On shipment deletion cascade slot deletion & remove orphan slots.

src/Migrations/Version20210915210206.php

@@ -0,0 +1,38 @@
+<?php
+
+/*
+ * This file is part of Monsieur Biz' Shipping Slot plugin for Sylius.
+ *
+ * (c) Monsieur Biz <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace MonsieurBiz\SyliusShippingSlotPlugin\Migrations;
+
+use Doctrine\DBAL\Schema\Schema;
+use Doctrine\Migrations\AbstractMigration;
+
+final class Version20210915210206 extends AbstractMigration
+{
+    public function getDescription(): string
+    {
+        return 'Cascade shipment deletion to slot deletion. Also remove slots without shipment.';
+    }
+
+    public function up(Schema $schema): void
+    {
+        $this->addSql('DELETE FROM monsieurbiz_shipping_slot_slot WHERE shipment_id IS NULL');
+        $this->addSql('ALTER TABLE monsieurbiz_shipping_slot_slot DROP FOREIGN KEY FK_3BD6F1F67BE036FC');
+        $this->addSql('ALTER TABLE monsieurbiz_shipping_slot_slot ADD CONSTRAINT FK_3BD6F1F67BE036FC FOREIGN KEY (shipment_id) REFERENCES sylius_shipment (id) ON DELETE CASCADE');
+    }
+
+    public function down(Schema $schema): void
+    {
+        $this->addSql('ALTER TABLE monsieurbiz_shipping_slot_slot DROP FOREIGN KEY FK_3BD6F1F67BE036FC');
+        $this->addSql('ALTER TABLE monsieurbiz_shipping_slot_slot ADD CONSTRAINT FK_3BD6F1F67BE036FC FOREIGN KEY (shipment_id) REFERENCES sylius_shipment (id) ON DELETE SET NULL');
+    }
+}

src/Resources/config/doctrine/Slot.orm.xml

@@ -16,7 +16,7 @@
             <gedmo:timestampable on="update"/>
         </field>
         <one-to-one field="shipment" target-entity="Sylius\Component\Shipping\Model\ShipmentInterface" inversed-by="slot">
-            <join-column name="shipment_id" referenced-column-name="id" nullable="true" on-delete="SET NULL" />
+            <join-column name="shipment_id" referenced-column-name="id" nullable="true" on-delete="CASCADE" />
         </one-to-one>
     </entity>
 </doctrine-mapping>