Stop emails from breaking when WAGTAILADMIN_BASE_URL is absent

In this case, workflow notification emails can't include the full URL (because they're triggered from a signal, where we don't have access to a request object) but we don't want them to break outright.

fixes #8582

wagtail/admin/templatetags/wagtailadmin_tags.py

@@ -228,9 +228,9 @@ def usage_count_enabled():
     return getattr(settings, "WAGTAIL_USAGE_COUNT_ENABLED", False)
 
 
-@register.simple_tag(takes_context=True)
-def base_url_setting(context=None):
-    return get_admin_base_url(context=context)
+@register.simple_tag
+def base_url_setting():
+    return get_admin_base_url()
 
 
 @register.simple_tag

wagtail/admin/tests/test_password_reset.py

@@ -66,6 +66,14 @@ class TestUserPasswordReset(TestCase, WagtailTestUtils):
         self.assertEqual(len(mail.outbox), 1)
         self.assertIn("mysite.com", mail.outbox[0].body)
 
+    @override_settings(ROOT_URLCONF="wagtail.admin.urls", WAGTAILADMIN_BASE_URL=None)
+    def test_email_without_base_url(self):
+        response = self.client.post(
+            reverse("wagtailadmin_password_reset"), {"email": "siteeditor@example.com"}
+        )
+        self.assertEqual(response.status_code, 302)
+        self.assertEqual(len(mail.outbox), 1)
+
     @unittest.skipUnless(
         settings.AUTH_USER_MODEL == "customuser.CustomUser",
         "only applicable to CustomUser",

wagtail/admin/tests/test_workflows.py

@@ -925,6 +925,7 @@ class TestSubmitToWorkflow(TestCase, WagtailTestUtils):
         )
         self.assertNotContains(response, "Draft")
 
+    @override_settings(WAGTAILADMIN_BASE_URL="http://admin.example.com")
     def test_submit_sends_mail(self):
         self.submit()
         # 3 emails sent:
@@ -948,6 +949,35 @@ class TestSubmitToWorkflow(TestCase, WagtailTestUtils):
             'The page "Hello world! (simple page)" has been submitted for moderation to workflow "test_workflow" by submitter',
             workflow_message.body,
         )
+        self.assertIn("http://admin.example.com/admin/", workflow_message.body)
+
+    @override_settings(WAGTAILADMIN_BASE_URL=None)
+    def test_submit_sends_mail_without_base_url(self):
+        # With a missing WAGTAILADMIN_BASE_URL setting, we won't be able to construct absolute URLs
+        # for the email, but we don't want it to fail outright either
+
+        self.submit()
+        # 3 emails sent:
+        # - to moderator - submitted for approval in moderation stage test_task_1
+        # - to superuser - submitted for approval in moderation stage test_task_1
+        # - to superuser - submitted to workflow test_workflow
+        self.assertEqual(len(mail.outbox), 3)
+
+        # the 'submitted to workflow' email should include the submitter's name
+        workflow_message = None
+        for msg in mail.outbox:
+            if (
+                msg.subject
+                == 'The page "Hello world! (simple page)" has been submitted to workflow "test_workflow"'
+            ):
+                workflow_message = msg
+                break
+
+        self.assertTrue(workflow_message)
+        self.assertIn(
+            'The page "Hello world! (simple page)" has been submitted for moderation to workflow "test_workflow" by submitter',
+            workflow_message.body,
+        )
 
     @mock.patch.object(
         EmailMultiAlternatives, "send", side_effect=IOError("Server down")

wagtail/admin/utils.py

@@ -5,12 +5,10 @@ from django.conf import settings
 from wagtail.utils.deprecation import RemovedInWagtail50Warning
 
 
-def get_admin_base_url(context=None):
+def get_admin_base_url():
     """
     Gets the base URL for the wagtail admin site. This is set in `settings.WAGTAILADMIN_BASE_URL`,
     which was previously `settings.BASE_URL`.
-    If setting is omitted and this is called in a request context, falls back to
-    `request.site.root_url` or next the host_name of the request.
     """
 
     admin_base_url = getattr(settings, "WAGTAILADMIN_BASE_URL", None)
@@ -21,14 +19,4 @@ def get_admin_base_url(context=None):
         )
         admin_base_url = settings.BASE_URL
 
-    if admin_base_url is None and context is not None:
-        request = context["request"]
-        admin_base_url = getattr(request.site, "root_url", None)
-        if admin_base_url is None:
-            admin_base_url = request.get_host()
-            secure_prefix = "http"
-            if request.is_secure():
-                secure_prefix = "https"
-            admin_base_url = secure_prefix + "://" + admin_base_url
-
     return admin_base_url