favorite in favorites],
+            )
+
         def data_fn(offset, limit):
             return [favorite.dashboard for favorite in favorites[offset : offset + limit]]
 

tests/sentry/api/endpoints/test_organization_dashboards_starred.py

@@ -47,6 +47,41 @@ def test_get_favorite_dashboards(self):
             self.dashboard_1.id,
         ]
 
+    def test_get_request_assigns_positions_if_missing(self):
+        self.create_dashboard_favorite(self.dashboard_1, self.user, self.organization, None)
+        self.create_dashboard_favorite(self.dashboard_2, self.user, self.organization, 2)
+        self.create_dashboard_favorite(self.dashboard_3, self.user, self.organization, None)
+
+        response = self.do_request("get", self.url)
+        assert response.status_code == 200
+        assert len(response.data) == 3
+        assert [int(dashboard["id"]) for dashboard in response.data] == [
+            self.dashboard_2.id,
+            self.dashboard_1.id,
+            self.dashboard_3.id,
+        ]
+
+        assert (
+            DashboardFavoriteUser.objects.get(
+                organization=self.organization, user_id=self.user.id, dashboard=self.dashboard_1
+            ).position
+            == 1
+        )
+        assert (
+            DashboardFavoriteUser.objects.get(
+                organization=self.organization, user_id=self.user.id, dashboard=self.dashboard_3
+            ).position
+            == 2
+        )
+
+        # Positioned dashboards are at the top of the list in this operation
+        assert (
+            DashboardFavoriteUser.objects.get(
+                organization=self.organization, user_id=self.user.id, dashboard=self.dashboard_2
+            ).position
+            == 0
+        )
+
 
 class OrganizationDashboardsStarredOrderTest(StarredDashboardTestCase):
     def setUp(self):