♻️(backend) include sub documents in the favorite_list route

The favorite_list route was returning all the favorite with depth=0. We
also want to see favorited document with a depth > 0

src/backend/core/api/viewsets.py

@@ -628,12 +628,29 @@ class DocumentViewSet(
         """Get list of favorite documents for the current user."""
         user = request.user
 
+        queryset = self.get_queryset()
+
+        # Among the results, we may have documents that are ancestors/descendants
+        # of each other. In this case we want to keep only the highest ancestors.
+        root_paths = utils.filter_root_paths(
+            queryset.order_by("path").values_list("path", flat=True),
+            skip_sorting=True,
+        )
+
+        path_list = db.Q()
+        for path in root_paths:
+            path_list |= db.Q(path__startswith=path)
+
         favorite_documents_ids = models.DocumentFavorite.objects.filter(
             user=user
         ).values_list("document_id", flat=True)
 
-        queryset = self.filter_queryset(self.get_queryset())
+        queryset = self.queryset.filter(path_list)
         queryset = queryset.filter(id__in=favorite_documents_ids)
+        queryset = queryset.annotate_user_roles(user)
+        queryset = queryset.annotate(
+            is_favorite=db.Value(True, output_field=db.BooleanField())
+        )
         return self.get_response_for_queryset(queryset)
 
     @drf.decorators.action(

src/backend/core/tests/documents/test_api_documents_favorite_list.py

@@ -83,3 +83,34 @@ def test_api_document_favorite_list_authenticated_with_favorite():
             }
         ],
     }
+
+
+def test_api_document_favorite_list_with_favorite_children():
+    """Authenticated users should receive their favorite documents, including children."""
+
+    user = factories.UserFactory()
+    client = APIClient()
+    client.force_login(user)
+
+    root = factories.DocumentFactory(creator=user, users=[user])
+    children = factories.DocumentFactory.create_batch(
+        2, parent=root, favorited_by=[user]
+    )
+
+    access = factories.UserDocumentAccessFactory(
+        user=user, role=models.RoleChoices.READER, document__favorited_by=[user]
+    )
+
+    other_root = factories.DocumentFactory(creator=user, users=[user])
+    factories.DocumentFactory.create_batch(2, parent=other_root)
+
+    response = client.get("/api/v1.0/documents/favorite_list/")
+
+    assert response.status_code == 200
+    assert response.json()["count"] == 3
+
+    content = response.json()["results"]
+
+    assert content[0]["id"] == str(children[0].id)
+    assert content[1]["id"] == str(children[1].id)
+    assert content[2]["id"] == str(access.document.id)