Issue #3273454: Field path is unknown when path is not installed

src/ContentExporter.php

@@ -161,7 +161,7 @@ class ContentExporter implements ContentExporterInterface {
             'created' => $entity->getCreatedTime(),
             'changed' => $entity->getChangedTime(),
             'author' => $owner ? $owner->getEmail() : NULL,
-            'url' => $entity->get('path')->alias ?? NULL,
+            'url' => $entity->hasField('path') ? $entity->get('path')->alias : NULL
           ];
         }
         break;

src/ContentImporter.php

@@ -363,17 +363,21 @@ class ContentImporter implements ContentImporterInterface {
 
     switch ($entity_type_id) {
       case 'node':
-        return [
+        $node = [
           'title' => $values['title'],
           'langcode' => $values['langcode'],
           'created' => $values['created'],
           'changed' => $values['changed'],
           'status' => $values['status'],
-          'path' => [
+        ];
+        // We check if node url alias is filled in.
+        if (isset($values['url'])) {
+          $node = [
             'alias' => $values['url'],
             'pathauto' => empty($values['url']),
-          ],
-        ];
+          ];
+        }
+        return $node;
 
       case 'user':
         return [