fix: properly format empty object with JSON normalizer

Objects that yield no value or have no property will now properly be formatted into `{}` instead of `[]`.
CuyZ · Jul 22, 2024 · ba22b52 · ba22b52
1 parent 69e0e3a
commit ba22b52
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Showing 5 changed files with 60 additions and 2 deletions.
diff --git a/src/Normalizer/ArrayNormalizer.php b/src/Normalizer/ArrayNormalizer.php
@@ -4,6 +4,7 @@
 
 namespace CuyZ\Valinor\Normalizer;
 
+use CuyZ\Valinor\Normalizer\Transformer\EmptyObject;
 use CuyZ\Valinor\Normalizer\Transformer\RecursiveTransformer;
 
 use function array_map;
@@ -38,6 +39,8 @@ private function normalizeIterator(mixed $value): mixed
             }
 
             $value = array_map($this->normalizeIterator(...), $value);
+        } elseif ($value instanceof EmptyObject) {
+            return [];
         }
 
         return $value;

diff --git a/src/Normalizer/Formatter/JsonFormatter.php b/src/Normalizer/Formatter/JsonFormatter.php
@@ -5,6 +5,7 @@
 namespace CuyZ\Valinor\Normalizer\Formatter;
 
 use CuyZ\Valinor\Normalizer\Formatter\Exception\CannotFormatInvalidTypeToJson;
+use CuyZ\Valinor\Normalizer\Transformer\EmptyObject;
 use Generator;
 
 use function array_is_list;
@@ -41,6 +42,8 @@ public function format(mixed $value): void
              *                             tools understand that JSON_THROW_ON_ERROR is always set.
              */
             $this->write(json_encode($value, $this->jsonEncodingOptions));
+        } elseif ($value instanceof EmptyObject) {
+            $this->write('{}');
         } elseif (is_iterable($value)) {
             // Note: when a generator is formatted, it is considered as a list
             // if its first key is 0. This is done early because the first JSON

diff --git a/src/Normalizer/Transformer/EmptyObject.php b/src/Normalizer/Transformer/EmptyObject.php
@@ -0,0 +1,13 @@
+<?php
+
+declare(strict_types=1);
+
+namespace CuyZ\Valinor\Normalizer\Transformer;
+
+use CuyZ\Valinor\Utility\IsSingleton;
+
+/** @internal */
+final class EmptyObject
+{
+    use IsSingleton;
+}
diff --git a/src/Normalizer/Transformer/RecursiveTransformer.php b/src/Normalizer/Transformer/RecursiveTransformer.php
@@ -24,6 +24,7 @@
 use function is_a;
 use function is_array;
 use function is_iterable;
+use function is_object;
 
 /**  @internal */
 final class RecursiveTransformer
@@ -105,11 +106,17 @@ private function defaultTransformer(mixed $value, WeakMap $references): mixed
                 );
             }
 
-            return (function () use ($value, $references) {
+            $result = (function () use ($value, $references) {
                 foreach ($value as $key => $item) {
                     yield $key => $this->doTransform($item, $references);
                 }
             })();
+
+            if (! $result->valid()) {
+                return EmptyObject::get();
+            }
+
+            return $result;
         }
 
         if (is_object($value) && ! $value instanceof Closure) {
@@ -126,9 +133,15 @@ private function defaultTransformer(mixed $value, WeakMap $references): mixed
             }
 
             if ($value::class === stdClass::class) {
+                $result = (array)$value;
+
+                if ($result === []) {
+                    return EmptyObject::get();
+                }
+
                 return array_map(
                     fn (mixed $value) => $this->doTransform($value, $references),
-                    (array)$value
+                    $result
                 );
             }
 

diff --git a/tests/Integration/Normalizer/NormalizerTest.php b/tests/Integration/Normalizer/NormalizerTest.php
@@ -695,6 +695,32 @@ public function __construct(
             'transformerAttributes' => [],
             'jsonEncodingOptions' => JSON_HEX_AMP,
         ];
+
+        yield 'stdClass with no property' => [
+            'input' => new stdClass(),
+            'expected array' => [],
+            'expected_json' => '{}',
+        ];
+
+        yield 'ArrayObject with no property' => [
+            'input' => new ArrayObject(),
+            'expected array' => [],
+            'expected_json' => '{}',
+        ];
+
+        yield 'iterable class with no property' => [
+            'input' => new class () implements IteratorAggregate {
+                public function getIterator(): Traversable
+                {
+                    // @phpstan-ignore-next-line / Empty array is here on purpose
+                    foreach ([] as $value) {
+                        yield $value;
+                    }
+                }
+            },
+            'expected array' => [],
+            'expected_json' => '{}',
+        ];
     }
 
     public function test_generator_of_scalar_yields_expected_array(): void