Merge pull request #19890 from nextcloud/enh/comments-reference-id

Add optional comments reference_id

17 files changed, 344 insertions, 31 deletions

diff --git a/apps/dav/tests/unit/Comments/CommentsNodeTest.php b/apps/dav/tests/unit/Comments/CommentsNodeTest.php
index 0555d09379c..a219b0a5c74 100644
--- a/apps/dav/tests/unit/Comments/CommentsNodeTest.php
+++ b/apps/dav/tests/unit/Comments/CommentsNodeTest.php
@@ -108,7 +108,7 @@ class CommentsNodeTest extends \Test\TestCase {
 		$this->node->delete();
 	}
 
-	
+
 	public function testDeleteForbidden() {
 		$this->expectException(\Sabre\DAV\Exception\Forbidden::class);
 
@@ -150,7 +150,7 @@ class CommentsNodeTest extends \Test\TestCase {
 		$this->assertSame($this->node->getName(), $id);
 	}
 
-	
+
 	public function testSetName() {
 		$this->expectException(\Sabre\DAV\Exception\MethodNotAllowed::class);
 
@@ -195,7 +195,7 @@ class CommentsNodeTest extends \Test\TestCase {
 		$this->assertTrue($this->node->updateComment($msg));
 	}
 
-	
+
 	public function testUpdateCommentLogException() {
 		$this->expectException(\Exception::class);
 		$this->expectExceptionMessage('buh!');
@@ -236,7 +236,7 @@ class CommentsNodeTest extends \Test\TestCase {
 		$this->node->updateComment($msg);
 	}
 
-	
+
 	public function testUpdateCommentMessageTooLongException() {
 		$this->expectException(\Sabre\DAV\Exception\BadRequest::class);
 		$this->expectExceptionMessage('Message exceeds allowed character limit of');
@@ -275,7 +275,7 @@ class CommentsNodeTest extends \Test\TestCase {
 		$this->node->updateComment('foo');
 	}
 
-	
+
 	public function testUpdateForbiddenByUser() {
 		$this->expectException(\Sabre\DAV\Exception\Forbidden::class);
 
@@ -310,7 +310,7 @@ class CommentsNodeTest extends \Test\TestCase {
 		$this->node->updateComment($msg);
 	}
 
-	
+
 	public function testUpdateForbiddenByType() {
 		$this->expectException(\Sabre\DAV\Exception\Forbidden::class);
 
@@ -340,7 +340,7 @@ class CommentsNodeTest extends \Test\TestCase {
 		$this->node->updateComment($msg);
 	}
 
-	
+
 	public function testUpdateForbiddenByNotLoggedIn() {
 		$this->expectException(\Sabre\DAV\Exception\Forbidden::class);
 
@@ -403,6 +403,7 @@ class CommentsNodeTest extends \Test\TestCase {
 			$ns . 'latestChildDateTime' => new \DateTime('2016-01-12 18:48:00'),
 			$ns . 'objectType' => 'files',
 			$ns . 'objectId' => '1848',
+			$ns . 'referenceId' => 'ref',
 			$ns . 'isUnread' => null,
 		];
 
@@ -469,6 +470,10 @@ class CommentsNodeTest extends \Test\TestCase {
 			->method('getObjectId')
 			->willReturn($expected[$ns . 'objectId']);
 
+		$this->comment->expects($this->once())
+			->method('getReferenceId')
+			->willReturn($expected[$ns . 'referenceId']);
+
 		$user = $this->getMockBuilder(IUser::class)
 			->disableOriginalConstructor()
 			->getMock();
@@ -484,7 +489,7 @@ class CommentsNodeTest extends \Test\TestCase {
 		$properties = $this->node->getProperties(null);
 
 		foreach($properties as $name => $value) {
-			$this->assertTrue(array_key_exists($name, $expected));
+			$this->assertArrayHasKey($name, $expected);
 			$this->assertSame($expected[$name], $value);
 			unset($expected[$name]);
 		}
diff --git a/apps/settings/lib/Controller/CheckSetupController.php b/apps/settings/lib/Controller/CheckSetupController.php
index 04711cf5308..6f3bb539eff 100644
--- a/apps/settings/lib/Controller/CheckSetupController.php
+++ b/apps/settings/lib/Controller/CheckSetupController.php
@@ -46,6 +46,7 @@ use GuzzleHttp\Exception\ClientException;
 use OC;
 use OC\AppFramework\Http;
 use OC\DB\Connection;
+use OC\DB\MissingColumnInformation;
 use OC\DB\MissingIndexInformation;
 use OC\DB\SchemaWrapper;
 use OC\IntegrityCheck\Checker;
@@ -445,6 +446,15 @@ Raw output
 		return $indexInfo->getListOfMissingIndexes();
 	}
 
