FIX Don't try to access private properties/methods

src/Core/CustomMethods.php

@@ -147,7 +147,13 @@ protected function registerExtraMethodCallback($name, $callback)
      */
     public function hasMethod($method)
     {
-        return method_exists($this, $method ?? '') || $this->getExtraMethodConfig($method);
+        return (method_exists($this, $method ?? '') && !$this->isPrivateMethod($method)) || $this->getExtraMethodConfig($method);
+    }
+
+    private function isPrivateMethod(string $method): bool
+    {
+        $reflectionMethod = new ReflectionMethod($this, $method);
+        return $reflectionMethod->isPrivate();
     }
 
     /**

src/View/ViewableData.php

@@ -7,7 +7,9 @@
 use InvalidArgumentException;
 use IteratorAggregate;
 use LogicException;
+use ReflectionMethod;
 use ReflectionObject;
+use ReflectionProperty;
 use SilverStripe\Core\ClassInfo;
 use SilverStripe\Core\Config\Config;
 use SilverStripe\Core\Config\Configurable;
@@ -111,7 +113,7 @@ public function __construct()
     public function __isset($property)
     {
         // getField() isn't a field-specific getter and shouldn't be treated as such
-        if (strtolower($property ?? '') !== 'field' && $this->hasMethod($method = "get$property")) {
+        if (strtolower($property ?? '') !== 'field' && $this->hasMethod("get$property")) {
             return true;
         }
         if ($this->hasField($property)) {
@@ -159,20 +161,13 @@ public function __set($property, $value)
         $this->objCacheClear();
         $method = "set$property";
 
-        if ($this->hasMethod($method) && !$this->isPrivate($this, $method)) {
+        if ($this->hasMethod($method)) {
             $this->$method($value);
         } else {
             $this->setField($property, $value);
         }
     }
 
-    private function isPrivate(object $class, string $method): bool
-    {
-        $class = new ReflectionObject($class);
-
-        return $class->getMethod($method)->isPrivate();
-    }
-
     /**
      * Set a failover object to attempt to get data from if it is not present on this object.
      *
@@ -207,7 +202,13 @@ public function getFailover()
      */
     public function hasField($field)
     {
-        return property_exists($this, $field) || isset($this->data[$field]);
+        return (property_exists($this, $field) && !$this->isPrivateProperty($field)) || isset($this->data[$field]);
+    }
+
+    private function isPrivateProperty(string $property): bool
+    {
+        $reflectionProperty = new ReflectionProperty($this, $property);
+        return $reflectionProperty->isPrivate();
     }
 
     /**

tests/php/View/ViewableDataTest.php

@@ -208,16 +208,35 @@ public function testSetFailover()
         $this->assertFalse($container->hasMethod('testMethod'), 'testMethod() incorrectly reported as existing');
     }
 
-    public function testIsPrivate()
+    public function testIsPrivateMethod()
     {
-        $reflectionMethod = new ReflectionMethod(ViewableData::class, 'isPrivate');
+        $reflectionMethod = new ReflectionMethod(ViewableData::class, 'isPrivateMethod');
         $reflectionMethod->setAccessible(true);
         $object = new ViewableDataTestObject();
-
-        $output = $reflectionMethod->invokeArgs($object, [$object, 'privateMethod']);
-        $this->assertTrue($output, 'Method is not private');
-
-        $output = $reflectionMethod->invokeArgs($object, [$object, 'publicMethod']);
-        $this->assertFalse($output, 'Method is private');
+
+        $output = $reflectionMethod->invokeArgs($object, ['privateMethod']);
+        $this->assertTrue($output, 'Method should be private');
+
+        $output = $reflectionMethod->invokeArgs($object, ['protectedMethod']);
+        $this->assertFalse($output, 'Method should not be private');
+
+        $output = $reflectionMethod->invokeArgs($object, ['publicMethod']);
+        $this->assertFalse($output, 'Method should not be private');
+    }
+
+    public function testIsPrivateProperty()
+    {
+        $reflectionMethod = new ReflectionMethod(ViewableData::class, 'isPrivateProperty');
+        $reflectionMethod->setAccessible(true);
+        $object = new ViewableDataTestObject();
+
+        $output = $reflectionMethod->invokeArgs($object, ['privateProperty']);
+        $this->assertTrue($output, 'Property should be private');
+
+        $output = $reflectionMethod->invokeArgs($object, ['protectedProperty']);
+        $this->assertFalse($output, 'Property should not be private');
+
+        $output = $reflectionMethod->invokeArgs($object, ['publicProperty']);
+        $this->assertFalse($output, 'Property should not be private');
     }
 }

tests/php/View/ViewableDataTestObject.php

@@ -7,11 +7,22 @@
 
 class ViewableDataTestObject extends DataObject implements TestOnly
 {
+    private string $privateProperty = 'private property';
+
+    protected string $protectedProperty = 'protected property';
+
+    public string $publicProperty = 'public property';
+
     private function privateMethod(): string
     {
         return 'Private function';
     }
 
+    protected function protectedMethod(): string
+    {
+        return 'Protected function';
+    }
+
     public function publicMethod(): string
     {
         return 'Public function';