Fix tar type detection for hidden archives

Signed-off-by: Yuhang Cao <caoyuhang@fwerkor.com>

Author: fwerkor

lib/private/Archive/TAR.php

@@ -40,7 +40,7 @@ public function __construct(
 	 * try to detect the type of tar compression
 	 */
 	public static function getTarType(string $file): int {
-		if (strpos($file, '.')) {
+		if (strrpos($file, '.') !== false) {
 			$extension = substr($file, strrpos($file, '.'));
 			switch ($extension) {
 				case '.gz':

tests/lib/Archive/TARTest.php

@@ -13,6 +13,12 @@
 use OCP\Server;
 
 class TARTest extends TestBase {
+	public function testGetTarTypeWithHiddenArchiveNames(): void {
+		$this->assertSame(TAR::GZIP, TAR::getTarType('.tar.gz'));
+		$this->assertSame(TAR::GZIP, TAR::getTarType('.tgz'));
+		$this->assertSame(TAR::BZIP, TAR::getTarType('.tar.bz2'));
+	}
+
 	#[\Override]
 	protected function getExisting() {
 		$dir = \OC::$SERVERROOT . '/tests/data';