Added locks to tag and domain creation during short URL creation

module/Core/src/Repository/TagRepository.php

@@ -4,6 +4,7 @@ declare(strict_types=1);
 
 namespace Shlinkio\Shlink\Core\Repository;
 
+use Doctrine\DBAL\LockMode;
 use Happyr\DoctrineSpecification\Repository\EntitySpecificationRepository;
 use Happyr\DoctrineSpecification\Spec;
 use Shlinkio\Shlink\Core\Entity\Tag;
@@ -62,4 +63,16 @@ class TagRepository extends EntitySpecificationRepository implements TagReposito
 
         return $result > 0;
     }
+
+    public function findOneByNameWithLock(string $name): ?Tag
+    {
+        $qb = $this->createQueryBuilder('t');
+        $qb->where($qb->expr()->eq('t.name', ':name'))
+           ->setParameter('name', $name)
+           ->setMaxResults(1);
+
+        $query = $qb->getQuery()->setLockMode(LockMode::PESSIMISTIC_WRITE);
+
+        return $query->getOneOrNullResult();
+    }
 }

module/Core/src/Repository/TagRepositoryInterface.php

@@ -6,6 +6,7 @@ namespace Shlinkio\Shlink\Core\Repository;
 
 use Doctrine\Persistence\ObjectRepository;
 use Happyr\DoctrineSpecification\Repository\EntitySpecificationRepositoryInterface;
+use Shlinkio\Shlink\Core\Entity\Tag;
 use Shlinkio\Shlink\Core\Tag\Model\TagInfo;
 use Shlinkio\Shlink\Rest\Entity\ApiKey;
 
@@ -19,4 +20,6 @@ interface TagRepositoryInterface extends ObjectRepository, EntitySpecificationRe
     public function findTagsWithInfo(?ApiKey $apiKey = null): array;
 
     public function tagExists(string $tag, ?ApiKey $apiKey = null): bool;
+
+    public function findOneByNameWithLock(string $name): ?Tag;
 }