+	protected function hasMissingColumns(): array {
+		$indexInfo = new MissingColumnInformation();
+		// Dispatch event so apps can also hint for pending index updates if needed
+		$event = new GenericEvent($indexInfo);
+		$this->dispatcher->dispatch(IDBConnection::CHECK_MISSING_COLUMNS_EVENT, $event);
+
+		return $indexInfo->getListOfMissingColumns();
+	}
+
 	protected function isSqliteUsed() {
 		return strpos($this->config->getSystemValue('dbtype'), 'sqlite') !== false;
 	}
@@ -693,6 +703,7 @@ Raw output
 				'isSettimelimitAvailable' => $this->isSettimelimitAvailable(),
 				'hasFreeTypeSupport' => $this->hasFreeTypeSupport(),
 				'missingIndexes' => $this->hasMissingIndexes(),
+				'missingColumns' => $this->hasMissingColumns(),
 				'isSqliteUsed' => $this->isSqliteUsed(),
 				'databaseConversionDocumentation' => $this->urlGenerator->linkToDocs('admin-db-conversion'),
 				'isPHPMailerUsed' => $this->isPHPMailerUsed(),
diff --git a/apps/settings/tests/Controller/CheckSetupControllerTest.php b/apps/settings/tests/Controller/CheckSetupControllerTest.php
index 5e59bfe353a..c15f3b8f23a 100644
--- a/apps/settings/tests/Controller/CheckSetupControllerTest.php
+++ b/apps/settings/tests/Controller/CheckSetupControllerTest.php
@@ -583,6 +583,7 @@ class CheckSetupControllerTest extends TestCase {
 				'isSqliteUsed' => false,
 				'databaseConversionDocumentation' => 'http://docs.example.org/server/go.php?to=admin-db-conversion',
 				'missingIndexes' => [],
+				'missingColumns' => [],
 				'isPHPMailerUsed' => false,
 				'mailSettingsDocumentation' => 'https://server/index.php/settings/admin',
 				'isMemoryLimitSufficient' => true,
diff --git a/core/Application.php b/core/Application.php
index c1ac8971532..15246c9c76c 100644
--- a/core/Application.php
+++ b/core/Application.php
@@ -39,6 +39,7 @@ use OC\Authentication\Listeners\RemoteWipeNotificationsListener;
 use OC\Authentication\Listeners\UserDeletedStoreCleanupListener;
 use OC\Authentication\Notifications\Notifier as AuthenticationNotifier;
 use OC\Core\Notification\RemoveLinkSharesNotifier;
+use OC\DB\MissingColumnInformation;
 use OC\DB\MissingIndexInformation;
 use OC\DB\SchemaWrapper;
 use OCP\AppFramework\App;
@@ -167,6 +168,23 @@ class Application extends App {
 			}
 		);
 
