feat: allow merge values on relationships

Author: Ark4ne

src/Resources/Concerns/ConditionallyLoadsAttributes.php

@@ -2,6 +2,8 @@
 
 namespace Ark4ne\JsonApi\Resources\Concerns;
 
+use Ark4ne\JsonApi\Descriptors\Relations\Relation;
+use Ark4ne\JsonApi\Resources\Relationship;
 use Ark4ne\JsonApi\Support\Fields;
 use Ark4ne\JsonApi\Support\Includes;
 use Illuminate\Http\Request;
@@ -50,9 +52,27 @@ protected function whenIncluded(Request $request, string $type, mixed $value)
      */
     protected function applyWhen(bool $condition, iterable $data): MergeValue
     {
-        return new MergeValue($condition
-            ? $data
-            : collect($data)->map(fn() => new MissingValue)
-        );
+        if ($condition) {
+            return new MergeValue($data);
+        }
+
+        return new MergeValue(collect($data)->map(function ($raw) {
+            if ($raw instanceof Relationship) {
+                $relation = new class ($raw->getResource(), fn () => $raw) extends Relation {
+                    protected function value(\Closure $value): Relationship
+                    {
+                        return ($this->relation)();
+                    }
+                };
+
+                return $relation->when(false);
+            }
+
+            if ($raw instanceof Relation) {
+                return $raw->when(false);
+            }
+
+            return new MissingValue();
+        }));
     }
 }

src/Resources/Concerns/Relationships.php

@@ -10,7 +10,7 @@
 
 trait Relationships
 {
-    use Resolver;
+    use PrepareData, Resolver;
 
     /**
      * @see https://jsonapi.org/format/#document-resource-object-relationships
@@ -43,6 +43,7 @@ private function requestedRelationships(Request $request): array
     {
         $relations = [];
         $relationships = $this->toRelationships($request);
+        $relationships = $this->mergeValues($relationships);
         $relationships = $this->resolveValues($request, $relationships);
         $relationships = $this->filter($relationships);
 

tests/Unit/Resources/Concerns/ConditionallyLoadsAttributesTest.php

@@ -2,6 +2,8 @@
 
 namespace Test\Unit\Resources\Concerns;
 
+use Ark4ne\JsonApi\Descriptors\Relations\RelationOne;
+use Ark4ne\JsonApi\Descriptors\Values\ValueMixed;
 use Ark4ne\JsonApi\Resources\Concerns\ConditionallyLoadsAttributes;
 use Illuminate\Http\Request;
 use Illuminate\Http\Resources\Json\JsonResource;
@@ -80,5 +82,17 @@ public function testApplyWhen()
             'present.1' => 'abc',
             'present.2' => 123,
         ]), $actual);
+        $actual = Reflect::invoke($stub, 'applyWhen', true, [
+            'present.1' => (new ValueMixed(fn() => 'abc')),
+            'present.2' => (new ValueMixed(fn() => 123)),
+            'present.3' => (new RelationOne('present', fn() => 'abc')),
+            'present.4' => (new RelationOne('present', fn() => 123)),
+        ]);
+        $this->assertEquals(new MergeValue([
+            'present.1' => (new ValueMixed(fn() => 'abc')),
+            'present.2' => (new ValueMixed(fn() => 123)),
+            'present.3' => (new RelationOne('present', fn() => 'abc')),
+            'present.4' => (new RelationOne('present', fn() => 123)),
+        ]), $actual);
     }
 }