support multiple fields to validateDifferent (#19637)

Author: tillkruss

src/Illuminate/Validation/Concerns/ValidatesAttributes.php

@@ -375,9 +375,15 @@ protected function validateDifferent($attribute, $value, $parameters)
     {
         $this->requireParameterCount(1, $parameters, 'different');
 
-        $other = Arr::get($this->data, $parameters[0]);
+        foreach ($parameters as $parameter) {
+            $other = Arr::get($this->data, $parameter);
+
+            if (is_null($other) || $value === $other) {
+                return false;
+            }
+        }
 
-        return isset($other) && $value !== $other;
+        return true;
     }
 
     /**

tests/Validation/ValidationValidatorTest.php

@@ -1012,6 +1012,15 @@ public function testValidateDifferent()
 
         $v = new Validator($trans, ['foo' => '1e2', 'baz' => '100'], ['foo' => 'Different:baz']);
         $this->assertTrue($v->passes());
+
+        $v = new Validator($trans, ['foo' => 'bar', 'fuu' => 'baa', 'baz' => 'boom'], ['foo' => 'Different:fuu,baz']);
+        $this->assertTrue($v->passes());
+
+        $v = new Validator($trans, ['foo' => 'bar', 'baz' => 'boom'], ['foo' => 'Different:fuu,baz']);
+        $this->assertFalse($v->passes());
+
+        $v = new Validator($trans, ['foo' => 'bar', 'fuu' => 'bar', 'baz' => 'boom'], ['foo' => 'Different:fuu,baz']);
+        $this->assertFalse($v->passes());
     }
 
     public function testValidateAccepted()