update validator to enable attribute support

composer.json

@@ -13,7 +13,7 @@
     "require": {
         "php": ">=8.0",
         "league/tactician": "^1.0",
-        "symfony/validator": "^5.1"
+        "symfony/validator": "^5.1|^6.0"
     },
     "autoload": {
         "psr-4": {

tests/Fixtures/AttributeReaderCommand.php

@@ -0,0 +1,21 @@
+<?php
+
+namespace DMT\Test\CommandBus\Fixtures;
+
+use Symfony\Component\Validator\Constraints as Assert;
+
+class AttributeReaderCommand
+{
+    #[Assert\NotNull()]
+    protected ?string $prop = null;
+
+    public function getProp(): ?string
+    {
+        return $this->prop;
+    }
+
+    public function setProp($prop): void
+    {
+        $this->prop = $prop;
+    }
+}

tests/Validator/ValidationMiddlewareTest.php

@@ -5,6 +5,7 @@
 use DMT\CommandBus\Validator\ValidationException;
 use DMT\CommandBus\Validator\ValidationMiddleware;
 use DMT\Test\CommandBus\Fixtures\AnnotationReaderCommand;
+use DMT\Test\CommandBus\Fixtures\AttributeReaderCommand;
 use DMT\Test\CommandBus\Fixtures\ClassMetadataCommand;
 use PHPUnit\Framework\Attributes\DataProvider;
 use PHPUnit\Framework\TestCase;
@@ -59,6 +60,15 @@ public function testAnnotationReaderValidator(): void
         $middleware->execute(new AnnotationReaderCommand(), 'gettype');
     }
 
+    public function testAttributeReaderValidator(): void
+    {
+        $this->expectException(ValidationException::class);
+        $this->expectExceptionMessageMatches("~Invalid command .* given~");
+
+        $middleware = new ValidationMiddleware();
+        $middleware->execute(new AttributeReaderCommand(), 'gettype');
+    }
+
     #[DataProvider(methodName: "provideConstraintViolations")]
     public function testInvalidCommand(ConstraintViolationList $violations): void
     {