Optimize inline helpers which don't use options

This makes it possible to use native PHP functions as inline helpers with first-class callable syntax, since the function will no longer be passed an extra options argument.

Author: theodorejb

src/Runtime.php

@@ -467,15 +467,29 @@ public static function dynhbch(RuntimeContext $cx, string $name, array $position
      */
     public static function hbch(RuntimeContext $cx, \Closure $helper, string $name, array $positional, array $hash, mixed &$_this): mixed
     {
-        $options = new HelperOptions(
-            scope: $_this,
-            data: $cx->frame,
-            name: $name,
-            hash: $hash,
-        );
-        $args = $positional;
-        $args[] = $options;
-        return $helper(...$args);
+        /** @var \WeakMap<\Closure, int>|null $paramCounts */
+        static $paramCounts = null;
+        $paramCounts ??= new \WeakMap();
+
+        $numParams = $paramCounts[$helper] ?? null;
+        if ($numParams === null) {
+            // Cache the number of parameters for the closure so HelperOptions doesn't have to be instantiated
+            // when it isn't used. This can boost runtime performance by 20% for complex templates.
+            $rf = new \ReflectionFunction($helper);
+            $params = $rf->getParameters();
+            $numParams = $params && end($params)->isVariadic() ? 0 : $rf->getNumberOfParameters();
+            $paramCounts[$helper] = $numParams;
+        }
+        if ($numParams === 0 || $numParams > count($positional)) {
+            $positional[] = new HelperOptions(
+                scope: $_this,
+                data: $cx->frame,
+                name: $name,
+                hash: $hash,
+            );
+        }
+
+        return $helper(...$positional);
     }
 
     /**

tests/RegressionTest.php

@@ -202,7 +202,7 @@ public static function helperProvider(): array
                 'desc' => 'LNC#49 - custom helper alias',
                 'template' => '{{date_format date "M j, Y"}}',
                 'helpers' => [
-                    'date_format' => fn($date, $format) => date_format($date, $format),
+                    'date_format' => date_format(...),
                 ],
                 'data' => ['date' => new \DateTime('2014-06-06')],
                 'expected' => 'Jun 6, 2014',