+		$eventDispatcher->addListener(IDBConnection::CHECK_MISSING_COLUMNS_EVENT,
+			function (GenericEvent $event) use ($container) {
+				/** @var MissingColumnInformation $subject */
+				$subject = $event->getSubject();
+
+				$schema = new SchemaWrapper($container->query(IDBConnection::class));
+
+				if ($schema->hasTable('comments')) {
+					$table = $schema->getTable('comments');
+
+					if (!$table->hasColumn('reference_id')) {
+						$subject->addHintForMissingColumn($table->getName(), 'reference_id');
+					}
+				}
+			}
+		);
+
 		$eventDispatcher->addServiceListener(RemoteWipeStarted::class, RemoteWipeActivityListener::class);
 		$eventDispatcher->addServiceListener(RemoteWipeStarted::class, RemoteWipeNotificationsListener::class);
 		$eventDispatcher->addServiceListener(RemoteWipeStarted::class, RemoteWipeEmailListener::class);
diff --git a/core/Command/Db/AddMissingColumns.php b/core/Command/Db/AddMissingColumns.php
new file mode 100644
index 00000000000..4672770c6af
--- /dev/null
+++ b/core/Command/Db/AddMissingColumns.php
@@ -0,0 +1,105 @@
+<?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\Command\Db;
+
+use OC\DB\SchemaWrapper;
+use OCP\IDBConnection;
+use Symfony\Component\Console\Command\Command;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Output\OutputInterface;
+use Symfony\Component\EventDispatcher\EventDispatcherInterface;
+use Symfony\Component\EventDispatcher\GenericEvent;
+
+/**
+ * Class AddMissingColumns
+ *
+ * if you added a new lazy column to the database, this is the right place to add
+ * your update routine for existing instances
+ *
+ * @package OC\Core\Command\Db
+ */
+class AddMissingColumns extends Command {
+
+	/** @var IDBConnection */
+	private $connection;
+
+	/** @var EventDispatcherInterface */
+	private $dispatcher;
+
+	public function __construct(IDBConnection $connection, EventDispatcherInterface $dispatcher) {
+		parent::__construct();
+
+		$this->connection = $connection;
+		$this->dispatcher = $dispatcher;
+	}
+
+	protected function configure() {
+		$this
+			->setName('db:add-missing-columns')
+			->setDescription('Add missing optional columns to the database tables');
+	}
+
+	protected function execute(InputInterface $input, OutputInterface $output) {
+		$this->addCoreColumns($output);
+
+		// Dispatch event so apps can also update columns if needed
+		$event = new GenericEvent($output);
+		$this->dispatcher->dispatch(IDBConnection::ADD_MISSING_COLUMNS_EVENT, $event);
+	}
+
+	/**
+	 * add missing indices to the share table
+	 *
+	 * @param OutputInterface $output
+	 * @throws \Doctrine\DBAL\Schema\SchemaException
+	 */
+	private function addCoreColumns(OutputInterface $output) {
+
+		$output->writeln('<info>Check columns of the comments table.</info>');
+
+		$schema = new SchemaWrapper($this->connection);
+		$updated = false;
+
+		if ($schema->hasTable('comments')) {
+			$table = $schema->getTable('comments');
+			if (!$table->hasColumn('reference_id')) {
+				$output->writeln('<info>Adding additional reference_id column to the comments table, this can take some time...</info>');
+				$table->addColumn('reference_id', 'string', [
+					'notnull' => false,
+					'length' => 64,
+				]);
+				$this->connection->migrateToSchema($schema->getWrappedSchema());
+				$updated = true;
+				$output->writeln('<info>Comments table updated successfully.</info>');
+			}
+		}
+
+		if (!$updated) {
+			$output->writeln('<info>Done.</info>');
+		}
+	}
+}
diff --git a/core/Command/Db/AddMissingIndices.php b/core/Command/Db/AddMissingIndices.php
index b1763575ccf..924c2af05c0 100644
--- a/core/Command/Db/AddMissingIndices.php
+++ b/core/Command/Db/AddMissingIndices.php
@@ -43,7 +43,7 @@ use Symfony\Component\EventDispatcher\GenericEvent;
  * Class AddMissingIndices
  *
  * if you added any new indices to the database, this is the right place to add
- * it your update routine for existing instances
+ * your update routine for existing instances
  *
  * @package OC\Core\Command\Db
  */
diff --git a/core/Migrations/Version13000Date20170718121200.php b/core/Migrations/Version13000Date20170718121200.php
index e9f376a7e42..757697e7e90 100644
--- a/core/Migrations/Version13000Date20170718121200.php
+++ b/core/Migrations/Version13000Date20170718121200.php
@@ -769,6 +769,10 @@ class Version13000Date20170718121200 extends SimpleMigrationStep {
 				'length' => 64,
 				'default' => '',
 			]);
+			$table->addColumn('reference_id', 'string', [
+				'notnull' => false,
+				'length' => 64,
+			]);
 			$table->setPrimaryKey(['id']);
 			$table->addIndex(['parent_id'], 'comments_parent_id_index');
 			$table->addIndex(['topmost_parent_id'], 'comments_topmost_parent_id_idx');
diff --git a/core/js/setupchecks.js b/core/js/setupchecks.js
index 12d1104a632..2e94c82486c 100644
--- a/core/js/setupchecks.js
+++ b/core/js/setupchecks.js
@@ -357,6 +357,21 @@
 							type: OC.SetupChecks.MESSAGE_TYPE_INFO
 						})
 					}
+					if (data.missingColumns.length > 0) {
+						var listOfMissingColumns = "";
+						data.missingColumns.forEach(function(element){
+							listOfMissingColumns += "<li>";
+							listOfMissingColumns += t('core', 'Missing optional column "{columnName}" in table "{tableName}".', element);
