Issue #3491369 by just_like_good_vibes, pdureau, grimreaper, walli: Props with...

Issue #3491369 by just_like_good_vibes, pdureau, grimreaper, walli: Props with enum should handle empty string or NULL value (2)

src/EnumTrait.php

@@ -101,15 +101,49 @@ trait EnumTrait {
   protected static function enumDefaultValue(?array $definition = NULL): mixed {
     // First get the enum array.
     $enum = (!is_array($definition)) ? [] : ($definition['enum'] ?? []);
-    if (!is_array($enum)) {
-      $enum = [];
+    if (!is_array($enum) || empty($enum)) {
+      return NULL;
     }
     // Fall back to default value (if defined)
-    if (is_array($definition) && isset($definition['default'])) {
+    if (isset($definition['default'])) {
       return $definition['default'];
     }
-    // If a type is defined, return the first enum value.
-    return (is_array($definition) && isset($definition['type']) && count($enum) > 0) ? $enum[0] : NULL;
+    // Return the first value, when:
+    // - a value is required
+    // - or the type is defined and not string compatible.
+    if (static::isEnumRequired($definition) ||
+      (isset($definition['type']) && !static::isEnumTypeStringCompatible($definition))) {
+      return (count($enum) > 0) ? $enum[0] : NULL;
+    }
+    return "";
+  }
+
+  /**
+   * Check if the enum type accepts string values.
+   *
+   * @param array $definition
+   *   The definition.
+   *
+   * @return bool
+   *   Whether the enum type accepts string values.
+   */
+  protected static function isEnumTypeStringCompatible(array $definition): bool {
+    $type = $definition['type'] ?? [];
+    return ($type === "string") || (is_array($type) && in_array('string', $definition['type'], TRUE));
+  }
+
+  /**
+   * Check if the enum has a required value.
+   *
+   * @param array $definition
+   *   The definition.
+   *
+   * @return bool
+   *   Whether the enum has a required value.
+   */
+  protected static function isEnumRequired(array $definition): bool {
+    $required_prop = $definition['required'] ?? FALSE;
+    return $required_prop === TRUE;
   }
 
   /**