Use new UniqueObjectCollection constraint to ensure that BOM entries does not contain duplicate items

src/Validator/UniqueValidatableInterface.php

@@ -0,0 +1,32 @@
+<?php
+/*
+ * This file is part of Part-DB (https://github.com/Part-DB/Part-DB-symfony).
+ *
+ *  Copyright (C) 2019 - 2023 Jan Böhmer (https://github.com/jbtronics)
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU Affero General Public License as published
+ *  by the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU Affero General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Affero General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+namespace App\Validator;
+
+interface UniqueValidatableInterface
+{
+    /**
+     * This method should return an array of fields that should be used to compare the objects for the UniqueObjectCollection constraint.
+     * All instances of the same class should return the same fields.
+     * The value must be a comparable value (e.g. string, int, float, bool, null).
+     * @return array An array of the form ['field1' => 'value1', 'field2' => 'value2', ...]
+     */
+    public function getComparableFields(): array;
+}