+							listOfMissingColumns += "</li>";
+						});
+						messages.push({
+							msg: t(
+								'core',
+								'The database is missing some optional columns. Due to the fact that adding columns on big tables could take some time they were not added automatically when they can be optional. By running "occ db:add-missing-columns" those missing columns could be added manually while the instance keeps running. Once the columns are added some features might improve responsiveness or usability.'
+							) + "<ul>" + listOfMissingColumns + "</ul>",
+							type: OC.SetupChecks.MESSAGE_TYPE_INFO
+						})
+					}
 					if (data.recommendedPHPModules.length > 0) {
 						var listOfRecommendedPHPModules = "";
 						data.recommendedPHPModules.forEach(function(element){
diff --git a/core/js/tests/specs/setupchecksSpec.js b/core/js/tests/specs/setupchecksSpec.js
index 5e93cbf7bdf..f4c81c6bf78 100644
--- a/core/js/tests/specs/setupchecksSpec.js
+++ b/core/js/tests/specs/setupchecksSpec.js
@@ -240,6 +240,7 @@ describe('OC.SetupChecks tests', function() {
 					isSettimelimitAvailable: true,
 					hasFreeTypeSupport: true,
 					missingIndexes: [],
+					missingColumns: [],
 					cronErrors: [],
 					cronInfo: {
 						diffInSeconds: 0
@@ -293,6 +294,7 @@ describe('OC.SetupChecks tests', function() {
 					isSettimelimitAvailable: true,
 					hasFreeTypeSupport: true,
 					missingIndexes: [],
+					missingColumns: [],
 					cronErrors: [],
 					cronInfo: {
 						diffInSeconds: 0
@@ -347,6 +349,7 @@ describe('OC.SetupChecks tests', function() {
 					isSettimelimitAvailable: true,
 					hasFreeTypeSupport: true,
 					missingIndexes: [],
+					missingColumns: [],
 					cronErrors: [],
 					cronInfo: {
 						diffInSeconds: 0
@@ -399,6 +402,7 @@ describe('OC.SetupChecks tests', function() {
 					isSettimelimitAvailable: true,
 					hasFreeTypeSupport: true,
 					missingIndexes: [],
+					missingColumns: [],
 					cronErrors: [],
 					cronInfo: {
 						diffInSeconds: 0
@@ -449,6 +453,7 @@ describe('OC.SetupChecks tests', function() {
 					isSettimelimitAvailable: true,
 					hasFreeTypeSupport: true,
 					missingIndexes: [],
+					missingColumns: [],
 					cronErrors: [],
 					cronInfo: {
 						diffInSeconds: 0
@@ -499,6 +504,7 @@ describe('OC.SetupChecks tests', function() {
 					isSettimelimitAvailable: true,
 					hasFreeTypeSupport: true,
 					missingIndexes: [],
+					missingColumns: [],
 					cronErrors: [],
 					cronInfo: {
 						diffInSeconds: 0
@@ -551,6 +557,7 @@ describe('OC.SetupChecks tests', function() {
 					isSettimelimitAvailable: true,
 					hasFreeTypeSupport: true,
 					missingIndexes: [],
+					missingColumns: [],
 					cronErrors: [],
 					cronInfo: {
 						diffInSeconds: 0
@@ -601,6 +608,7 @@ describe('OC.SetupChecks tests', function() {
 					isSettimelimitAvailable: false,
 					hasFreeTypeSupport: true,
 					missingIndexes: [],
+					missingColumns: [],
 					cronErrors: [],
 					cronInfo: {
 						diffInSeconds: 0
@@ -651,6 +659,7 @@ describe('OC.SetupChecks tests', function() {
 					isSettimelimitAvailable: true,
 					hasFreeTypeSupport: true,
 					missingIndexes: [],
+					missingColumns: [],
 					cronErrors: [],
 					cronInfo: {
 						diffInSeconds: 0
@@ -722,6 +731,7 @@ describe('OC.SetupChecks tests', function() {
 					isSettimelimitAvailable: true,
 					hasFreeTypeSupport: true,
 					missingIndexes: [],
+					missingColumns: [],
 					cronErrors: [],
 					cronInfo: {
 						diffInSeconds: 0
@@ -773,6 +783,7 @@ describe('OC.SetupChecks tests', function() {
 					isSettimelimitAvailable: true,
 					hasFreeTypeSupport: true,
 					missingIndexes: [],
+					missingColumns: [],
 					cronErrors: [],
 					cronInfo: {
 						diffInSeconds: 0
@@ -824,6 +835,7 @@ describe('OC.SetupChecks tests', function() {
 					isSettimelimitAvailable: true,
 					hasFreeTypeSupport: true,
 					missingIndexes: [],
+					missingColumns: [],
 					cronErrors: [],
 					cronInfo: {
 						diffInSeconds: 0
@@ -875,6 +887,7 @@ describe('OC.SetupChecks tests', function() {
 					isSettimelimitAvailable: true,
 					hasFreeTypeSupport: false,
 					missingIndexes: [],
+					missingColumns: [],
 					cronErrors: [],
 					cronInfo: {
 						diffInSeconds: 0
@@ -925,6 +938,7 @@ describe('OC.SetupChecks tests', function() {
 					isSettimelimitAvailable: true,
 					hasFreeTypeSupport: true,
 					missingIndexes: [],
+					missingColumns: [],
 					cronErrors: [],
 					cronInfo: {
 						diffInSeconds: 0
@@ -975,6 +989,7 @@ describe('OC.SetupChecks tests', function() {
 					isSettimelimitAvailable: true,
 					hasFreeTypeSupport: true,
 					missingIndexes: [],
+					missingColumns: [],
 					cronErrors: [],
 					cronInfo: {
 						diffInSeconds: 0
@@ -1026,6 +1041,7 @@ describe('OC.SetupChecks tests', function() {
 					isSettimelimitAvailable: true,
 					hasFreeTypeSupport: true,
 					missingIndexes: [],
+					missingColumns: [],
 					cronErrors: [],
 					cronInfo: {
 						diffInSeconds: 0
diff --git a/core/register_command.php b/core/register_command.php
index efa3146c492..e355d1429c1 100644
--- a/core/register_command.php
