When I first made VolumeVerifier, I figured that the distinction
between an unsigned ticket and an unsigned TMD was a technical
detail that users would have no reason to care about. However,
while this might be true for discs, it isn't equally true for
WADs, due to the widespread practice of fakesigning tickets to
set the console ID to 0. This practice does not require
fakesigning the TMD (though apparently people do it anyway,
at least sometimes...), and the presence of a correctly signed
TMD is a useful indicator that the contents have not been
tampered with, even if the ticket isn't correctly signed.
Instead of comparing the game ID, revision, disc number and name,
we can compare a hash of important parts of the disc including
all the aforementioned data but also additional data such as the
FST. The primary reason why I'm making this change is to let us
catch more desyncs before they happen, but this should also fix
https://bugs.dolphin-emu.org/issues/12115. As a bonus, the UI can
now distinguish the case where a client doesn't have the game at
all from the case where a client has the wrong version of the game.
It is my opinion that nobody should use NKit disc images without
being aware of the drawbacks of them. Since it seems like almost
nobody who is using NKit disc images knows what NKit is (hmm, now
how could that have happened...?), I am adding a warning to Dolphin
so that you can't run NKit disc images without finding out about the
drawbacks. In case someone really does want to use NKit disc images,
the warning has a "Don't show this again" option. Unfortunately, I
can't retroactively add the warning where it's most needed:
in Dolphin 5.0, which does not support Wii NKit disc images.
This could cause read errors if chunks were laid out a certain
way in the file and the whole chunk wasn't being read at once.
Should fix https://bugs.dolphin-emu.org/issues/12184.
PURGE isn't especially useful, while requiring some annoying
special handling in the file format. If you want no compression,
use NONE. If you want fast compression, use Zstandard.