Add missing condition for StreamBlockComparison

CHANGELOG.txt

@@ -17,6 +17,7 @@ Changelog
  * Fix: `WAGTAILFRONTENDCACHE_LANGUAGES` was being interpreted incorrectly. It now accepts a list of strings, as documented (Karl Hobley)
  * Fix: Update oEmbed endpoints to use https where available (Matt Westcott)
  * Fix: Revise `edit_handler` bind order in ModelAdmin views and fix duplicate form instance creation (Jérôme Lebleu)
+ * Fix: Properly distinguish child blocks when comparing revisions with nested StreamBlocks (Martin Mena)
 
 
 2.10.2 (xx.xx.xxxx) - IN DEVELOPMENT

docs/releases/2.11.rst

@@ -31,6 +31,7 @@ Bug fixes
  * ``WAGTAILFRONTENDCACHE_LANGUAGES`` was being interpreted incorrectly. It now accepts a list of strings, as documented (Karl Hobley)
  * Update oEmbed endpoints to use https where available (Matt Westcott)
  * Revise ``edit_handler`` bind order in ModelAdmin views and fix duplicate form instance creation (Jérôme Lebleu)
+ * Properly distinguish child blocks when comparing revisions with nested StreamBlocks (Martin Mena)
 
 
 Upgrade considerations

wagtail/admin/compare.py

@@ -74,6 +74,8 @@ def get_comparison_class_for_block(block):
         return RichTextBlockComparison
     elif isinstance(block, blocks.StructBlock):
         return StructBlockComparison
+    elif isinstance(block, blocks.StreamBlock):
+        return StreamBlockComparison
     else:
         # As all stream field blocks have a HTML representation, fall back to diffing that.
         return RichTextBlockComparison

wagtail/admin/tests/test_compare.py

@@ -419,6 +419,28 @@ class TestStreamFieldComparison(TestCase):
         self.assertIsInstance(comparison.htmldiff(), SafeString)
         self.assertTrue(comparison.has_changed())
 
+    def test_compare_nested_streamblock_uses_comparison_class(self):
+        field = StreamPage._meta.get_field('body')
+        stream_block = field.stream_block.child_blocks['books']
+        comparison = self.comparison_class(
+            field,
+            StreamPage(body=StreamValue(field.stream_block, [
+                ('books', StreamValue(stream_block, [('title', 'The Old Man and the Sea', '10')]), '1'),
+            ])),
+            StreamPage(body=StreamValue(field.stream_block, [
+                ('books', StreamValue(stream_block, [('author', 'Oscar Wilde', '11')]), '1'),
+            ])),
+        )
+        expected = """
+            <div class="comparison__child-object">
+                <div class="comparison__child-object addition">Oscar Wilde</div>\n
+                <div class="comparison__child-object deletion">The Old Man and the Sea</div>
+            </div>
+        """
+        self.assertHTMLEqual(comparison.htmldiff(), expected)
+        self.assertIsInstance(comparison.htmldiff(), SafeString)
+        self.assertTrue(comparison.has_changed())
+
     def test_compare_imagechooserblock(self):
         image_model = get_image_model()
         test_image_1 = image_model.objects.create(

wagtail/tests/testapp/migrations/0056_streampage_nested_streamblock.py

@@ -0,0 +1,21 @@
+# Generated by Django 3.0.9 on 2020-08-12 20:27
+
+from django.db import migrations
+import wagtail.core.blocks
+import wagtail.core.fields
+import wagtail.tests.testapp.models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('tests', '0055_eventpage_childobject_i18n'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='streampage',
+            name='body',
+            field=wagtail.core.fields.StreamField([('text', wagtail.core.blocks.CharBlock()), ('rich_text', wagtail.core.blocks.RichTextBlock()), ('image', wagtail.tests.testapp.models.ExtendedImageChooserBlock()), ('product', wagtail.core.blocks.StructBlock([('name', wagtail.core.blocks.CharBlock()), ('price', wagtail.core.blocks.CharBlock())])), ('raw_html', wagtail.core.blocks.RawHTMLBlock()), ('books', wagtail.core.blocks.StreamBlock([('title', wagtail.core.blocks.CharBlock()), ('author', wagtail.core.blocks.CharBlock())]))]),
+        ),
+    ]

wagtail/tests/testapp/models.py

@@ -31,7 +31,7 @@ from wagtail.contrib.forms.views import SubmissionsListView
 from wagtail.contrib.settings.models import BaseSetting, register_setting
 from wagtail.contrib.sitemaps import Sitemap
 from wagtail.contrib.table_block.blocks import TableBlock
-from wagtail.core.blocks import CharBlock, RawHTMLBlock, RichTextBlock, StructBlock
+from wagtail.core.blocks import CharBlock, RawHTMLBlock, RichTextBlock, StreamBlock, StructBlock
 from wagtail.core.fields import RichTextField, StreamField
 from wagtail.core.models import Orderable, Page, PageManager, PageQuerySet, Task, TranslatableMixin
 from wagtail.documents.edit_handlers import DocumentChooserPanel
@@ -1024,6 +1024,10 @@ class StreamPage(Page):
             ('price', CharBlock()),
         ])),
         ('raw_html', RawHTMLBlock()),
+        ('books', StreamBlock([
+            ('title', CharBlock()),
+            ('author', CharBlock()),
+        ])),
     ])
 
     api_fields = ('body',)