+++ b/core/register_command.php
@@ -99,6 +99,7 @@ if (\OC::$server->getConfig()->getSystemValue('installed', false)) {
 	$application->add(new OC\Core\Command\Db\ConvertMysqlToMB4(\OC::$server->getConfig(), \OC::$server->getDatabaseConnection(), \OC::$server->getURLGenerator(), \OC::$server->getLogger()));
 	$application->add(new OC\Core\Command\Db\ConvertFilecacheBigInt(\OC::$server->getDatabaseConnection()));
 	$application->add(new OC\Core\Command\Db\AddMissingIndices(\OC::$server->getDatabaseConnection(), \OC::$server->getEventDispatcher()));
+	$application->add(new OC\Core\Command\Db\AddMissingColumns(\OC::$server->getDatabaseConnection(), \OC::$server->getEventDispatcher()));
 	$application->add(new OC\Core\Command\Db\Migrations\StatusCommand(\OC::$server->getDatabaseConnection()));
 	$application->add(new OC\Core\Command\Db\Migrations\MigrateCommand(\OC::$server->getDatabaseConnection()));
 	$application->add(new OC\Core\Command\Db\Migrations\GenerateCommand(\OC::$server->getDatabaseConnection(), \OC::$server->getAppManager()));
diff --git a/lib/composer/composer/autoload_classmap.php b/lib/composer/composer/autoload_classmap.php
index 4cf77a34a5c..9a1f5befb4d 100644
--- a/lib/composer/composer/autoload_classmap.php
+++ b/lib/composer/composer/autoload_classmap.php
@@ -738,6 +738,7 @@ return array(
     'OC\\Core\\Command\\Config\\System\\DeleteConfig' => $baseDir . '/core/Command/Config/System/DeleteConfig.php',
     'OC\\Core\\Command\\Config\\System\\GetConfig' => $baseDir . '/core/Command/Config/System/GetConfig.php',
     'OC\\Core\\Command\\Config\\System\\SetConfig' => $baseDir . '/core/Command/Config/System/SetConfig.php',
+    'OC\\Core\\Command\\Db\\AddMissingColumns' => $baseDir . '/core/Command/Db/AddMissingColumns.php',
     'OC\\Core\\Command\\Db\\AddMissingIndices' => $baseDir . '/core/Command/Db/AddMissingIndices.php',
     'OC\\Core\\Command\\Db\\ConvertFilecacheBigInt' => $baseDir . '/core/Command/Db/ConvertFilecacheBigInt.php',
     'OC\\Core\\Command\\Db\\ConvertMysqlToMB4' => $baseDir . '/core/Command/Db/ConvertMysqlToMB4.php',
@@ -873,6 +874,7 @@ return array(
     'OC\\DB\\MigrationException' => $baseDir . '/lib/private/DB/MigrationException.php',
     'OC\\DB\\MigrationService' => $baseDir . '/lib/private/DB/MigrationService.php',
     'OC\\DB\\Migrator' => $baseDir . '/lib/private/DB/Migrator.php',
+    'OC\\DB\\MissingColumnInformation' => $baseDir . '/lib/private/DB/MissingColumnInformation.php',
     'OC\\DB\\MissingIndexInformation' => $baseDir . '/lib/private/DB/MissingIndexInformation.php',
     'OC\\DB\\MySQLMigrator' => $baseDir . '/lib/private/DB/MySQLMigrator.php',
     'OC\\DB\\MySqlTools' => $baseDir . '/lib/private/DB/MySqlTools.php',
diff --git a/lib/composer/composer/autoload_static.php b/lib/composer/composer/autoload_static.php
index c3a1a6a6264..318888bd434 100644
--- a/lib/composer/composer/autoload_static.php
+++ b/lib/composer/composer/autoload_static.php
@@ -767,6 +767,7 @@ class ComposerStaticInit53792487c5a8370acc0b06b1a864ff4c
         'OC\\Core\\Command\\Config\\System\\DeleteConfig' => __DIR__ . '/../../..' . '/core/Command/Config/System/DeleteConfig.php',
         'OC\\Core\\Command\\Config\\System\\GetConfig' => __DIR__ . '/../../..' . '/core/Command/Config/System/GetConfig.php',
         'OC\\Core\\Command\\Config\\System\\SetConfig' => __DIR__ . '/../../..' . '/core/Command/Config/System/SetConfig.php',
+        'OC\\Core\\Command\\Db\\AddMissingColumns' => __DIR__ . '/../../..' . '/core/Command/Db/AddMissingColumns.php',
         'OC\\Core\\Command\\Db\\AddMissingIndices' => __DIR__ . '/../../..' . '/core/Command/Db/AddMissingIndices.php',
         'OC\\Core\\Command\\Db\\ConvertFilecacheBigInt' => __DIR__ . '/../../..' . '/core/Command/Db/ConvertFilecacheBigInt.php',
         'OC\\Core\\Command\\Db\\ConvertMysqlToMB4' => __DIR__ . '/../../..' . '/core/Command/Db/ConvertMysqlToMB4.php',
@@ -902,6 +903,7 @@ class ComposerStaticInit53792487c5a8370acc0b06b1a864ff4c
         'OC\\DB\\MigrationException' => __DIR__ . '/../../..' . '/lib/private/DB/MigrationException.php',
         'OC\\DB\\MigrationService' => __DIR__ . '/../../..' . '/lib/private/DB/MigrationService.php',
         'OC\\DB\\Migrator' => __DIR__ . '/../../..' . '/lib/private/DB/Migrator.php',
+        'OC\\DB\\MissingColumnInformation' => __DIR__ . '/../../..' . '/lib/private/DB/MissingColumnInformation.php',
         'OC\\DB\\MissingIndexInformation' => __DIR__ . '/../../..' . '/lib/private/DB/MissingIndexInformation.php',
         'OC\\DB\\MySQLMigrator' => __DIR__ . '/../../..' . '/lib/private/DB/MySQLMigrator.php',
         'OC\\DB\\MySqlTools' => __DIR__ . '/../../..' . '/lib/private/DB/MySqlTools.php',
diff --git a/lib/private/Comments/Comment.php b/lib/private/Comments/Comment.php
index 71687c7a609..3b4a523b884 100644
--- a/lib/private/Comments/Comment.php
+++ b/lib/private/Comments/Comment.php
@@ -42,6 +42,7 @@ class Comment implements IComment {
 		'actorId'         => '',
 		'objectType'      => '',
 		'objectId'        => '',
+		'referenceId'     => null,
 		'creationDT'      => null,
 		'latestChildDT'   => null,
 	];
@@ -396,6 +397,36 @@ class Comment implements IComment {
 	}
 
