Actually check the database for getHasDescendants() / getTotalDescend…

…ants()

Fixes #4504

CHANGELOG-v3.md

@@ -18,6 +18,7 @@
 - Fixed an error that could occur if a template was accessing the deprecated `locale` property of an element query, but `siteId` wasn’t set to an integer. ([#4531](https://github.com/craftcms/cms/issues/4531))
 - Fixed a bug where users without the “Publish live changes” permission for a section weren’t able to create new entries. ([#4528](https://github.com/craftcms/cms/issues/4529))
 - Fixed a PHP error that could occur when uploading files to Assets fields on the front-end. ([#4382](https://github.com/craftcms/cms/issues/4382))
+- Fixed a bug where elements listed in a Structure view could show descendant toggles even if they had no descendants. ([#4504](https://github.com/craftcms/cms/issues/4504))
 
 ## 3.2.0 - 2019-07-09
 

src/base/Element.php

@@ -1632,19 +1632,23 @@ public function getNextSibling()
      */
     public function getHasDescendants(): bool
     {
-        return ($this->lft !== null && $this->rgt !== null && $this->rgt > $this->lft + 1);
+        $descendants = $this->getDescendants();
+        if (is_array($descendants)) {
+            return !empty($descendants);
+        }
+        return $descendants->exists();
     }
 
     /**
      * @inheritdoc
      */
     public function getTotalDescendants(): int
     {
-        if ($this->getHasDescendants()) {
-            return ($this->rgt - $this->lft - 1) / 2;
+        $descendants = $this->getDescendants();
+        if (is_array($descendants)) {
+            return count($descendants);
         }
-
-        return 0;
+        return $descendants->count();
     }
 
     /**