userbar render function should not call context processor(s) (#12411)

Fixes #12410

CHANGELOG.txt

@@ -42,6 +42,7 @@ Changelog
  * Fix: On "move page" bulk action, do not prefill the destination with the root page (Stefan Hammer)
  * Fix: Ensure the default preferred language respects the `WAGTAILADMIN_PERMITTED_LANGUAGES` setting (Sébastien Corbin)
  * Fix: Ensure there is consistent padding in homepage panels table headers (Aditya (megatrron))
+ * Fix: Prevent redundant calls to context processors when rendering userbar (Ihor Marhitych)
  * Docs: Add missing `django.contrib.admin` to list of apps in "add to Django project" guide (Mohamed Rabiaa)
  * Docs: Add tutorial on deploying on Ubuntu to third-party tutorials (Mohammad Fathi Rahman)
  * Docs: Document that request_or_site is optional on BaseGenericSetting.load (Matt Westcott)

docs/releases/7.0.md

@@ -66,6 +66,7 @@ We have a new pagination interface for all listing views and most choosers, incl
  * On "move page" bulk action, do not prefill the destination with the root page (Stefan Hammer)
  * Ensure the default preferred language respects the `WAGTAILADMIN_PERMITTED_LANGUAGES` setting (Sébastien Corbin)
  * Ensure there is consistent padding in homepage panels table headers (Aditya (megatrron))
+ * Prevent redundant calls to context processors when rendering userbar (Ihor Marhitych)
 
 ### Documentation
 

wagtail/admin/tests/test_userbar.py

@@ -11,6 +11,7 @@ from wagtail import hooks
 from wagtail.admin.userbar import AccessibilityItem
 from wagtail.coreutils import get_dummy_request
 from wagtail.models import PAGE_TEMPLATE_VAR, Locale, Page, Site
+from wagtail.test.context_processors import get_call_count, reset_call_count
 from wagtail.test.testapp.models import BusinessChild, BusinessIndex, SimplePage
 from wagtail.test.utils import WagtailTestUtils
 from wagtail.users.models import UserProfile
@@ -444,11 +445,13 @@ class TestUserbarInPageServe(WagtailTestUtils, TestCase):
         self.homepage.add_child(instance=self.page)
 
     def test_userbar_rendered(self):
+        reset_call_count()
         response = self.page.serve(self.request)
         response.render()
 
         self.assertEqual(response.status_code, 200)
         self.assertContains(response, '<template id="wagtail-userbar-template">')
+        self.assertEqual(get_call_count(), 1)
 
     def test_userbar_anonymous_user_cannot_see(self):
         self.request.user = AnonymousUser()

wagtail/admin/userbar.py

@@ -15,9 +15,7 @@ class BaseItem:
         return {"self": self, "request": request}
 
     def render(self, request):
-        return render_to_string(
-            self.template, self.get_context_data(request), request=request
-        )
+        return render_to_string(self.template, self.get_context_data(request))
 
 
 class AdminItem(BaseItem):

wagtail/test/context_processors.py

@@ -7,3 +7,22 @@ def do_not_use_static_url(request):
     return {
         "STATIC_URL": lambda: exception(),
     }
+
+
+CALL_COUNT = 0
+
+
+def count_calls(request):
+    global CALL_COUNT
+    CALL_COUNT += 1
+    return {}
+
+
+def get_call_count():
+    global CALL_COUNT
+    return CALL_COUNT
+
+
+def reset_call_count():
+    global CALL_COUNT
+    CALL_COUNT = 0

wagtail/test/settings.py

@@ -101,6 +101,7 @@ TEMPLATES = [
                 "django.template.context_processors.request",
                 "wagtail.test.context_processors.do_not_use_static_url",
                 "wagtail.contrib.settings.context_processors.settings",
+                "wagtail.test.context_processors.count_calls",
             ],
             "debug": True,  # required in order to catch template errors
         },