From 5de021cb9aed754191072ffd9b81cac39c5b8f86 Mon Sep 17 00:00:00 2001
From: Lucas Azevedo <lhs_azevedo@hotmail.com>
Date: Fri, 1 Sep 2023 14:05:15 -0300
Subject: [PATCH 1/2] fix(mimetype): Remove unnecessary transaction when
 storing a mime type

Fixes #40064.

This could be fixed by adding a rollback and starting a new transaction
before the SELECT query, but in this case that would have the same
effect as not using one.
See https://dev.mysql.com/doc/refman/8.0/en/innodb-autocommit-commit-rollback.html
and https://www.postgresql.org/docs/7.1/sql-begin.html#R1-SQL-BEGIN-1

Signed-off-by: Lucas Azevedo <lhs_azevedo@hotmail.com>
---
 lib/private/Files/Type/Loader.php | 48 ++++++++++++++-----------------
 1 file changed, 22 insertions(+), 26 deletions(-)

diff --git a/lib/private/Files/Type/Loader.php b/lib/private/Files/Type/Loader.php
index 20c298f21b3d5..7ca1b677fb591 100644
--- a/lib/private/Files/Type/Loader.php
+++ b/lib/private/Files/Type/Loader.php
@@ -116,35 +116,31 @@ public function reset() {
 	 * @return int inserted ID
 	 */
 	protected function store($mimetype) {
-		$mimetypeId = $this->atomic(function () use ($mimetype) {
-			try {
-				$insert = $this->dbConnection->getQueryBuilder();
-				$insert->insert('mimetypes')
-					->values([
-						'mimetype' => $insert->createNamedParameter($mimetype)
-					])
-					->executeStatement();
-				return $insert->getLastInsertId();
-			} catch (DbalException $e) {
-				if ($e->getReason() !== DBException::REASON_UNIQUE_CONSTRAINT_VIOLATION) {
-					throw $e;
-				}
-				$qb = $this->dbConnection->getQueryBuilder();
-				$qb->select('id')
-					->from('mimetypes')
-					->where($qb->expr()->eq('mimetype', $qb->createNamedParameter($mimetype)));
-				$result = $qb->executeQuery();
-				$id = $result->fetchOne();
-				$result->closeCursor();
-				if ($id !== false) {
-					return (int) $id;
-				}
+		try {
+			$insert = $this->dbConnection->getQueryBuilder();
+			$insert->insert('mimetypes')
+				->values([
+					'mimetype' => $insert->createNamedParameter($mimetype)
+				])
+				->executeStatement();
+			$mimetypeId = $insert->getLastInsertId();
+		} catch (DbalException $e) {
+			if ($e->getReason() !== DBException::REASON_UNIQUE_CONSTRAINT_VIOLATION) {
+				throw $e;
+			}
+
+			$qb = $this->dbConnection->getQueryBuilder();
+			$qb->select('id')
+				->from('mimetypes')
+				->where($qb->expr()->eq('mimetype', $qb->createNamedParameter($mimetype)));
+			$result = $qb->executeQuery();
+			$id = $result->fetchOne();
+			$result->closeCursor();
+			if ($id === false) {
 				throw new \Exception("Database threw an unique constraint on inserting a new mimetype, but couldn't return the ID for this very mimetype");
 			}
-		}, $this->dbConnection);
 
-		if (!$mimetypeId) {
-			throw new \Exception("Failed to get mimetype id for $mimetype after trying to store it");
+			$mimetypeId = (int) $id;
 		}
 
 		$this->mimetypes[$mimetypeId] = $mimetype;

From c587f684bd18b2572249d46cd9ffe45e43f9c98f Mon Sep 17 00:00:00 2001
From: Lucas Azevedo <lhs_azevedo@hotmail.com>
Date: Mon, 4 Sep 2023 08:02:35 -0300
Subject: [PATCH 2/2] Wrap mimetype insert and getLastInsertId in a transaction

Signed-off-by: Lucas Azevedo <lhs_azevedo@hotmail.com>
---
 lib/private/Files/Type/Loader.php | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/lib/private/Files/Type/Loader.php b/lib/private/Files/Type/Loader.php
index 7ca1b677fb591..7032e6193850f 100644
--- a/lib/private/Files/Type/Loader.php
+++ b/lib/private/Files/Type/Loader.php
@@ -117,13 +117,15 @@ public function reset() {
 	 */
 	protected function store($mimetype) {
 		try {
-			$insert = $this->dbConnection->getQueryBuilder();
-			$insert->insert('mimetypes')
-				->values([
-					'mimetype' => $insert->createNamedParameter($mimetype)
-				])
-				->executeStatement();
-			$mimetypeId = $insert->getLastInsertId();
+			$mimetypeId = $this->atomic(function () use ($mimetype) {
+				$insert = $this->dbConnection->getQueryBuilder();
+				$insert->insert('mimetypes')
+					->values([
+						'mimetype' => $insert->createNamedParameter($mimetype)
+					])
+					->executeStatement();
+				return $insert->getLastInsertId();
+			}, $this->dbConnection);
 		} catch (DbalException $e) {
 			if ($e->getReason() !== DBException::REASON_UNIQUE_CONSTRAINT_VIOLATION) {
 				throw $e;