Ensured that no fields are returned when sparse fields is set to an empty value (#1240)

Author: sliverc

Diff for: CHANGELOG.md

@@ -13,6 +13,7 @@ any parts of the framework not mentioned in the documentation should generally b
 ### Fixed
 
 * Re-enabled overwriting of url field (regression since 7.0.0)
+* Ensured that no fields are rendered when sparse fields is set to an empty value. (regression since 7.0.0)
 
 ## [7.0.1] - 2024-06-06
 

Diff for: rest_framework_json_api/renderers.py

@@ -439,7 +439,7 @@ def _filter_sparse_fields(cls, serializer, fields, resource_name):
             sparse_fieldset_value = request.query_params.get(
                 sparse_fieldset_query_param
             )
-            if sparse_fieldset_value:
+            if sparse_fieldset_value is not None:
                 sparse_fields = sparse_fieldset_value.split(",")
                 return {
                     field_name: field

Diff for: rest_framework_json_api/serializers.py

@@ -89,7 +89,7 @@ def _readable_fields(self):
                 sparse_fieldset_value = request.query_params.get(
                     sparse_fieldset_query_param
                 )
-                if sparse_fieldset_value:
+                if sparse_fieldset_value is not None:
                     sparse_fields = sparse_fieldset_value.split(",")
                     return (
                         field

Diff for: tests/test_views.py

@@ -219,6 +219,19 @@ def test_list_allow_overwiritng_url_with_sparse_fields(self, client, url_instanc
             }
         ]
 
+    @pytest.mark.urls(__name__)
+    def test_list_with_sparse_fields_empty_value(self, client, model):
+        url = reverse("basic-model-list")
+        response = client.get(url, data={"fields[BasicModel]": ""})
+        assert response.status_code == status.HTTP_200_OK
+        data = response.json()["data"]
+        assert data == [
+            {
+                "type": "BasicModel",
+                "id": str(model.pk),
+            }
+        ]
+
     @pytest.mark.urls(__name__)
     def test_retrieve(self, client, model):
         url = reverse("basic-model-detail", kwargs={"pk": model.pk})