Successful cross-mapping launch | The Fabric Project | Page 1

near dagger Feb 9, 2026, 2:22 PM

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pingudance I've finally achieved a successful mod launch on 26.1 Snapshot 6 after compiling the mod on 1.21.11 thinkbro
Notice, 26.1 is already unobfuscated, while 1.21.11 uses obfuscation and usually compiles in intermediary namespace.

Done using ✨ Version't versiont

On the screenshot you can see a GUI implemented by extending the BookViewScreen class, which normally, due to mapping mismatch, would lead to a ClassDefNotFound exception.

-# "Version't" isn't yet production-ready, it's not well documented, tiresome to use and a bit cursed concern

tame jetty Feb 9, 2026, 2:27 PM

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neat, is this similar to the backcompat mappings that @modern valley has been working on?

near dagger Feb 9, 2026, 2:28 PM

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Nope, this uses Java Reflection and runtime Byte Code generation under the hood to wrap Minecraft classes

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Technically the mod doesn't need any mappings at all during compilation

tame jetty Feb 9, 2026, 2:28 PM

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fascinating... so you really do just produce one mod jar for every version?

near dagger Feb 9, 2026, 2:28 PM

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Since you provide your own mappings

near dagger Feb 9, 2026, 2:29 PM

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tame jetty fascinating... so you really do just produce one mod jar for every version?

Yes, right now supports all versions from 1.17 to 1.21.11, all in a single jar 😇

tame jetty Feb 9, 2026, 2:29 PM

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that is REALLY COOL

near dagger Feb 9, 2026, 2:29 PM

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Including 26.1 as well, but I am not yet fully migrating, since snapshot stuff might change

tame jetty Feb 9, 2026, 2:30 PM

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how do you handle version specific resource loading?

near dagger Feb 9, 2026, 2:31 PM

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A facade-like pattern which delegates to version specific implementation

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tame jetty Feb 9, 2026, 2:32 PM

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wow that is really excellent

near dagger Feb 9, 2026, 2:32 PM

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This is used in the init logic of my GUI

tame jetty Feb 9, 2026, 2:32 PM

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i'll definitely check it out once you publish it

near dagger Feb 9, 2026, 2:32 PM

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A bit tiresome to write and then also check every single version when you create some new feature

near dagger Feb 9, 2026, 2:32 PM

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near dagger A bit tiresome to write and then also check every single version when you create...

But personally I don't mind the effort

tame jetty Feb 9, 2026, 2:33 PM

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near dagger A bit tiresome to write and then also check every single version when you create...

right but not materially more than stonecutter already, yeah?

near dagger Feb 9, 2026, 2:33 PM

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Well, yeah, kinda

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But you also have to make sure, that you save the correct mappings

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This is my mapping format

tame jetty Feb 9, 2026, 2:34 PM

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ohh a custom mapping format

near dagger Feb 9, 2026, 2:34 PM

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it's cursed as fk

modern valley Feb 9, 2026, 2:35 PM

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I've seen this (your thing) before yeah, it's cursed as fuck

near dagger Feb 9, 2026, 2:35 PM

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For any Minecraft class I use I basically create a mapping that exposes the methods that I need, then I generate the code for it and instead of e.g. "import net.minecraft.client.Minecraft" I go with "import dev.gxlg.versiont.get.net.minecraft.client.Minecraft"

tame jetty Feb 9, 2026, 2:36 PM

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huh

near dagger Feb 9, 2026, 2:36 PM

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modern valley I've seen this (your thing) before yeah, it's cursed as fuck

I've changed reflection to use handles 😇

near dagger Feb 9, 2026, 2:37 PM

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tame jetty huh

Well, since when it compiles in intermediary environment, it's gonna be like "net.minecraft.class_123"

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And 26.1 has no idea what that is

tame jetty Feb 9, 2026, 2:37 PM

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near dagger For any Minecraft class I use I basically create a mapping that exposes the meth...

so it uses a custom classloader i guess?

near dagger Feb 9, 2026, 2:37 PM

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So I have a generated class that wraps around that class

near dagger Feb 9, 2026, 2:37 PM

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tame jetty so it uses a custom classloader i guess?

Uh, that would've been smart, ig, but no, I just use reflection

tame jetty Feb 9, 2026, 2:38 PM

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lol

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maybe worth looking into

near dagger Feb 9, 2026, 2:38 PM

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tame jetty Feb 9, 2026, 2:39 PM

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i see

modern valley Feb 9, 2026, 2:39 PM

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near dagger I've changed reflection to use handles 😇

yayyy

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so it's much faster now?

near dagger Feb 9, 2026, 2:39 PM

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Yess

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Well

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I didn't really feel a big difference honestly

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Cuz it wasn't slow before

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But in theory it is faster

modern valley Feb 9, 2026, 2:40 PM

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could you make an example mod using this?

near dagger Feb 9, 2026, 2:40 PM

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And it's thread safe now

near dagger Feb 9, 2026, 2:41 PM

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modern valley could you make an example mod using this?

Sure, I'll do just a "com.example" thing with a client-side command, that runs both on 1.21.11 and 26.1. or do you want something specific?

modern valley Feb 9, 2026, 2:43 PM

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uhh, maybe like, not that cuz that uses fapi

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do like uhhh

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hmmm

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adding a new screen which in text shows the items in your inventory

near dagger Feb 9, 2026, 2:53 PM

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Alright, let me cook. Currently eating, gonna do in like 1 h

near dagger Feb 9, 2026, 5:51 PM

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Sorry, gonna take a bit longer, realized that I could improve runtime class creation, because right now it is painfully slow

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Thx copilot

near dagger Feb 9, 2026, 6:39 PM

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@modern valley
Version't Library (local build, differs from the current published one)
Template Mod
Template Mod Sources (if you want to check, well, the source code)

📎 versiont-library-0.0.3.jar 📎 template-mod-1.0.0.jar 📎 template-mod-1.0.0-sources.jar

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Runs in 1.21.11 and 26.1

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Haven't checked other versions

modern valley Feb 9, 2026, 6:40 PM

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upload it to github ?

near dagger Feb 9, 2026, 6:40 PM

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Uh, nah, it's just ugly quick template mod

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Version't Library and the Toolchain are both on GitHub, I am working on imrpovements locally right now

weak sundial Feb 10, 2026, 9:12 AM

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@near dagger This looks a lot like the framework I'm working on 👀

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test-mod-fabric/TestMod.java
test-minecraft-facades

near dagger Feb 10, 2026, 5:19 PM

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weak sundial <@557260090621558805> This looks a lot like the framework I'm working on 👀

Oh, looks interesting

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Does it work regardless of mappings?

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Ah, as I see, it indeed does

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This is peak

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Yours looks better and easier to use when it comes to usage 😭

weak sundial Feb 10, 2026, 5:34 PM

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near dagger Does it work regardless of mappings?

It's planned yes haha

weak sundial Feb 10, 2026, 5:34 PM

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near dagger Yours looks better and easier to use when it comes to usage 😭

It's also very much hell in terms of code, I've had the idea for years and finally gathered enough motivation to go with the "write code until it runs" mentality to avoid overengineering stuff

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Also sorry, didn't mean to hijack your thread 😓

#Successful cross-mapping launch