Fix extending context with partial hash arguments

Also fixed stringification of arrays returned by block helpers.

Author: theodorejb

src/HelperOptions.php

@@ -20,6 +20,7 @@ final class HelperOptions
      * @param array<mixed> $data
      * @param array<mixed> $hash
      * @param array<mixed> $outerBlockParams outer block param stack, passed as trailing elements of the stack
+     * @internal
      */
     public function __construct(
         public mixed &$scope,

src/Runtime.php

@@ -375,18 +375,10 @@ public static function section(RuntimeContext $cx, mixed $value, mixed $in, ?Clo
     /**
      * Merge context objects, equivalent to Utils.extend() in Handlebars.js.
      */
-    public static function extend(mixed $a, mixed $b): mixed
+    private static function extend(mixed $a, mixed $b): mixed
     {
         if (is_array($b)) {
-            if ($a === null || is_int($a)) {
-                return $b;
-            } elseif (is_array($a)) {
-                return array_replace($a, $b);
-            } elseif (is_object($a)) {
-                foreach ($b as $i => $v) {
-                    $a->$i = $v;
-                }
-            }
+            return is_array($a) ? array_replace($a, $b) : $b;
         }
         return $a;
     }
@@ -560,7 +552,7 @@ private static function resolveBlockResult(RuntimeContext $cx, mixed $result, mi
 
         // Arrays stringify like JS Array.prototype.toString(), regardless of fn block.
         if (is_array($result)) {
-            return implode(',', $result);
+            return self::raw($result);
         }
 
         if ($cb === null) {

tests/RegressionTest.php

@@ -766,8 +766,13 @@ public static function helperProvider(): array
             ],
             'block helper returning truthy non-string: stringified like JS' => [
                 'template' => '{{#helper}}block{{/helper}}',
-                'helpers' => ['helper' => fn() => ['truthy', 'array']],
-                'expected' => 'truthy,array',
+                'helpers' => ['helper' => fn() => ['a', ['ba', 'bb'], 'c']],
+                'expected' => 'a,ba,bb,c',
+            ],
+            'block helper returning non-list array: stringified like JS' => [
+                'template' => '{{#helper}}block{{/helper}}',
+                'helpers' => ['helper' => fn() => ['a' => 'foo', 'b' => 'bar']],
+                'expected' => '[object Object]',
             ],
             'inverted known block helper returning truthy non-string: stringified like JS' => [
                 'template' => '{{^helper}}block{{/helper}}',
@@ -1142,6 +1147,13 @@ public static function partialProvider(): array
                 'data' => ['condition' => false],
                 'expected' => ' Failover',
             ],
+
+            'partial hash arguments replace scalar context' => [
+                'template' => '{{#with str}}{{> myPartial key="val"}}{{/with}}',
+                'partials' => ['myPartial' => '{{key}}'],
+                'data' => ['str' => 'hello'],
+                'expected' => 'val',
+            ],
         ];
     }