TASK: Make sure unset properties never leak into the node

The Node's properties must not reflect that a node's property was unset once.

Neos.ContentRepository.Core/Classes/Feature/NodeModification/Dto/SerializedPropertyValues.php

@@ -103,6 +103,9 @@ public function merge(self $other): self
 
     public function withoutUnsets(): self
     {
+        if (!in_array(UnsetPropertyValue::get(), $this->values, true)) {
+            return $this;
+        }
         $values = [];
         foreach ($this->values as $name => $serializedValue) {
             if ($serializedValue instanceof UnsetPropertyValue) {

Neos.ContentRepository.Core/Classes/Projection/ContentGraph/PropertyCollection.php

@@ -46,7 +46,9 @@ public function __construct(
         SerializedPropertyValues $serializedPropertyValues,
         PropertyConverter $propertyConverter
     ) {
-        $this->serializedPropertyValues = $serializedPropertyValues;
+        // we are not interested in the unset properties, as for the read model we make no difference between unset and never set.
+        // the projection should not need to preserve unset properties, but if it does, we filter them here.
+        $this->serializedPropertyValues = $serializedPropertyValues->withoutUnsets();
         $this->propertyConverter = $propertyConverter;
     }
 
@@ -62,7 +64,8 @@ public function offsetGet($offset): mixed
         }
 
         $serializedProperty = $this->serializedPropertyValues->getProperty($offset);
-        if ($serializedProperty === null || $serializedProperty instanceof UnsetPropertyValue) {
+        assert(!$serializedProperty instanceof UnsetPropertyValue); // not possible, see withoutUnsets
+        if ($serializedProperty === null) {
             return null;
         }
         return $this->deserializedPropertyValuesRuntimeCache[$offset] =

Neos.ContentRepository.Core/Tests/Unit/Feature/NodeModification/Dto/SerializedPropertyValuesTest.php

@@ -88,12 +88,17 @@ public function getPlainValuesReturnsNullForUnsetValues(): void
      */
     public function withoutUnsets(): void
     {
-        // the format which is implicitly used in the event log, due to json_serialize
+        // the format which should be used by the projections
         $propertyValues = SerializedPropertyValues::fromArray(['someProperty' => UnsetPropertyValue::get(), 'otherProperty' => SerializedPropertyValue::create('text', 'string'), 'reputation' => UnsetPropertyValue::get()]);
         self::assertEquals(
             SerializedPropertyValues::fromArray(['otherProperty' => SerializedPropertyValue::create('text', 'string')]),
             $propertyValues->withoutUnsets()
         );
-    }
 
+        $propertyValues = SerializedPropertyValues::fromArray(['someProperty' => SerializedPropertyValue::create('text', 'string'), 'otherProperty' => SerializedPropertyValue::create('text', 'string')]);
+        self::assertEquals(
+            $propertyValues,
+            $propertyValues->withoutUnsets()
+        );
+    }
 }

Neos.ContentRepository.Core/Tests/Unit/Projection/ContentGraph/PropertyCollectionTest.php

@@ -48,6 +48,7 @@ public function offsetGetReturnsNullIfPropertyDoesNotExist(): void
         $this->mockSerializer->expects($this->never())->method($this->anything());
         $collection = new PropertyCollection(SerializedPropertyValues::fromArray(['someProperty' => ['value' => 'some string', 'type' => 'string']]), $this->mockPropertyConverter);
         self::assertNull($collection['non-existing']);
+        self::assertFalse(isset($collection['non-existing']));
     }
 
     /**
@@ -58,6 +59,7 @@ public function offsetGetReturnsNullIfSerializedPropertyValueIsNull(): void
         $this->mockSerializer->expects($this->never())->method($this->anything());
         $collection = new PropertyCollection(SerializedPropertyValues::fromArray(['someProperty' => null]), $this->mockPropertyConverter);
         self::assertNull($collection['someProperty']);
+        self::assertFalse(isset($collection['someProperty']));
     }
 
     /**
@@ -68,6 +70,7 @@ public function offsetGetReturnsDeserializedValue(): void
         $this->mockSerializer->expects($this->once())->method('denormalize')->with('some string', 'string', null, [])->willReturn('some deserialized value');
         $collection = new PropertyCollection(SerializedPropertyValues::fromArray(['someProperty' => ['value' => 'some string', 'type' => 'string']]), $this->mockPropertyConverter);
         self::assertSame('some deserialized value', $collection['someProperty']);
+        self::assertTrue(isset($collection['someProperty']));
     }
 
     /**
@@ -107,7 +110,19 @@ public function serializedReturnsSerializedPropertyValues(): void
     {
         $serializedPropertyValues = SerializedPropertyValues::fromArray(['someProperty' => ['value' => 'some string', 'type' => 'string']]);
         $collection = new PropertyCollection($serializedPropertyValues, $this->mockPropertyConverter);
-        self::assertSame($serializedPropertyValues, $collection->serialized());
+        self::assertEquals($serializedPropertyValues, $collection->serialized());
     }
 
+    /**
+     * @test
+     */
+    public function serializedReturnsSerializedPropertyWithoutUnsetValues(): void
+    {
+        $serializedPropertyValues = SerializedPropertyValues::fromArray(['unsetProperty' => null, 'someProperty' => ['value' => 'some string', 'type' => 'string']]);
+        $collection = new PropertyCollection($serializedPropertyValues, $this->mockPropertyConverter);
+        self::assertEquals(
+            SerializedPropertyValues::fromArray(['someProperty' => ['value' => 'some string', 'type' => 'string']]),
+            $collection->serialized()
+        );
+    }
 }