 	/**
+	 * returns the reference id of the comment
+	 *
+	 * @return string|null
+	 * @since 19.0.0
+	 */
+	public function getReferenceId(): ?string {
+		return $this->data['referenceId'];
+	}
+
+	/**
+	 * sets (overwrites) the reference id of the comment
+	 *
+	 * @param string $referenceId e.g. sha256 hash sum
+	 * @return IComment
+	 * @since 19.0.0
+	 */
+	public function setReferenceId(?string $referenceId): IComment {
+		if ($referenceId === null) {
+			$this->data['referenceId'] = $referenceId;
+		} else {
+			$referenceId = trim($referenceId);
+			if ($referenceId === '') {
+				throw new \InvalidArgumentException('Non empty string expected.');
+			}
+			$this->data['referenceId'] = $referenceId;
+		}
+		return $this;
+	}
+
+	/**
 	 * sets the comment data based on an array with keys as taken from the
 	 * database.
 	 *
diff --git a/lib/private/Comments/Manager.php b/lib/private/Comments/Manager.php
index f1c72243597..d04f3f965b3 100644
--- a/lib/private/Comments/Manager.php
+++ b/lib/private/Comments/Manager.php
@@ -29,6 +29,7 @@
 namespace OC\Comments;
 
 use Doctrine\DBAL\Exception\DriverException;
+use Doctrine\DBAL\Exception\InvalidFieldNameException;
 use OCP\Comments\CommentsEvent;
 use OCP\Comments\IComment;
 use OCP\Comments\ICommentsEventHandler;
@@ -96,6 +97,7 @@ class Manager implements ICommentsManager {
 			$data['latest_child_timestamp'] = new \DateTime($data['latest_child_timestamp']);
 		}
 		$data['children_count'] = (int)$data['children_count'];
+		$data['reference_id'] = $data['reference_id'] ?? null;
 		return $data;
 	}
 
