Fix edge cases when passing null

Author: thekid

src/main/php/lang/reflection/Routine.class.php

@@ -99,10 +99,10 @@ public static function pass($reflect, $args) {
       if ($param->isVariadic()) {
         while ($args) $pass[]= array_shift($args);
         break;
-      } else if (isset($args[$param->name])) {
+      } else if (array_key_exists($param->name, $args)) {
         $pass[]= $args[$param->name];
         unset($args[$param->name]);
-      } else if (isset($args[$i])) {
+      } else if (array_key_exists($i, $args)) {
         $pass[]= $args[$i];
         unset($args[$i]);
       } else if ($param->isOptional()) {

src/test/php/lang/reflection/unittest/ArgumentPassingTest.class.php

@@ -13,6 +13,12 @@ public function pass_ordered() {
     Assert::equals([1, 2], Routine::pass($f, [1, 2]));
   }
 
+  #[Test]
+  public function pass_ordered_null() {
+    $f= new ReflectionFunction(fn($a, $b) => null);
+    Assert::equals([null, 2], Routine::pass($f, [null, 2]));
+  }
+
   #[Test, Expect(class: Error::class, message: 'Missing parameter $a')]
   public function missing() {
     $f= new ReflectionFunction(fn($a, $b) => null);
@@ -31,6 +37,12 @@ public function pass_named() {
     Assert::equals([1, 2], Routine::pass($f, ['a' => 1, 'b' => 2]));
   }
 
+  #[Test]
+  public function pass_named_null() {
+    $f= new ReflectionFunction(fn($a, $b) => null);
+    Assert::equals([null, 2], Routine::pass($f, ['a' => null, 'b' => 2]));
+  }
+
   #[Test]
   public function pass_named_out_of_order() {
     $f= new ReflectionFunction(fn($a, $b) => null);