fix: populate cache when creating user

Signed-off-by: Robin Appelman <robin@icewind.nl>

Author: icewind1991

lib/UserBackend.php

@@ -38,6 +38,7 @@ class UserBackend extends ABackend implements
 	IGetRealUIDBackend,
 	IPasswordHashBackend {
 
+	/** @var CappedMemoryCache<array{'uid': string, 'displayname': ?string}> */
 	private CappedMemoryCache $cache;
 
 	private bool $allowListing = true;
@@ -73,8 +74,9 @@ public function createUser(string $uid, string $password): bool {
 
 			$result = $qb->executeStatement();
 
-			// Clear cache
-			unset($this->cache[$uid]);
+			$this->cache[$uid] = [];
+			$this->cache[$uid]['uid'] = $uid;
+			$this->cache[$uid]['displayname'] = null;
 
 			return (bool)$result;
 		}
@@ -109,7 +111,11 @@ public function setInitialEmail(string $uid, string $email): bool {
 		$query->update('guests_users')
 			->set('email', $query->createNamedParameter($email))
 			->where($query->expr()->eq('uid_lower', $query->createNamedParameter(mb_strtolower($uid))));
-		return (bool)$query->executeStatement();
+		$result = (bool)$query->executeStatement();
+		if ($result && isset($this->cache[$uid])) {
+			$this->cache[$email] = $this->cache[$uid];
+		}
+		return $result;
 	}
 
 	/**