⚡️ Disable pagination when requesting form definitions in the admin

src/openforms/forms/api/pagination.py

@@ -0,0 +1,19 @@
+from rest_framework import pagination
+
+
+class FormDefinitionPagination(pagination.PageNumberPagination):
+    """A page number pagination that will be disabled if the specific query parameter
+    for page size is set to 0.
+    """
+
+    page_size = 25
+    page_size_query_param = "page_size"
+    max_page_size = None
+
+    def get_page_size(self, request) -> int | None:
+        if (
+            self.page_size_query_param
+            and request.query_params.get(self.page_query_param) == 0
+        ):
+            return None
+        return super().get_page_size(request)

src/openforms/forms/api/viewsets.py

@@ -18,7 +18,6 @@
 from rest_framework.request import Request
 from rest_framework.response import Response
 
-from openforms.api.pagination import PageNumberPagination
 from openforms.api.serializers import ExceptionSerializer, ValidationErrorSerializer
 from openforms.translations.utils import set_language_cookie
 from openforms.utils.patches.rest_framework_nested.viewsets import NestedViewSetMixin
@@ -32,6 +31,7 @@
 from .datastructures import FormVariableWrapper
 from .documentation import get_admin_fields_markdown
 from .filters import FormDefinitionFilter, FormVariableFilter
+from .pagination import FormDefinitionPagination
 from .parsers import (
     FormCamelCaseJSONParser,
     FormVariableJSONParser,
@@ -169,7 +169,7 @@ class FormDefinitionViewSet(viewsets.ModelViewSet):
     renderer_classes = (IgnoreConfigurationFieldCamelCaseJSONRenderer,)
     queryset = FormDefinition.objects.order_by("slug")
     serializer_class = FormDefinitionSerializer
-    pagination_class = PageNumberPagination
+    pagination_class = FormDefinitionPagination
     lookup_field = "uuid"
     # anonymous clients must be able to get the form definitions in the browser
     # The DRF settings apply some default throttling to mitigate abuse

src/openforms/forms/tests/test_api_formdefinition.py

@@ -39,6 +39,29 @@ def test_list(self):
 
         self.assertEqual(response.status_code, status.HTTP_403_FORBIDDEN)
 
+    def test_list_pagination(self):
+        user = StaffUserFactory.create(user_permissions=["change_form"])
+        self.client.force_authenticate(user=user)
+
+        FormDefinitionFactory.create_batch(100)
+
+        url = reverse("api:formdefinition-list")
+
+        with self.subTest("no pagination"):
+            response = self.client.get(url, {"page_size": "0"}, format="json")
+            self.assertEqual(response.status_code, status.HTTP_200_OK)
+            self.assertEqual(len(response.json()["results"]), 100)
+
+        with self.subTest("default pagination"):
+            response = self.client.get(url, format="json")
+            self.assertEqual(response.status_code, status.HTTP_200_OK)
+            self.assertEqual(len(response.json()["results"]), 25)
+
+        with self.subTest("explicit pagination"):
+            response = self.client.get(url, {"page_size": "30"}, format="json")
+            self.assertEqual(response.status_code, status.HTTP_200_OK)
+            self.assertEqual(len(response.json()["results"]), 30)
+
     def test_user_without_permission_cant_update(self):
         user = UserFactory.create()
         self.client.force_authenticate(user=user)

src/openforms/js/components/admin/form_design/form-creation-form.js

@@ -187,7 +187,7 @@ function reducer(draft, action) {
      * Form-level actions
      */
     case 'BACKEND_DATA_LOADED': {
-      const {formData, supportingData} = action.payload;
+      const {supportingData, formData} = action.payload;
       const {form, selectedAuthPlugins, steps, variables, logicRules, priceRules} = formData;
 
       for (const [stateVar, data] of Object.entries(supportingData)) {
@@ -955,7 +955,7 @@ const FormCreationForm = ({formUuid, formUrl, formHistoryUrl}) => {
     {endpoint: PAYMENT_PLUGINS_ENDPOINT, stateVar: 'availablePaymentBackends'},
     {
       endpoint: FORM_DEFINITIONS_ENDPOINT,
-      query: {is_reusable: true, used_in: formUuid || ''},
+      query: {is_reusable: true, used_in: formUuid || '', page_size: 0},
       stateVar: 'formDefinitions',
     },
     {endpoint: REGISTRATION_BACKENDS_ENDPOINT, stateVar: 'availableRegistrationBackends'},