#3498269: PHP warnings thrown for optional image or date-time SDC props without examples

src/Plugin/ExperienceBuilder/ComponentSource/SingleDirectoryComponent.php

@@ -379,9 +379,15 @@ final class SingleDirectoryComponent extends ComponentSourceBase implements Comp
       // @see \Drupal\experience_builder\Entity\Component::getDefaultsForComponentPlugin
       $is_datetime = isset($prop_info['format']) && $prop_info['format'] === 'date-time';
       // @todo DateTimeItem stores information in a format that clashes with JSON schema's, and it has no automatic conversion. Figure out a better solution for both this and \Drupal\experience_builder\PropExpressions\StructuredData\Evaluator::evaluate().
-      $default_value = ($is_image || $is_datetime)
-        ? $prop_info['examples'][0]
-        : $component->getDefaultStaticPropSource($component_prop->propName)->evaluate(NULL);
+      $default_value = NULL;
+      if (($is_image || $is_datetime)) {
+        if (isset($prop_info['examples']) && is_array($prop_info['examples']) && !empty($prop_info['examples'])) {
+          $default_value = $prop_info['examples'][0];
+        }
+      }
+      else {
+        $default_value = $component->getDefaultStaticPropSource($component_prop->propName)->evaluate(NULL);
+      }
       if ($default_value !== NULL) {
         $keyed_choices[$component_prop->propName]['default_values'] = $default_value;
         $default_props_for_default_markup[$component_prop->propName] = $default_value;