Revert "Issue #1813832 by andypost, xjm, sun: Fixed Entity wrongly checks...

Revert "Issue #1813832 by andypost, xjm, sun: Fixed Entity wrongly checks existence of ID in isNew() method."

This reverts commit 453b2517.

This broke testbot. Reverting temporarily.

core/lib/Drupal/Core/Config/Entity/ConfigEntityBase.php

@@ -51,7 +51,7 @@ public function getOriginalID() {
    * since each configuration entity is unique.
    */
   final public function isNew() {
-    return $this->id() === NULL;
+    return !$this->id();
   }
 
   /**

core/lib/Drupal/Core/Entity/Entity.php

@@ -91,7 +91,7 @@ public function uuid() {
    * Implements EntityInterface::isNew().
    */
   public function isNew() {
-    return !empty($this->enforceIsNew) || $this->id() === NULL;
+    return !empty($this->enforceIsNew) || !$this->id();
   }
 
   /**

core/modules/config/lib/Drupal/config/Tests/ConfigEntityTest.php

@@ -85,19 +85,6 @@ function testCRUD() {
     $this->assertResponse(200);
     $this->assertNoText($label1);
     $this->assertText($label3);
-
-    // Create a configuration entity with '0' machine name.
-    $edit = array(
-      'id' => '0',
-      'label' => '0',
-    );
-    $this->drupalPost('admin/structure/config_test/add', $edit, 'Save');
-    $this->assertResponse(200);
-    $message_insert = format_string('%label configuration has been created.', array('%label' => $edit['id']));
-    $this->assertRaw($message_insert);
-
-    $this->drupalPost('admin/structure/config_test/manage/0/delete', array(), 'Delete');
-    $this->assertFalse(entity_load('config_test', '0'), 'Test entity deleted');
   }
 
 }