From 397edf2ec50fec3603de05d563842f4ff2b1b7f5 Mon Sep 17 00:00:00 2001
From: Matt Westcott <matt@west.co.tt>
Date: Mon, 10 Mar 2025 20:55:50 +0000
Subject: [PATCH] Support deferring validation on StreamField

---
 wagtail/admin/panels/field_panel.py           |  3 +-
 wagtail/admin/tests/pages/test_create_page.py | 63 +++++++++++++++++++
 wagtail/blocks/base.py                        |  3 +
 3 files changed, 68 insertions(+), 1 deletion(-)

diff --git a/wagtail/admin/panels/field_panel.py b/wagtail/admin/panels/field_panel.py
index 02f07b2fcf..3ad200f5f4 100644
--- a/wagtail/admin/panels/field_panel.py
+++ b/wagtail/admin/panels/field_panel.py
@@ -69,7 +69,8 @@ class FieldPanel(Panel):
             else:
                 required_on_save = getattr(db_field, "required_on_save", False) or (
                     db_field.null is False
-                    and db_field.get_internal_type() not in ("CharField", "TextField")
+                    and db_field.get_internal_type()
+                    not in ("CharField", "TextField", "JSONField")
                 )
 
         if not required_on_save:
diff --git a/wagtail/admin/tests/pages/test_create_page.py b/wagtail/admin/tests/pages/test_create_page.py
index 3aea7541fd..0af5e5583f 100644
--- a/wagtail/admin/tests/pages/test_create_page.py
+++ b/wagtail/admin/tests/pages/test_create_page.py
@@ -32,6 +32,7 @@ from wagtail.test.testapp.models import (
     StandardIndex,
 )
 from wagtail.test.utils import WagtailTestUtils
+from wagtail.test.utils.form_data import nested_form_data, streamfield
 from wagtail.test.utils.timestamps import submittable_timestamp
 
 
@@ -755,6 +756,68 @@ class TestPageCreation(WagtailTestUtils, TestCase):
             ).exists()
         )
 
+    def test_create_streampage_post_with_blank_body(self):
+        post_data = nested_form_data(
+            {
+                "title": "Stream page",
+                "slug": "stream-page",
+                "body": streamfield([]),
+            }
+        )
+        response = self.client.post(
+            reverse(
+                "wagtailadmin_pages:add",
+                args=("tests", "streampage", self.root_page.id),
+            ),
+            post_data,
+        )
+        # Find the page and check it
+        page = Page.objects.get(
+            path__startswith=self.root_page.path, slug="stream-page"
+        ).specific
+
+        # Should be redirected to edit page
+        self.assertRedirects(
+            response, reverse("wagtailadmin_pages:edit", args=(page.id,))
+        )
+
+        self.assertEqual(len(page.body), 0)
+        self.assertFalse(page.live)
+
+    def test_cannot_publish_streampage_with_blank_body(self):
+        post_data = nested_form_data(
+            {
+                "title": "Stream page",
+                "slug": "stream-page",
+                "body": streamfield([]),
+                "action-publish": "Publish",
+            }
+        )
+        response = self.client.post(
+            reverse(
+                "wagtailadmin_pages:add",
+                args=("tests", "streampage", self.root_page.id),
+            ),
+            post_data,
+        )
+        self.assertEqual(response.status_code, 200)
+
+        # Check that a form error was raised. The actual message as rendered
+        # ("This field is required.") is passed to the StreamBlock as part of
+        # StreamBlockValidationError.non_block_errors, whereas assertFormError
+        # only considers the message attribute (which is a generic error).
+        self.assertFormError(
+            response.context["form"], "body", "Validation error in StreamBlock"
+        )
+        self.assertContains(response, "This field is required.")
+
+        # Page should not have been created
+        self.assertFalse(
+            Page.objects.filter(
+                path__startswith=self.root_page.path, slug="stream-page"
+            ).exists()
+        )
+
     def test_create_simplepage_scheduled(self):
         go_live_at = timezone.now() + datetime.timedelta(days=1)
         expire_at = timezone.now() + datetime.timedelta(days=2)
diff --git a/wagtail/blocks/base.py b/wagtail/blocks/base.py
index 53138f64c5..5c4ce2f2c3 100644
--- a/wagtail/blocks/base.py
+++ b/wagtail/blocks/base.py
@@ -756,6 +756,9 @@ class BlockField(forms.Field):
         super().__init__(**kwargs)
 
     def clean(self, value):
+        # Pass required flag to the top-level block, so that dynamically setting it on the
+        # field (e.g. by defer_required_fields) is respected by the block.
+        self.block.set_meta_options({"required": self.required})
         return self.block.clean(value)
 
     def has_changed(self, initial_value, data_value):