Issue #3210926 by kriboogh: Call to a member function getAlias on null in PathItem->postSave()

Closes #3210926

core/modules/path/src/Plugin/Field/FieldType/PathItem.php

@@ -85,8 +85,16 @@ public function postSave($update) {
       }
       elseif ($this->pid) {
         $path_alias = $path_alias_storage->load($this->pid);
-
-        if ($this->alias != $path_alias->getAlias()) {
+        if (!$path_alias) {
+          $path_alias = $path_alias_storage->create([
+            'path' => '/' . $entity->toUrl()->getInternalPath(),
+            'alias' => $this->alias,
+            'langcode' => $alias_langcode,
+          ]);
+          $path_alias->save();
+          $this->pid = $path_alias->id();
+        }
+        elseif ($this->alias != $path_alias->getAlias()) {
           $path_alias->setAlias($this->alias);
           $path_alias->save();
         }