Fix: WhenMissing doesn't work in Nested rules.

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## 2.3.1 under development
 
+- Bug #750: Fix `WhenMissing` not working in nested rules (@Enjoyzz)
 - Enh #770: Allow use callable rules into `Nested` (@Enjoyzz)
 - Bug #751: Fix incorrect `Nested` rule processing within `Each` (@Enjoyzz)
 

src/Rule/NestedHandler.php

@@ -93,7 +93,10 @@
             } else {
                 $valuePathList = StringHelper::parsePath($valuePath);
                 $property = end($valuePathList);
-                $itemResult = $context->validate([$property => $validatedValue], [$property => $rules]);
+                $itemResult = $context->validate(
+                    ArrayHelper::keyExists($data, $valuePathList) ? [$property => $validatedValue] : [],
+                    [$property => $rules]
+                );
             }
 
             if ($itemResult->isValid()) {

tests/Rule/NestedTest.php

@@ -11,6 +11,7 @@
 use stdClass;
 use Yiisoft\Validator\DataSet\ObjectDataSet;
 use Yiisoft\Validator\DataSetInterface;
+use Yiisoft\Validator\EmptyCondition\WhenMissing;
 use Yiisoft\Validator\Error;
 use Yiisoft\Validator\Helper\RulesDumper;
 use Yiisoft\Validator\PostValidationHookInterface;
@@ -29,6 +30,7 @@
 use Yiisoft\Validator\Rule\Regex;
 use Yiisoft\Validator\Rule\Required;
 use Yiisoft\Validator\Rule\StringValue;
+use Yiisoft\Validator\Rule\Type\BooleanType;
 use Yiisoft\Validator\RuleInterface;
 use Yiisoft\Validator\RulesProviderInterface;
 use Yiisoft\Validator\Tests\Rule\Base\DifferentRuleInHandlerTestTrait;
@@ -1259,7 +1261,7 @@ public function hasProperty(string $property): bool
                     ReflectionProperty::IS_PUBLIC,
                 ),
                 new Nested(['value' => new Required()]),
-                ['value' => ['Value cannot be blank.']],
+                ['value' => ['Value not passed.']],
             ],
             'nested context' => [
                 [
@@ -1576,4 +1578,115 @@ public function testExampleFromIssue751()
         $this->assertFalse($result->isValid());
         $this->assertSame(['array_of_a.0.id' => ['Id cannot be blank.']], $result->getErrorMessagesIndexedByPath());
     }
+
+    /**
+     * @see https://github.com/yiisoft/validator/issues/750
+     */
+    public function testNestedRulesWithWhenMissing(): void
+    {
+        $rules = [
+            'regulations' => new Nested(
+                rules: [
+                    'is_one_time' => new BooleanType(
+                        skipOnEmpty: new WhenMissing()
+                    ),
+                ],
+                skipOnEmpty: new WhenMissing()
+            ),
+        ];
+
+        $data = [
+            'service' => 'service',
+            'amount' => 200,
+        ];
+
+        $result = (new Validator())->validate($data, $rules);
+        $this->assertTrue($result->isValid());
+
+        $data = [
+            'service' => 'service',
+            'amount' => 200,
+            'regulations' => [],
+        ];
+
+        $result = (new Validator())->validate($data, $rules);
+        $this->assertTrue($result->isValid());
+
+        $data = [
+            'service' => 'service',
+            'amount' => 200,
+            'regulations' => [
+                'is_one_time' => null,
+            ],
+        ];
+
+        $result = (new Validator())->validate($data, $rules);
+        $this->assertFalse($result->isValid());
+
+        $data = [
+            'service' => 'service',
+            'amount' => 200,
+            'regulations' => [
+                'is_one_time' => true,
+            ],
+        ];
+
+        $result = (new Validator())->validate($data, $rules);
+        $this->assertTrue($result->isValid());
+    }
+
+    public function testNestedRulesWithWhenMissingAndNullableField(): void
+    {
+        $rules = [
+            'regulations' => new Nested(
+                rules: [
+                    'is_one_time' => new Callback(
+                        callback: static function (mixed $value): Result {
+                            $result = new Result();
+                            if (!in_array(get_debug_type($value), ['bool', 'null'], true)) {
+                                $result->addError('Value must be a boolean or null.');
+                            }
+                            return $result;
+                        },
+                        skipOnEmpty: new WhenMissing()
+                    ),
+                ],
+                skipOnEmpty: new WhenMissing()
+            ),
+        ];
+
+        $data = [
+            'service' => 'service',
+            'amount' => 200,
+            'regulations' => [
+                'is_one_time' => null,
+            ],
+        ];
+
+        $result = (new Validator())->validate($data, $rules);
+        $this->assertTrue($result->isValid());
+
+
+        $data = [
+            'service' => 'service',
+            'amount' => 200,
+            'regulations' => [
+                'is_one_time' => true,
+            ],
+        ];
+
+        $result = (new Validator())->validate($data, $rules);
+        $this->assertTrue($result->isValid());
+
+        $data = [
+            'service' => 'service',
+            'amount' => 200,
+            'regulations' => [
+                'is_one_time' => '',
+            ],
+        ];
+
+        $result = (new Validator())->validate($data, $rules);
+        $this->assertFalse($result->isValid());
+    }
 }