Add support for stdClass empty and annotated object handling in Stringifier

Author: antonmedv

src/Stringifier.php

@@ -26,6 +26,9 @@ public static function stringify(mixed $value): string
             }
             return $leading . self::stringifyObject($value, 0, $annotated);
         }
+        if ($value instanceof \stdClass) {
+            return $leading . self::stringifyObject((array) $value, 0, $annotated);
+        }
         if ($annotated !== null) {
             foreach ($annotated->danglingComments as $c) {
                 $dangling .= "\n" . '#' . $c;
@@ -66,6 +69,9 @@ private static function doStringify(mixed $value, int $level): string
             }
             return self::stringifyObject($value, $level, $annotated);
         }
+        if ($value instanceof \stdClass) {
+            return self::stringifyObject((array) $value, $level, $annotated);
+        }
         throw new \InvalidArgumentException('Unsupported value type: ' . get_debug_type($value));
     }
 
@@ -100,7 +106,7 @@ private static function stringifyArray(array $arr, int $level, ?Annotated $annot
                 }
             }
             $out .= $childIndent . self::doStringify($arr[$i], $level + 1);
-            if ($elAnnotated !== null && $elAnnotated->trailingComment !== null && !is_array($innerValue)) {
+            if ($elAnnotated !== null && $elAnnotated->trailingComment !== null && !is_array($innerValue) && !$innerValue instanceof \stdClass) {
                 $out .= ' #' . $elAnnotated->trailingComment;
             }
         }
@@ -123,6 +129,9 @@ private static function stringifyObject(array $obj, int $level, ?Annotated $anno
     {
         $keys = array_keys($obj);
         $hasDangling = $annotated !== null && count($annotated->danglingComments) > 0;
+        if (count($keys) === 0 && !$hasDangling) {
+            return '{}';
+        }
         $childIndent = self::getIndent($level + 1);
         $parentIndent = self::getIndent($level);
         $out = "{\n";
@@ -146,7 +155,7 @@ private static function stringifyObject(array $obj, int $level, ?Annotated $anno
                 }
             }
             $out .= $childIndent . self::stringifyKey($key) . ': ' . self::doStringify($obj[$key], $level + 1);
-            if ($elAnnotated !== null && $elAnnotated->trailingComment !== null && !is_array($innerValue)) {
+            if ($elAnnotated !== null && $elAnnotated->trailingComment !== null && !is_array($innerValue) && !$innerValue instanceof \stdClass) {
                 $out .= ' #' . $elAnnotated->trailingComment;
             }
         }

tests/StringifierTest.php

@@ -319,6 +319,53 @@ public function testCombinedAnnotations(): void
         $this->assertSame($expected, Maml::stringify($data));
     }
 
+    // --- stdClass (empty object) tests ---
+
+    public function testEmptyStdClass(): void
+    {
+        $this->assertSame('{}', Maml::stringify(new \stdClass()));
+    }
+
+    public function testEmptyObjectCast(): void
+    {
+        $this->assertSame('{}', Maml::stringify((object) []));
+    }
+
+    public function testStdClassWithProperties(): void
+    {
+        $data = (object) ['name' => 'test', 'count' => 3];
+        $expected = "{\n  name: \"test\"\n  count: 3\n}";
+        $this->assertSame($expected, Maml::stringify($data));
+    }
+
+    public function testNestedEmptyObject(): void
+    {
+        $data = ['config' => new \stdClass()];
+        $expected = "{\n  config: {}\n}";
+        $this->assertSame($expected, Maml::stringify($data));
+    }
+
+    public function testEmptyObjectInArray(): void
+    {
+        $data = [new \stdClass(), new \stdClass()];
+        $expected = "[\n  {}\n  {}\n]";
+        $this->assertSame($expected, Maml::stringify($data));
+    }
+
+    public function testAnnotatedEmptyObjectWithDanglingComment(): void
+    {
+        $data = ['plugins' => Annotated::with(new \stdClass())->danglingComment(' Add here')];
+        $expected = "{\n  plugins: {\n    # Add here\n  }\n}";
+        $this->assertSame($expected, Maml::stringify($data));
+    }
+
+    public function testTrailingCommentOnStdClassIsIgnored(): void
+    {
+        $data = ['x' => Annotated::with(new \stdClass())->trailingComment(' ignored')];
+        $expected = "{\n  x: {}\n}";
+        $this->assertSame($expected, Maml::stringify($data));
+    }
+
     public function testDocumentWithLeadingAndDanglingComments(): void
     {
         $data = Annotated::with([