When Path::canChmod($file) returns false method throws an exception as if deletion is not possible but some servers have such setup that chmod is not but file deletion is possible.

Because of this I got errors when trying to update extensions but after commenting out this and line below that is trying to chmod file to 0777 update was success.

In my opinion unlink($file) should be executed even if chmod is not possible and this is a bug that can cause issues for some users.