Versioning and server compatibility

[Jay Avery]

I'm trying to figure out how to name and define versions for my mod. I know that any version will only be compatible with a single minecraft/forge version - which will be defined in @Mod.acceptedMinecraftVersions, in "mcversion" in the mcmod.info, and in the minecraft version section in build.gradle. (Am I on the right lines so far?)

 

With other things as their default, the mod only allows a client to connect to a server which has the exact same mod version. So, say a 1.0.0.0 client can't connect to a 1.0.1.0 server. I'd like to allow clients to connect as long as their major version matches - so 1.0.1.0 should be able to connect to 1.0.0.0, but 2.0.0.0 shouldn't. I know there's @Mod.acceptableRemoteVersions. But I just tested that by setting it to the exact current version of the mod (i.e., I expected the result of this to be the same as if I hadn't changed this from the default at all), and ended up being able to connect to a server that wasn't even forge, let alone had my mod installed. Do I need to change a setting elsewhere, like in build.gradle or mcmod.info too? Have I misunderstood what acceptableRemoteVersions is supposed to do?

 

I'm just confused because there are settings and metadata in various different places and they seem to all be important in similar but distinct ways and I can't figure it all out.  It would be great if there was a summary somewhere about what the different bits do and how they relate, if anyone can recommend such a source? I've looked at the forge docs and stuff, but information about the different aspects is quite disjointed and separate and that's what I'm having trouble with.

[Choonster]

22 minutes ago, Jay Avery said:

I'm trying to figure out how to name and define versions for my mod. I know that any version will only be compatible with a single minecraft/forge version - which will be defined in @Mod.acceptedMinecraftVersions, in "mcversion" in the mcmod.info, and in the minecraft version section in build.gradle. (Am I on the right lines so far?)

 

That's correct.

 

22 minutes ago, Jay Avery said:

With other things as their default, the mod only allows a client to connect to a server which has the exact same mod version. So, say a 1.0.0.0 client can't connect to a 1.0.1.0 server. I'd like to allow clients to connect as long as their major version matches - so 1.0.1.0 should be able to connect to 1.0.0.0, but 2.0.0.0 shouldn't. I know there's @Mod.acceptableRemoteVersions. But I just tested that by setting it to the exact current version of the mod (i.e., I expected the result of this to be the same as if I hadn't changed this from the default at all), and ended up being able to connect to a server that wasn't even forge, let alone had my mod installed. Do I need to change a setting elsewhere, like in build.gradle or mcmod.info too? Have I misunderstood what acceptableRemoteVersions is supposed to do?

 

@Mod#acceptableRemoteVerions expects a version range, not just a single version. It's parsed using VersionRange.createFromVersionSpec, which has a doc comment explaining the format.

[Jay Avery]

From the comment, it looks like a single version string should be interpreted as a valid version range - shouldn't it? And I don't understand how, even if I wrote the version range in the wrong format, it ends up letting me connect to a non-forge server. I would expect it to just not allow connecting to any server if it doesn't understand the version range I've given?

[Jay Avery]

Do I just have the wrong idea about how forge server compatibility works? Is it always possible to connect to a vanilla server from a forge client?

[Choonster]

5 hours ago, Jay Avery said:

From the comment, it looks like a single version string should be interpreted as a valid version range - shouldn't it?

 

You're right, I missed that.

 

 

5 hours ago, Jay Avery said:

And I don't understand how, even if I wrote the version range in the wrong format, it ends up letting me connect to a non-forge server. I would expect it to just not allow connecting to any server if it doesn't understand the version range I've given?

 

Looking into the code further, it appears that using a single version rather than one or more version ranges creates a VersionRange with a single Restriction (Restriction.EVERYTHING) that matches everything and completely ignores the version you passed it.

 

In addition to this, NetworkModHolder.DefaultNetworkChecker (the default implementation used to check if the remote mod list is compatible with the local mods) allows the client to connect to a server without the mod installed.

 

I'm not sure of the reason behind either of these.

 

You can work around the latter by providing your own NetworkChecker, just annotate a method with @NetworkCheckHandler. See the doc comment for the required signature.

[Jay Avery]

Thanks for the tip! I've implemented my own NetworkChecker, and then found that... it still ignores the version compatibility when connecting to vanilla servers. I tracked it down to FMLHandshakeClientState.HELLO, where it shortcuts all the checks and immediately returns DONE if it doesn't get an FML message from the server. So I don't even get a chance to intervene using my own NetworkChecker. So I guess this means that any forge client will always be able to connect to a vanilla server, and I just have to trust users not to be silly enough to do that? It seems like a strange arrangement..

Edited June 16, 2017 by Jay Avery