fix: allows taxonomy list to "filter by org" even if org does not exist (#33686)

If the user requests the taxonomies linked to a non-existent org, then
we still want to see the non-org taxonomies.

openedx/core/djangoapps/content_tagging/rest_api/v1/serializers.py

@@ -4,6 +4,7 @@ API Serializers for content tagging org
 
 from __future__ import annotations
 
+from django.core.exceptions import ObjectDoesNotExist
 from rest_framework import serializers, fields
 
 from openedx_tagging.core.tagging.rest_api.v1.serializers import (
@@ -14,12 +15,33 @@ from openedx_tagging.core.tagging.rest_api.v1.serializers import (
 from organizations.models import Organization
 
 
+class OptionalSlugRelatedField(serializers.SlugRelatedField):
+    """
+    Modifies the DRF serializer SlugRelatedField.
+
+    Non-existent slug values are represented internally as an empty queryset, instead of throwing a validation error.
+    """
+
+    def to_internal_value(self, data):
+        """
+        Returns the object related to the given slug value, or an empty queryset if not found.
+        """
+
+        queryset = self.get_queryset()
+        try:
+            return queryset.get(**{self.slug_field: data})
+        except ObjectDoesNotExist:
+            return queryset.none()
+        except (TypeError, ValueError):
+            self.fail('invalid')
+
+
 class TaxonomyOrgListQueryParamsSerializer(TaxonomyListQueryParamsSerializer):
     """
     Serializer for the query params for the GET view
     """
 
-    org: fields.Field = serializers.SlugRelatedField(
+    org: fields.Field = OptionalSlugRelatedField(
         slug_field="short_name",
         queryset=Organization.objects.all(),
         required=False,

openedx/core/djangoapps/content_tagging/rest_api/v1/tests/test_views.py

@@ -343,6 +343,8 @@ class TestTaxonomyListCreateViewSet(TestTaxonomyObjectsMixin, APITestCase):
         ("orgA", ["st1", "st2", "t1", "t2", "tA1", "tA2", "tBA1", "tBA2"]),
         ("orgB", ["st1", "st2", "t1", "t2", "tB1", "tB2", "tBA1", "tBA2"]),
         ("orgX", ["st1", "st2", "t1", "t2"]),
+        # Non-existent orgs are ignored
+        ("invalidOrg", ["st1", "st2", "t1", "t2"]),
     )
     @ddt.unpack
     def test_list_taxonomy_org_filter(self, org_parameter: str, expected_taxonomies: list[str]) -> None:
@@ -355,20 +357,6 @@ class TestTaxonomyListCreateViewSet(TestTaxonomyObjectsMixin, APITestCase):
             expected_taxonomies=expected_taxonomies,
         )
 
-    def test_list_taxonomy_invalid_org(self) -> None:
-        """
-        Tests that using an invalid org in the filter will raise BAD_REQUEST
-        """
-        url = TAXONOMY_ORG_LIST_URL
-
-        self.client.force_authenticate(user=self.staff)
-
-        query_params = {"org": "invalidOrg"}
-
-        response = self.client.get(url, query_params, format="json")
-
-        assert response.status_code == status.HTTP_400_BAD_REQUEST
-
     @ddt.data(
         ("user", (), None),
         ("staffA", ["tA2", "tBA1", "tBA2"], None),

openedx/core/djangoapps/content_tagging/rest_api/v1/views.py

@@ -52,8 +52,10 @@ class TaxonomyOrgView(TaxonomyView):
         query_params = TaxonomyOrgListQueryParamsSerializer(data=self.request.query_params.dict())
         query_params.is_valid(raise_exception=True)
         enabled = query_params.validated_data.get("enabled", None)
+
+        # If org filtering was requested, then use it, even if the org is invalid/None
         org = query_params.validated_data.get("org", None)
-        if org:
+        if "org" in query_params.validated_data:
             queryset = get_taxonomies_for_org(enabled, org)
         else:
             queryset = get_taxonomies(enabled)