Fixed sorting by groups in Flex Users

CHANGELOG.md

@@ -20,6 +20,7 @@
     * Fixed media crashing on a bad image
     * Fixed bug in collections where filter `type: false` did not work
     * Fixed `print_r()` in twig
+    * Fixed sorting by groups in `Flex Users`
 
 # v1.7.0-rc.17
 ## 10/07/2020
@@ -500,7 +501,6 @@
     * Fixed hardcoded system folder in blueprints, config and language streams
     * Added `.htaccess` rule to block attempts to use Twig in the request URL
 
-
 # v1.6.28
 ## 10/07/2020
 

system/src/Grav/Framework/Object/Collection/ObjectExpressionVisitor.php

@@ -11,6 +11,7 @@ namespace Grav\Framework\Object\Collection;
 
 use Doctrine\Common\Collections\Expr\ClosureExpressionVisitor;
 use Doctrine\Common\Collections\Expr\Comparison;
+use function is_callable;
 
 class ObjectExpressionVisitor extends ClosureExpressionVisitor
 {
@@ -27,7 +28,7 @@ class ObjectExpressionVisitor extends ClosureExpressionVisitor
 
         $pos = strpos($field, '(');
         if (false !== $pos) {
-            list ($op, $field) = explode('(', $field, 2);
+            [$op, $field] = explode('(', $field, 2);
             $field = rtrim($field, ')');
         }
 
@@ -39,7 +40,7 @@ class ObjectExpressionVisitor extends ClosureExpressionVisitor
             foreach ($accessors as $accessor) {
                 $accessor .= $field;
 
-                if (!method_exists($object, $accessor)) {
+                if (!is_callable([$object, $accessor])) {
                     continue;
                 }