ArraySchema to support 'empty' pseudo type

Civi/Inlay/ArraySchema.php

@@ -82,7 +82,7 @@ class ArraySchema {
       '//' => [ 'MUST', 'array',
         'schema' => [
           0 => ['MUST', 'string', 'oneOfStrictly' => ['MUST', 'MAY']],
-          1 => ['MUST', 'string|NULL', 'regex' => '/^(boolean|integer|integerString|numeric|double|string|array|NULL)([|](boolean|integer|integerString|numeric|double|string|array|NULL))*$/'],
+          1 => ['MUST', 'string|NULL', 'regex' => '/^(boolean|integer|double|string|array|NULL|integerString|numeric|empty)([|](boolean|integer|double|string|array|NULL|integerString|numeric|empty))*$/'],
           'schema' => ['MAY', 'array', 'recurse' => []],
           'regex' => ['MAY', 'string'],
           'recurse' => ['MAY', 'array', 'schema' => [
@@ -216,6 +216,10 @@ class ArraySchema {
           $typeOK = TRUE;
           break;
         }
+        if ($type === 'empty' && empty($value)) {
+          $typeOK = TRUE;
+          break;
+        }
       }
       if (!$typeOK) {
         return [["Expected $expectedTypes but got $actualType", $ancestry, $value]];

Civi/Inlay/Type.php

@@ -194,6 +194,7 @@ abstract class Type {
     // Note: because of the way CRM.url works, you MUST put a ? before the #
     return 'civicrm/a?#/inlays/' . static::getTypeMachineName() . '/{id}';
   }
+
   /**
    * Get the URL template for editing config sets belonging to this inlay type.
    *
@@ -205,6 +206,7 @@ abstract class Type {
     // Note: because of the way CRM.url works, you MUST put a ? before the #
     return "civicrm/a?#/inlayConfig/$configSetName/{id}";
   }
+
   /**
    * Load the config from the given Array.
    *