[6.x] Implement withoutRelations method (#30802)

* Implement withoutRelations method

This will allow to unload all of the model's relations so it can be used, for example, to not overload queued jobs.

* Rework to clone object

src/Illuminate/Database/Eloquent/Concerns/HasRelationships.php

@@ -722,6 +722,30 @@ protected function newRelatedInstance($class)
         });
     }
 
+    /**
+     * Duplicate the instance and unset all the loaded relations.
+     *
+     * @return $this
+     */
+    public function withoutRelations()
+    {
+        $model = clone $this;
+
+        return $model->unsetRelations();
+    }
+
+    /**
+     * Unset all the loaded relations for the instance.
+     *
+     * @return $this
+     */
+    public function unsetRelations()
+    {
+        $this->relations = [];
+
+        return $this;
+    }
+
     /**
      * Get all the loaded relations for the instance.
      *

tests/Database/DatabaseEloquentRelationTest.php

@@ -234,6 +234,27 @@ public function testSettingMorphMapWithNumericKeys()
         Relation::morphMap([], false);
     }
 
+    public function testWithoutRelations()
+    {
+        $original = new EloquentNoTouchingModelStub;
+
+        $original->setRelation('foo', 'baz');
+
+        $this->assertEquals('baz', $original->getRelation('foo'));
+
+        $model = $original->withoutRelations();
+
+        $this->assertInstanceOf(EloquentNoTouchingModelStub::class, $model);
+        $this->assertTrue($original->relationLoaded('foo'));
+        $this->assertFalse($model->relationLoaded('foo'));
+
+        $model = $original->unsetRelations();
+
+        $this->assertInstanceOf(EloquentNoTouchingModelStub::class, $model);
+        $this->assertFalse($original->relationLoaded('foo'));
+        $this->assertFalse($model->relationLoaded('foo'));
+    }
+
     public function testMacroable()
     {
         Relation::macro('foo', function () {