Also make direct_edit.accessed nullable

Signed-off-by: Joas Schilling <coding@schilljs.com>

core/Migrations/Version18000Date20191014105105.php

@@ -82,7 +82,7 @@ class Version18000Date20191014105105 extends SimpleMigrationStep {
 			'unsigned' => true,
 		]);
 		$table->addColumn('accessed', Types::BOOLEAN, [
-			'notnull' => true,
+			'notnull' => false,
 			'default' => false
 		]);
 

core/Migrations/Version20000Date20201111081915.php

@@ -0,0 +1,61 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright Copyright (c) 2020 Joas Schilling <coding@schilljs.com>
+ *
+ * @author Joas Schilling <coding@schilljs.com>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * 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 <http://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace OC\Core\Migrations;
+
+use Closure;
+use OCP\DB\ISchemaWrapper;
+use OCP\Migration\IOutput;
+use OCP\Migration\SimpleMigrationStep;
+
+class Version20000Date20201111081915 extends SimpleMigrationStep {
+	/**
+	 * @param IOutput $output
+	 * @param Closure $schemaClosure The `\Closure` returns a `ISchemaWrapper`
+	 * @param array $options
+	 * @return null|ISchemaWrapper
+	 */
+	public function changeSchema(IOutput $output, Closure $schemaClosure, array $options): ?ISchemaWrapper {
+		/** @var ISchemaWrapper $schema */
+		$schema = $schemaClosure();
+
+		$result = $this->ensureColumnIsNullable($schema, 'direct_edit', 'accessed');
+
+		return $result ? $schema : null;
+	}
+
+	protected function ensureColumnIsNullable(ISchemaWrapper $schema, string $tableName, string $columnName): bool {
+		$table = $schema->getTable($tableName);
+		$column = $table->getColumn($columnName);
+
+		if ($column->getNotnull()) {
+			$column->setNotnull(false);
+			return true;
+		}
+
+		return false;
+	}
+}