Make StreamField chooser blocks values nullable (#396)

CHANGELOG.md

@@ -1,5 +1,9 @@
 ## Unreleased
 
+### Changed
+
+-   Make value fields nullable on `PageChooserBlock`, `SnippetChooserBlock`, `DocumentChooserBlock` and `ImageChooserBlock` ([#396](https://github.com/torchbox/wagtail-grapple/pull/396))
+
 ## [0.25.1] - 2024-04-21
 
 ### Changed

grapple/types/streamfield.py

@@ -436,7 +436,7 @@ def register_streamfield_blocks():
     from .snippets import SnippetTypes
 
     class PageChooserBlock(graphene.ObjectType):
-        page = graphene.Field(get_page_interface(), required=True)
+        page = graphene.Field(get_page_interface(), required=False)
 
         class Meta:
             interfaces = (StreamFieldInterface,)
@@ -445,7 +445,7 @@ def resolve_page(self, info, **kwargs):
             return self.value.specific
 
     class DocumentChooserBlock(graphene.ObjectType):
-        document = graphene.Field(get_document_type(), required=True)
+        document = graphene.Field(get_document_type(), required=False)
 
         class Meta:
             interfaces = (StreamFieldInterface,)
@@ -454,7 +454,7 @@ def resolve_document(self, info, **kwargs):
             return self.value
 
     class ImageChooserBlock(graphene.ObjectType):
-        image = graphene.Field(get_image_type(), required=True)
+        image = graphene.Field(get_image_type(), required=False)
 
         class Meta:
             interfaces = (StreamFieldInterface,)
@@ -474,7 +474,7 @@ def resolve_image(self, info, **kwargs):
     if SnippetObjectType is not None:
 
         class SnippetChooserBlock(graphene.ObjectType):
-            snippet = graphene.Field(SnippetObjectType, required=True)
+            snippet = graphene.Field(SnippetObjectType, required=False)
 
             class Meta:
                 interfaces = (StreamFieldInterface,)

tests/test_interfaces.py

@@ -80,7 +80,7 @@ def test_schema_for_page_with_graphql_interface(self):
             [{"name": "CustomInterface"}, {"name": "PageInterface"}],
         )
 
-    def test_schem_for_snippet_with_graphql_interface(self):
+    def test_schema_for_snippet_with_graphql_interface(self):
         results = self.introspect_schema_by_type("Advert")
         self.assertListEqual(
             sorted(results["data"]["__type"]["interfaces"], key=lambda x: x["name"]),

tests/test_models_types.py

@@ -1,7 +1,12 @@
 import graphene
 
 from django.test import TestCase
+from wagtail.blocks.field_block import PageChooserBlock
+from wagtail.documents.blocks import DocumentChooserBlock
+from wagtail.images.blocks import ImageChooserBlock
+from wagtail.snippets.blocks import SnippetChooserBlock
 
+from grapple import registry
 from grapple.actions import get_field_type
 from grapple.exceptions import IllegalDeprecation
 from grapple.models import (
@@ -183,3 +188,58 @@ def test_collection_field_required_deprecated(self):
                 required=True,
                 deprecation_reason=self.deprecation_reason,
             )()
+
+
+class ChooserBlocksTest(TestCase):
+    """
+    Test that "Chooser" blocks take null values to ensure correct handling
+    of deleted objects referenced in these blocks.
+    """
+
+    def test_snippet_chooser_block_value_field_not_required(self):
+        """
+        Test that the SnippetChooserBlock snippet field is nullable in the
+        GraphQL schema.
+        """
+        block = registry.registry.streamfield_blocks[SnippetChooserBlock]
+        field = block.snippet
+
+        # Check that field is not required by asserting type isn't `NonNull`
+        self.assertIsInstance(field, graphene.types.field.Field)
+        self.assertNotIsInstance(field.type, graphene.NonNull)
+
+    def test_document_chooser_block_value_field_not_required(self):
+        """
+        Test that the DocumentChooserBlock document field is nullable in the
+        GraphQL schema.
+        """
+        block = registry.registry.streamfield_blocks[DocumentChooserBlock]
+        field = block.document
+
+        # Check that field is not required by asserting type isn't `NonNull`
+        self.assertIsInstance(field, graphene.types.field.Field)
+        self.assertNotIsInstance(field.type, graphene.NonNull)
+
+    def test_image_chooser_block_value_field_not_required(self):
+        """
+        Test that the ImageChooserBlock image field is nullable in the GraphQL
+        schema.
+        """
+        block = registry.registry.streamfield_blocks[ImageChooserBlock]
+        field = block.image
+
+        # Check that field is not required by asserting type isn't `NonNull`
+        self.assertIsInstance(field, graphene.types.field.Field)
+        self.assertNotIsInstance(field.type, graphene.NonNull)
+
+    def test_page_chooser_block_value_field_not_required(self):
+        """
+        Test that the PageChooserBlock page field is nullable in the GraphQL
+        schema.
+        """
+        block = registry.registry.streamfield_blocks[PageChooserBlock]
+        field = block.page
+
+        # Check that field is not required by asserting type isn't `NonNull`
+        self.assertIsInstance(field, graphene.types.field.Field)
+        self.assertNotIsInstance(field.type, graphene.NonNull)