@@ -744,23 +746,46 @@ class Manager implements ICommentsManager {
 	 * @param IComment $comment
 	 * @return bool
 	 */
-	protected function insert(IComment &$comment) {
+	protected function insert(IComment $comment): bool {
+
+		try {
+			$result = $this->insertQuery($comment, true);
+		} catch (InvalidFieldNameException $e) {
+			// The reference id field was only added in Nextcloud 19.
+			// In order to not cause too long waiting times on the update,
+			// it was decided to only add it lazy, as it is also not a critical
+			// feature, but only helps to have a better experience while commenting.
+			// So in case the reference_id field is missing,
+			// we simply save the comment without that field.
+			$result = $this->insertQuery($comment, false);
+		}
+
+		return $result;
+	}
+
+	protected function insertQuery(IComment $comment, bool $tryWritingReferenceId): bool {
 		$qb = $this->dbConn->getQueryBuilder();
-		$affectedRows = $qb
-			->insert('comments')
-			->values([
-				'parent_id' => $qb->createNamedParameter($comment->getParentId()),
-				'topmost_parent_id' => $qb->createNamedParameter($comment->getTopmostParentId()),
-				'children_count' => $qb->createNamedParameter($comment->getChildrenCount()),
-				'actor_type' => $qb->createNamedParameter($comment->getActorType()),
-				'actor_id' => $qb->createNamedParameter($comment->getActorId()),
-				'message' => $qb->createNamedParameter($comment->getMessage()),
-				'verb' => $qb->createNamedParameter($comment->getVerb()),
-				'creation_timestamp' => $qb->createNamedParameter($comment->getCreationDateTime(), 'datetime'),
-				'latest_child_timestamp' => $qb->createNamedParameter($comment->getLatestChildDateTime(), 'datetime'),
-				'object_type' => $qb->createNamedParameter($comment->getObjectType()),
-				'object_id' => $qb->createNamedParameter($comment->getObjectId()),
-			])
+
+		$values = [
+			'parent_id' => $qb->createNamedParameter($comment->getParentId()),
+			'topmost_parent_id' => $qb->createNamedParameter($comment->getTopmostParentId()),
+			'children_count' => $qb->createNamedParameter($comment->getChildrenCount()),
+			'actor_type' => $qb->createNamedParameter($comment->getActorType()),
+			'actor_id' => $qb->createNamedParameter($comment->getActorId()),
+			'message' => $qb->createNamedParameter($comment->getMessage()),
+			'verb' => $qb->createNamedParameter($comment->getVerb()),
+			'creation_timestamp' => $qb->createNamedParameter($comment->getCreationDateTime(), 'datetime'),
+			'latest_child_timestamp' => $qb->createNamedParameter($comment->getLatestChildDateTime(), 'datetime'),
+			'object_type' => $qb->createNamedParameter($comment->getObjectType()),
+			'object_id' => $qb->createNamedParameter($comment->getObjectId()),
+		];
+
+		if ($tryWritingReferenceId) {
+			$values['reference_id'] = $qb->createNamedParameter($comment->getReferenceId());
+		}
+
+		$affectedRows = $qb->insert('comments')
+			->values($values)
 			->execute();
 
