fix: prevent invalid return type

Signed-off-by: Christoph Wurst <[email protected]>

Author: ChristophWurst

lib/IMAP/ImapMessageFetcher.php

@@ -504,7 +504,12 @@ private function decodeSubject(Horde_Imap_Client_Data_Envelope $envelope): strin
 		if ($utf8 !== false) {
 			return $utf8;
 		}
-		return iconv('UTF-8', 'UTF-8//IGNORE', $subject);
+		$utf8Ignored = iconv('UTF-8', 'UTF-8//IGNORE', $subject);
+		if ($utf8Ignored === false) {
+			// Give up
+			return $subject;
+		}
+		return $utf8Ignored;
 	}
 
 	private function parseHeaders(Horde_Imap_Client_Data_Fetch $fetch): void {

lib/Service/Classification/PersistenceService.php

@@ -205,7 +205,15 @@ private function getCached(string $id): ?array {
 		}
 
 		$serializedData = json_decode($json);
-		return array_map(base64_decode(...), $serializedData);
+		$decodedData = array_map(base64_decode(...), $serializedData);
+		foreach ($decodedData as $decoded) {
+			if ($decoded === false) {
+				// Decoding failed, abort
+				return null;
+			}
+		}
+		/** @var string[] $decodedData */
+		return $decodedData;
 	}
 
 	/**