Skip xsi:type detection for elements without attributes

src/Encoder/XsiTypeEncoder.php

@@ -78,7 +78,9 @@ private function to(IsoInterface $innerIso, mixed $value): string
      */
     private function from(Context $context, IsoInterface $innerIso, ?Closure $detectEncoder, Element $value): mixed
     {
-        $iso = ($detectEncoder ? $detectEncoder($value->element()) : null)?->iso($context) ?? $innerIso;
+        // xsi:type is an attribute on the element itself, so an element without attributes cannot carry one.
+        $element = $value->element();
+        $iso = ($detectEncoder && $element->hasAttributes() ? $detectEncoder($element) : null)?->iso($context) ?? $innerIso;
 
         /** @psalm-suppress ImplicitToStringCast - Encoders accept string|Element in from() */
         return $iso->from($value);

tests/Unit/Encoder/XsiTypeEncoderTest.php

@@ -6,7 +6,9 @@
 use PHPUnit\Framework\Attributes\CoversClass;
 use PHPUnit\Framework\TestCase;
 use Soap\Encoding\Encoder\Context;
+use Soap\Encoding\Encoder\ElementEncoder;
 use Soap\Encoding\Encoder\Feature\DisregardXsiInformation;
+use Soap\Encoding\Encoder\SimpleType\StringTypeEncoder;
 use Soap\Encoding\Encoder\XmlEncoder;
 use Soap\Encoding\Encoder\XsiTypeEncoder;
 use Soap\Encoding\Test\Unit\ContextCreatorTrait;
@@ -64,6 +66,46 @@ public function test_it_ignores_xsi_type_for_encoders_that_disregard_it(): void
         static::assertSame('inner', $iso->from($this->element('<item ' . self::NAMESPACES . ' xsi:type="xsd:int">1</item>')));
     }
 
+    public function test_it_decodes_through_the_detected_xsi_type(): void
+    {
+        $actual = $this->decode(
+            '<hello xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:type="xsd:int">32</hello>'
+        );
+
+        static::assertSame(32, $actual);
+    }
+
+    public function test_it_decodes_an_element_without_attributes_through_the_inner_encoder(): void
+    {
+        $actual = $this->decode('<hello>32</hello>');
+
+        static::assertSame('32', $actual);
+    }
+
+    public function test_it_decodes_an_element_with_attributes_but_no_xsi_type_through_the_inner_encoder(): void
+    {
+        $actual = $this->decode('<hello xmlns:xsd="http://www.w3.org/2001/XMLSchema">32</hello>');
+
+        static::assertSame('32', $actual);
+    }
+
+    private function decode(string $xml): mixed
+    {
+        $encoder = new XsiTypeEncoder(new ElementEncoder(new StringTypeEncoder()));
+
+        return $encoder->iso($this->createStringContext())->from(Element::fromString($xml));
+    }
+
+    private function createStringContext(): Context
+    {
+        return self::createContext(
+            XsdType::guess('string')
+                ->withXmlNamespace('http://www.w3.org/2001/XMLSchema')
+                ->withXmlTargetNodeName('hello')
+                ->withMeta(static fn (TypeMeta $meta): TypeMeta => $meta->withIsQualified(true)->withIsSimple(true)->withIsElement(true))
+        );
+    }
+
     private function element(string $xml): Element
     {
         return Element::fromString($xml);