[1.21.3] Add condition to validate feature flags enabled state

[ApexModder]

Modders who maintain multi-jar mods, that being mods whose feature set is split across multiple jars, may want a single flag in their common jar which toggles features across all of their mod jars. Due to the nature of how feature packs work and are enabled, this is not possible.

While you can have multiple packs which all enable the same flag, they will all display as individual selections in the "experiments" screen, when the intention is to have 1 toggle for all these packs.

To work around that, modders can make use of the newly added condition in this PR, which takes in a set of feature flags and whether to validate for them being enabled or disabled to conditionally load their desired elements without needing to be in the same feature pack.

[neoforged-pr-publishing]

• Publish PR to GitHub Packages

Last commit published: 6c6e026a039be0f4ec5dd29f32d84936f85858f7.

PR Publishing

The artifacts published by this PR:

• 📦 net.neoforged:testframework:21.3.53-beta-pr-1712-pr-flag-condition
• 📦 net.neoforged:neoforge:21.3.53-beta-pr-1712-pr-flag-condition

Repository Declaration

In order to use the artifacts published by the PR, add the following repository to your buildscript:

repositories {
    maven {
        name 'Maven for PR #1712' // https://github.com/neoforged/NeoForge/pull/1712
        url 'https://prmaven.neoforged.net/NeoForge/pr1712'
        content {
            includeModule('net.neoforged', 'testframework')
            includeModule('net.neoforged', 'neoforge')
        }
    }
}

MDK installation

In order to setup a MDK using the latest PR version, run the following commands in a terminal.
The script works on both *nix and Windows as long as you have the JDK bin folder on the path.
The script will clone the MDK in a folder named NeoForge-pr1712.
On Powershell you will need to remove the -L flag from the curl invocation.

mkdir NeoForge-pr1712
cd NeoForge-pr1712
curl -L https://prmaven.neoforged.net/NeoForge/pr1712/net/neoforged/neoforge/21.3.53-beta-pr-1712-pr-flag-condition/mdk-pr1712.zip -o mdk.zip
jar xf mdk.zip
rm mdk.zip || del mdk.zip

To test a production environment, you can download the installer from here.

[neoforged-releases]

🚀 This PR has been released as NeoForge version 21.3.48-beta.