Fix Belongs To Morphed behavior for custom ways

src/Relation/BelongsTo.php

@@ -91,6 +91,10 @@ public function queue(Pool $pool, Tuple $tuple): void
         if ($related instanceof ReferenceInterface && $related->hasValue()) {
             $related = $related->getValue();
             $state->setRelation($relName, $related);
+            if ($related === null) {
+                $state->setRelationStatus($this->getName(), RelationInterface::STATUS_RESOLVED);
+                return;
+            }
         }
         if ($related === null) {
             $this->setNullFromRelated($tuple, false);

src/Relation/Morphed/BelongsToMorphed.php

@@ -32,10 +32,8 @@ public function initReference(Node $node): ReferenceInterface
     {
         $scope = $this->getReferenceScope($node);
         $nodeData = $node->getData();
-        if ($scope === null || !isset($nodeData[$this->morphKey])) {
-            $result = new Reference($node->getRole(), []);
-            $result->setValue(null);
-            return $result;
+        if (!isset($nodeData[$this->morphKey], $scope)) {
+            return new EmptyReference('?', null);
         }
         // $scope[$this->morphKey] = $nodeData[$this->morphKey];
         $target = $nodeData[$this->morphKey];
@@ -48,7 +46,7 @@ public function prepare(Pool $pool, Tuple $tuple, mixed $related, bool $load = t
         parent::prepare($pool, $tuple, $related, $load);
         $related = $tuple->state->getRelation($this->getName());
 
-        if ($related === null) {
+        if ($related === null || $related instanceof EmptyReference) {
             return;
         }
 
@@ -70,8 +68,11 @@ protected function assertValid(Node $related): void
 
     protected function setNullFromRelated(Tuple $tuple, bool $isPreparing): void
     {
-        // Set morph key to null
-        $tuple->state->register($this->morphKey, null);
+        if ($tuple->node->getRelation($this->getName()) !== null) {
+            // Set morph key to null if the relation was changed to null
+            $tuple->state->register($this->morphKey, null);
+        }
+
         parent::setNullFromRelated($tuple, $isPreparing);
     }
 }

src/Select.php

@@ -210,7 +210,7 @@ public function offset(int $offset): self
      * Available DTO classes (one per relation type):
      * - {@see \Cycle\ORM\Select\Options\HasOneLoadOptions}
      * - {@see \Cycle\ORM\Select\Options\HasManyLoadOptions}
-     * - {@see \Cycle\ORM\Select\Options\BelongsToLoadOptions}
+     * - {@see \Cycle\ORM\Select\Options\BelongsToLoadOptions} applicable for both Belongs To and Refers To relations
      * - {@see \Cycle\ORM\Select\Options\ManyToManyLoadOptions}
      * - {@see \Cycle\ORM\Select\Options\MorphedHasOneLoadOptions}
      * - {@see \Cycle\ORM\Select\Options\MorphedHasManyLoadOptions}

tests/ORM/Fixtures/Image.php

@@ -8,6 +8,7 @@
 class Image
 {
     public $id;
+    public $parentType;
     public $parent;
     public $url;
 }

tests/ORM/Functional/Driver/Common/Relation/Morphed/BelongsToMorphedRelationTest.php

@@ -289,6 +289,7 @@ public function testSetNullShouldClearMorphType(): void
         $row = $this->getDatabase()->table('image')->select()->where('id', 1)->fetchAll();
         $this->assertSame('user', $row[0]['parent_type']);
         $this->assertNotNull($row[0]['parent_id']);
+        $this->save($c);
 
         $c->parent = null;
         $this->save($c);
@@ -318,6 +319,43 @@ public function testCreateWithoutParentShouldNotSetMorphType(): void
         $this->assertNull($row[0]['parent_type'], 'parent_type should be NULL for entity without parent');
     }
 
+    public function testUsingFactoryCreateWithoutRelatedButSetMorphTypeManually(): void
+    {
+        $schemaArray = $this->getNullableMorphedSchemaArray();
+        $this->orm = $this->orm->with(
+            schema: new Schema($schemaArray),
+        );
+
+        /** @var Image $c */
+        $c = $this->orm->make(Image::class);
+        $c->url = 'no-parent.png';
+        $c->parentType = 'user';
+
+        $this->save($c);
+
+        $row = $this->getDatabase()->table('image')->select()->where('id', $c->id)->fetchAll();
+        $this->assertNull($row[0]['parent_id'], 'parent_id should be NULL for entity without parent');
+        $this->assertSame('user', $row[0]['parent_type'], 'parent_type should be NULL for entity without parent');
+    }
+
+    public function testCreateWithoutRelatedButSetMorphTypeManually(): void
+    {
+        $schemaArray = $this->getNullableMorphedSchemaArray();
+        $this->orm = $this->orm->with(
+            schema: new Schema($schemaArray),
+        );
+
+        $c = new Image();
+        $c->url = 'no-parent.png';
+        $c->parentType = 'user';
+
+        $this->save($c);
+
+        $row = $this->getDatabase()->table('image')->select()->where('id', $c->id)->fetchAll();
+        $this->assertNull($row[0]['parent_id'], 'parent_id should be NULL for entity without parent');
+        $this->assertSame('user', $row[0]['parent_type'], 'parent_type should be NULL for entity without parent');
+    }
+
     public function testUpdateRelation(): void
     {
         $this->captureReadQueries();