 		if ($affectedRows > 0) {
@@ -785,8 +810,21 @@ class Manager implements ICommentsManager {
 		$this->sendEvent(CommentsEvent::EVENT_PRE_UPDATE, $this->get($comment->getId()));
 		$this->uncache($comment->getId());
 
+		try {
+			$result = $this->updateQuery($comment, true);
+		} catch (InvalidFieldNameException $e) {
+			// See function insert() for explanation
+			$result = $this->updateQuery($comment, false);
+		}
+
+		$this->sendEvent(CommentsEvent::EVENT_UPDATE, $comment);
+
+		return $result;
+	}
+
+	protected function updateQuery(IComment $comment, bool $tryWritingReferenceId): bool {
 		$qb = $this->dbConn->getQueryBuilder();
-		$affectedRows = $qb
+		$qb
 			->update('comments')
 			->set('parent_id', $qb->createNamedParameter($comment->getParentId()))
 			->set('topmost_parent_id', $qb->createNamedParameter($comment->getTopmostParentId()))
@@ -798,17 +836,19 @@ class Manager implements ICommentsManager {
 			->set('creation_timestamp', $qb->createNamedParameter($comment->getCreationDateTime(), 'datetime'))
 			->set('latest_child_timestamp', $qb->createNamedParameter($comment->getLatestChildDateTime(), 'datetime'))
 			->set('object_type', $qb->createNamedParameter($comment->getObjectType()))
-			->set('object_id', $qb->createNamedParameter($comment->getObjectId()))
-			->where($qb->expr()->eq('id', $qb->createParameter('id')))
-			->setParameter('id', $comment->getId())
+			->set('object_id', $qb->createNamedParameter($comment->getObjectId()));
+
+		if ($tryWritingReferenceId) {
+			$qb->set('reference_id', $qb->createNamedParameter($comment->getReferenceId()));
+		}
+
+		$affectedRows = $qb->where($qb->expr()->eq('id', $qb->createNamedParameter($comment->getId())))
 			->execute();
 
 		if ($affectedRows === 0) {
 			throw new NotFoundException('Comment to update does ceased to exist');
 		}
 
-		$this->sendEvent(CommentsEvent::EVENT_UPDATE, $comment);
-
 		return $affectedRows > 0;
 	}
 
diff --git a/lib/private/DB/MissingColumnInformation.php b/lib/private/DB/MissingColumnInformation.php
new file mode 100644
index 00000000000..bcf585848fd
--- /dev/null
+++ b/lib/private/DB/MissingColumnInformation.php
@@ -0,0 +1,43 @@
+<?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\DB;
+
+class MissingColumnInformation {
+
+	private $listOfMissingColumns = [];
+
+	public function addHintForMissingColumn(string $tableName, string $columnName): void {
+		$this->listOfMissingColumns[] = [
+			'tableName' => $tableName,
+			'columnName' => $columnName,
+		];
+	}
+
+	public function getListOfMissingColumns(): array {
+		return $this->listOfMissingColumns;
+	}
+}
diff --git a/lib/public/Comments/IComment.php b/lib/public/Comments/IComment.php
index aac68a4036b..b98a015a30e 100644
--- a/lib/public/Comments/IComment.php
+++ b/lib/public/Comments/IComment.php
@@ -263,4 +263,21 @@ interface IComment {
 	 */
 	public function setObject($objectType, $objectId);
 
+	/**
+	 * returns the reference id of the comment
+	 *
+	 * @return string|null
+	 * @since 19.0.0
+	 */
+	public function getReferenceId(): ?string;
+
+	/**
+	 * sets (overwrites) the reference id of the comment
+	 *
+	 * @param string|null $referenceId e.g. sha256 hash sum
+	 * @return IComment
+	 * @since 19.0.0
+	 */
+	public function setReferenceId(?string $referenceId): IComment;
+
 }
diff --git a/lib/public/IDBConnection.php b/lib/public/IDBConnection.php
index 0cc29d3be46..a7aa9d448f1 100644
--- a/lib/public/IDBConnection.php
+++ b/lib/public/IDBConnection.php
@@ -51,6 +51,8 @@ interface IDBConnection {
 
 	const ADD_MISSING_INDEXES_EVENT = self::class . '::ADD_MISSING_INDEXES';
 	const CHECK_MISSING_INDEXES_EVENT = self::class . '::CHECK_MISSING_INDEXES';
+	const ADD_MISSING_COLUMNS_EVENT = self::class . '::ADD_MISSING_COLUMNS';
+	const CHECK_MISSING_COLUMNS_EVENT = self::class . '::CHECK_MISSING_COLUMNS';
 
 	/**
 	 * Gets the QueryBuilder for the connection.