Fix null values for composed structs

Author: markusjwetzel

src/Casts/ComposedStructCast.php

@@ -69,18 +69,18 @@ public function get($model, $key, $value, $attributes)
      */
     public function set($model, $key, $value, $attributes)
     {
+        $class = $this->class;
+
         if (is_null($value)) {
-            return null;
-        }
+            $value = array_fill_keys($class::getPropertyNames(), null);
+        } else {
+            if (! $value instanceof Struct) {
+                throw new InvalidArgumentException('The given value is not a struct instance, "'.get_class($value).'" given.');
+            }
 
-        if (! $value instanceof Struct) {
-            throw new InvalidArgumentException('The given value is not a struct instance, "'.get_class($value).'" given.');
+            $value = $class::serializeDatabase($value);
         }
 
-        $class = $this->class;
-
-        $value = $class::serializeDatabase($value);
-
         return $this->composeProperties($key, $value);
     }
 

src/Struct.php

@@ -30,7 +30,7 @@ abstract class Struct implements Arrayable, JsonSerializable, Castable
      */
     public function __construct(array $properties = [])
     {
-        $reflections = $this->getReflectionProperties();
+        $reflections = static::getReflectionProperties();
 
         foreach ($reflections as $reflection) {
             $name = $reflection->getName();
@@ -89,20 +89,38 @@ protected function buildInstance($class, $value)
         return new $class($value);
     }
 
+    /**
+     * Get the property names.
+     *
+     * @return array
+     */
+    public static function getPropertyNames()
+    {
+        $reflections = static::getReflectionProperties();
+
+        $result = [];
+
+        foreach($reflections as $reflection) {
+            $name = $reflection->getName();
+            $result[] = $name;
+        }
+
+        return $result;
+    }
+
     /**
      * Get the properties.
      *
      * @return array
      */
     public function getProperties()
     {
-        $reflections = $this->getReflectionProperties();
+        $reflections = static::getReflectionProperties();
 
         $result = [];
 
         foreach($reflections as $reflection) {
             $name = $reflection->getName();
-
             $result[$name] = $this->{$name};
         }
 
@@ -126,7 +144,7 @@ public function toArray()
      *
      * @return \ReflectionProperty[]
      */
-    protected function getReflectionProperties()
+    protected static function getReflectionProperties()
     {
         if (isset(static::$cache[static::class])) {
             return static::$cache[static::class];