TypeHash invalid with a custom online subsystem

Since version 4.20, the client/server projects are returning

LogNet: Warning: Error with encoded type hash

I have a custom Online subsystem

class ONLINESUBSYSTEMKADEO_API FOnlineSubsystemKadeo :
	public FOnlineSubsystemNull

The problem is that we cannot provide a hash type with the subsystem “Kadeo”

In NetSerialize function

bool FUniqueNetIdRepl::NetSerialize(FArchive& Ar, UPackageMap* Map, bool& bOutSuccess)
{

…
…
					uint8 TypeHash = GetTypeHashFromEncoding(EncodingFlags);
					if (TypeHash == 0)
					{
						// If no type was encoded, assume default
						TypeHash = UOnlineEngineInterface::Get()->GetReplicationHashForSubsystem(UOnlineEngineInterface::Get()->GetDefaultOnlineSubsystemName());
					}
….

With custom online subsystem, it return 0 since the subsystem cannot be registered in FOnlineSubsystemUtils in the private function CreateNameHashes()

	void CreateNameHashes()
	{
		int32 HashId = 1;
#define CREATE_HASH(MacroName) \
{ \
 uint8 Hash = static_cast<uint8>(HashId); \
 SubsystemNameToHash.Add(MacroName, Hash); \
 HashToSubsystemName.Add(Hash, MacroName); \
 HashId++; \
}
		CREATE_HASH(NULL_SUBSYSTEM); 
		CREATE_HASH(MCP_SUBSYSTEM);
		CREATE_HASH(STEAM_SUBSYSTEM);
		CREATE_HASH(PS4_SUBSYSTEM);
		CREATE_HASH(LIVE_SUBSYSTEM);
		CREATE_HASH(GOOGLE_SUBSYSTEM);
		CREATE_HASH(GOOGLEPLAY_SUBSYSTEM);
		CREATE_HASH(FACEBOOK_SUBSYSTEM);
		CREATE_HASH(IOS_SUBSYSTEM);
		CREATE_HASH(TENCENT_SUBSYSTEM);
		CREATE_HASH(SWITCH_SUBSYSTEM);
		CREATE_HASH(AMAZON_SUBSYSTEM);
		CREATE_HASH(GAMECIRCLE_SUBSYSTEM);
		CREATE_HASH(THUNDERHEAD_SUBSYSTEM); 
		CREATE_HASH(WECHAT_SUBSYSTEM); 
		CREATE_HASH(TWITCH_SUBSYSTEM); 
		CREATE_HASH(OCULUS_SUBSYSTEM); 
		CREATE_HASH(QUAIL_SUBSYSTEM);
		// Shouldn't need these as they are mocking interfaces for existing platforms
		CREATE_HASH(PS4SERVER_SUBSYSTEM);
		CREATE_HASH(LIVESERVER_SUBSYSTEM);

#undef CREATE_HASH


		ensure(SubsystemNameToHash.Num() == (HashId - 1));
		ensure(HashToSubsystemName.Num() == (HashId - 1));
	}

How can I register my own online subsystem ?

I’m having the same issue. This is a common sense “feature”.

By hard-coding this, the programmer responsible essentially created a circular dependency between the subsystem utilities and the subsystems themselves. 0/10 wouldn’t even consider hiring them.

Absolutely terrible work by whoever did this at Epic. Really hope this will be fixed in 4.21, or better yet, the next patch for 4.20.

Noticed this as well. Has there been any update?

For the love of pete please fix this ASAP…

Has anyone filled out a Bug Report about this yet?

I did not filled any bug reports for this.
I stay in 4.19.2 version :wink:

Bump.

Pitchfork thread here:
https://forums.unrealengine.com/unreal-engine/feedback-for-epic/1518161-seriously-damaging-change-to-online-subsystems-in-4-20

Apologies for breaking your custom online subsystem implementations.   Two features that improved UniqueId overall came together to break the code in question.

1) UniqueId compression - up until now, in the interest of simplicity, we were simplify passing a string across the network.  This was grossly inefficient, but for small player counts it wasn’t on our radar.   For Epic’s unique id scheme, a guid, it was 43 bytes to replicate.   We found that we could pack this into nibbles and save a ton of space.  The code now serializes at 18 bytes, which is significant savings in FNBR where we replicate 100 user ids to everyone (10k replications x 43 bytes). Additionally for cross play we replicate other platform unique ids (10k x 64bit number in string format).  These weren’t as big a savings, but since they were straight up integers, we could pack them the same way.

2) UniqueId type - again for crossplay, we needed to better understand what type of UniqueId we were dealing with without having to cross reference other systems.   Replicating the type without losing savings from 1 is the reason for the “hash/index” value that is causing you trouble.  5 bits of the packet were used to have room for 32 online subsystems.  Of course this means we need to know ahead of time all the values.   This is clearly not conducive to custom implementations.

We are going to fix this.    We will use one of the bits to signify a custom Online Subsystem, and pack the name of your system into the packet.  We thought about some way to deterministically register all known online subsystems, but this won’t work given that not all will register in all scenarios (not all platforms register all subsystems).   The simplest thing to do is sacrifice a little bit of the compression savings for simplicity and convenience.

We are looking to get an implementation in ASAP and have it available with the one of the next 4.20 hotfix releases.

Apologies for the delay in a response, we do not often get a lot of visibility into specific forum issues.   I hope this addresses the concerns, the online team does care about the pains of other developers.

Thank you for taking the time to write the detailed explanation and looking into fixing this! Now it makes sense.

thank you.

Any updates with this? Our project uses Uworks, and we are getting the same TypeHash error on 4.20.3. Is there anything that needs to be done to get custom OSS to work on 4.20.3?

I’m very curious about this too. I’m building a new prototype and my list of TODOs that are precursors to steam integration is shrinking rapidly.

Has anyone actually got the fix from 4.20.3 working? I’m on 4.21 and I can’t get any external subsystem to work at all. Same stupid hash issue.

For anyone reading this, I found the problem and posted it in the thread and I’ll paste the text below as well.

Found the fix for the hash issue. Instead of adding a hash, given the “fix” implemented by Epic in 4.20.3, we now need to override the following function in FUniqueNetIdUWorks, inherited from FUniqueNetId:

virtual FName GetType() const override
{
    return TEXT("UWorks");
}

It wasn’t even a pure virtual method. There wasn’t any indication whatsoever to make me check this. I found this mostly by mistake.

So I’ve done what vlad.serbanescu11 has suggested and when the server is getting the hash for the subsystem. It’s still only checking the official 20 subsystems.

note: I am not deriving from any of the official subsystems, but mine is basically just a copy of the steam subsystem. Also I created my own OnlineSusbytemNames.h called OnlineSubsystemCustomNames.h which includes OnlineSusbytemNames.h and defines my custom OSS. So I’ve already done the GetType() thing, it seems like I need to hash my OSS name and add it to SubsystemNameToHash but I have no idea how to do that. Has anybody solved this?

I just realized I’m on 4.20.2 so maybe that’s the problem

Switch to version 4.21.2 and it finally works.