Handle null as a falsy condition (#56612)

Author: negoziator

src/Illuminate/Validation/Rules/RequiredIf.php

@@ -18,10 +18,14 @@ class RequiredIf implements Stringable
     /**
      * Create a new required validation rule based on a condition.
      *
-     * @param  (\Closure(): bool)|bool  $condition
+     * @param  (\Closure(): bool)|bool|null  $condition
      */
     public function __construct($condition)
     {
+        if (is_null($condition)) {
+            $condition = false;
+        }
+
         if ($condition instanceof Closure || is_bool($condition)) {
             $this->condition = $condition;
         } else {

tests/Validation/ValidationRequiredIfTest.php

@@ -77,5 +77,10 @@ public function testRequiredIfRuleValidation()
 
         $v = new Validator($trans, ['x' => 'foo'], ['x' => ['string', $rule]]);
         $this->assertTrue($v->passes());
+
+        $rule = new RequiredIf(null);
+
+        $v = new Validator($trans, ['x' => 'foo'], ['x' => ['string', $rule]]);
+        $this->assertTrue($v->passes());
     }
 }