fix calling __toString() on null values (acseo#109)

Author: npotier

src/Transformer/DoctrineToTypesenseTransformer.php

@@ -89,6 +89,8 @@ public function castValue(string $entityClass, string $propertyName, $value)
         $originalType                = $collectionFieldsDefinitions[$key]['type'];
         $castedType                  = $this->castType($originalType);
 
+        $isOptional = $collectionFieldsDefinitions[$key]['optional'] ?? false;
+
         switch ($originalType.$castedType) {
             case self::TYPE_DATETIME.self::TYPE_INT_64:
                 if ($value instanceof \DateTimeInterface) {
@@ -97,10 +99,16 @@ public function castValue(string $entityClass, string $propertyName, $value)
 
                 return null;
             case self::TYPE_OBJECT.self::TYPE_STRING:
+                if ($isOptional == true && $value == null) {
+                    return null;
+                }
                 return $value->__toString();
             case self::TYPE_COLLECTION.self::TYPE_ARRAY_STRING:
                 return array_values(
-                    $value->map(function ($v) {
+                    $value->map(function ($v) use($isOptional) {
+                        if ($isOptional == true && $v == null) {
+                            return null;
+                        }
                         return $v->__toString();
                     })->toArray()
                 );

tests/Unit/Transformer/DoctrineToTypesenseTransformerTest.php

@@ -35,13 +35,13 @@ public function bookData()
     {
         return [
             [
-                new Book(1, 'test', new Author('Nicolas Potier', 'France'), new \Datetime('01/01/1984 00:00:00')),
+                new Book(1, 'test', null, new \Datetime('01/01/1984 00:00:00')),
                 [
                     "id" => "1",
                     "sortable_id" => 1,
                     "title" => "test",
-                    "author" => "Nicolas Potier",
-                    "author_country" => "France",
+                    "author" => null,
+                    "author_country" => null,
                     "published_at" => 441763200,
                     "active" => false,
                     "cover_image_url" => "http://fake.image/1"
@@ -238,6 +238,7 @@ private function getCollectionDefinitions($entityClass)
                         'name'             => 'author',
                         'type'             => 'object',
                         'entity_attribute' => 'author',
+                        'optional'         => true
                     ],
                     'michel' => [
                         'name'             => 'author_country',