Schema UI handler - walk through properties recursive

[stefan-korn]

We use a distribution schema with properties (under the data key) that have properties themself. While this is working generally, schema UI is not applied to these subproperties.

I am thinking about walking through these properties recursive within the SchemaUiHandler. How about this?

diff --git a/modules/json_form_widget/src/SchemaUiHandler.php b/modules/json_form_widget/src/SchemaUiHandler.php
index 8d47b9a5e..f25b808bf 100644
--- a/modules/json_form_widget/src/SchemaUiHandler.php
+++ b/modules/json_form_widget/src/SchemaUiHandler.php
@@ -230,6 +230,9 @@ class SchemaUiHandler implements ContainerInjectionInterface {
     foreach ((array) $spec as $field => $sub_spec) {
       if (isset($element[$property][$field])) {
         $element[$property][$field] = $this->applyOnBaseField($sub_spec, $element[$property][$field]);
+        if (isset($sub_spec->properties)) {
+          $element[$property][$field] = $this->applyOnObjectFields($field, $sub_spec->properties, $element[$property][$field]);
+        }
       }
     }
     return $element;

@dafeder : Would like to discuss, get your input, before maybe opening an issue and PR.

The intention on our end was to hide some of the properties with schema ui. This works with the patch above. But I am not exactly sure if other schema ui changes would also work, need to get into details here maybe.