Raise warning if there are revisions for moderation

wagtail/admin/tests/test_moderation_list.py

@@ -5,11 +5,18 @@ from django.urls import reverse
 from wagtail.models import GroupPagePermission, Page
 from wagtail.test.testapp.models import SimplePage
 from wagtail.test.utils import WagtailTestUtils
+from wagtail.utils.deprecation import RemovedInWagtail60Warning
 
 
 class TestModerationList(WagtailTestUtils, TestCase):
     """Test moderation list rendered by `wagtailadmin_home` view"""
 
+    # RemovedInWagtail60Warning
+    # Remove this test class when the deprecation period for the legacy
+    # moderation system ends.
+    # For workflows, this has been covered in
+    # wagtail.admin.tests.test_workflows.TestDashboardWithPages
+
     def setUp(self):
         # Create a submitter
         submitter = self.create_user(
@@ -70,7 +77,15 @@ class TestModerationList(WagtailTestUtils, TestCase):
         self.login(moderator)
 
     def get(self):
-        return self.client.get(reverse("wagtailadmin_home"))
+        with self.assertWarnsMessage(
+            RemovedInWagtail60Warning,
+            "You have pages undergoing moderation in the legacy moderation system. "
+            "Complete the moderation of these pages before upgrading Wagtail. "
+            "Support for the legacy moderation system will be completely removed "
+            "in a future release. For more details, refer to "
+            "https://docs.wagtail.org/en/stable/releases/2.10.html#move-to-new-configurable-moderation-system-workflow",
+        ):
+            return self.client.get(reverse("wagtailadmin_home"))
 
     def test_edit_page(self):
         # Login as moderator

wagtail/admin/views/home.py

@@ -1,5 +1,6 @@
 import itertools
 import re
+import warnings
 from typing import Any, Mapping, Union
 
 from django.conf import settings
@@ -27,6 +28,7 @@ from wagtail.models import (
     get_default_page_content_type,
 )
 from wagtail.permission_policies.pages import PagePermissionPolicy
+from wagtail.utils.deprecation import RemovedInWagtail60Warning
 
 User = get_user_model()
 
@@ -100,12 +102,22 @@ class PagesForModerationPanel(Component):
     def get_context_data(self, parent_context):
         request = parent_context["request"]
         context = super().get_context_data(parent_context)
-        context["page_revisions_for_moderation"] = (
+        revisions = (
             PagePermissionPolicy()
             .revisions_for_moderation(request.user)
             .select_related("user")
             .order_by("-created_at")
         )
+        if revisions:
+            warnings.warn(
+                "You have pages undergoing moderation in the legacy moderation system. "
+                "Complete the moderation of these pages before upgrading Wagtail. "
+                "Support for the legacy moderation system will be completely removed "
+                "in a future release. For more details, refer to "
+                "https://docs.wagtail.org/en/stable/releases/2.10.html#move-to-new-configurable-moderation-system-workflow",
+                RemovedInWagtail60Warning,
+            )
+        context["page_revisions_for_moderation"] = revisions
         context["request"] = request
         context["csrf_token"] = parent_context["csrf_token"]
         return context