fix: Isolate mixins in alternative source sets

src/main/kotlin/Compat.kt

@@ -0,0 +1,11 @@
+package moe.nea.firmament
+
+import moe.nea.firmament.util.compatloader.CompatMeta
+import moe.nea.firmament.util.compatloader.ICompatMeta
+
+@CompatMeta
+object Compat : ICompatMeta {
+	override fun shouldLoad(): Boolean {
+		return true
+	}
+}

src/main/kotlin/features/FeatureManager.kt

@@ -31,6 +31,7 @@ import moe.nea.firmament.features.mining.PickaxeAbility
 import moe.nea.firmament.features.mining.PristineProfitTracker
 import moe.nea.firmament.features.world.FairySouls
 import moe.nea.firmament.features.world.Waypoints
+import moe.nea.firmament.util.compatloader.ICompatMeta
 import moe.nea.firmament.util.data.DataHolder
 
 object FeatureManager : DataHolder<FeatureManager.Config>(serializer(), "features", ::Config) {
@@ -83,17 +84,18 @@ object FeatureManager : DataHolder<FeatureManager.Config>(serializer(), "feature
 
 	fun subscribeEvents() {
 		SubscriptionList.allLists.forEach { list ->
-			runCatching {
-				list.provideSubscriptions {
-					it.owner.javaClass.classes.forEach {
-						runCatching { it.getDeclaredField("INSTANCE").get(null) }
+			if (ICompatMeta.shouldLoad(list.javaClass.name))
+				runCatching {
+					list.provideSubscriptions {
+						it.owner.javaClass.classes.forEach {
+							runCatching { it.getDeclaredField("INSTANCE").get(null) }
+						}
+						subscribeSingleEvent(it)
 					}
-					subscribeSingleEvent(it)
+				}.getOrElse {
+					// TODO: allow annotating source sets to specifically opt out of loading for mods, maybe automatically
+					Firmament.logger.info("Ignoring events from $list, likely due to a missing compat mod.", it)
 				}
-			}.getOrElse {
-				// TODO: allow annotating source sets to specifically opt out of loading for mods, maybe automatically
-				Firmament.logger.info("Ignoring events from $list, likely due to a missing compat mod.", it)
-			}
 		}
 	}
 

src/main/kotlin/util/compatloader/CompatLoader.kt

@@ -6,7 +6,7 @@ import kotlin.reflect.KClass
 import kotlin.streams.asSequence
 import moe.nea.firmament.Firmament
 
-abstract class CompatLoader<T : Any>(val kClass: Class<T>) {
+open class CompatLoader<T : Any>(val kClass: Class<T>) {
 	constructor(kClass: KClass<T>) : this(kClass.java)
 
 	val loader: ServiceLoader<T> = ServiceLoader.load(kClass)

src/main/kotlin/util/compatloader/CompatMeta.kt

@@ -0,0 +1,48 @@
+package moe.nea.firmament.util.compatloader
+
+import java.util.ServiceLoader
+import moe.nea.firmament.events.subscription.SubscriptionList
+import moe.nea.firmament.init.AutoDiscoveryPlugin
+import moe.nea.firmament.util.ErrorUtil
+
+/**
+ * Declares the compat meta interface for the current source set.
+ * This is used by [CompatLoader], [SubscriptionList], and [AutoDiscoveryPlugin]. Annotate a [ICompatMeta] object with
+ * this.
+ */
+annotation class CompatMeta
+
+interface ICompatMetaGen {
+	fun owns(className: String): Boolean
+	val meta: ICompatMeta
+}
+
+interface ICompatMeta {
+	fun shouldLoad(): Boolean
+
+	companion object {
+		val allMetas = ServiceLoader
+			.load(ICompatMetaGen::class.java)
+			.toList()
+
+		fun shouldLoad(className: String): Boolean {
+			// TODO: replace this with a more performant package lookup
+			val meta = if (ErrorUtil.aggressiveErrors) {
+				val fittingMetas = allMetas.filter { it.owns(className) }
+				require(fittingMetas.size == 1) { "Orphaned or duplicate owned class $className (${fittingMetas.map { it.meta }}). Consider adding a @CompatMeta object." }
+				fittingMetas.single()
+			} else {
+				allMetas.firstOrNull { it.owns(className) }
+			}
+			return meta?.meta?.shouldLoad() ?: true
+		}
+	}
+}
+
+object CompatHelper {
+	fun isOwnedByPackage(className: String, vararg packages: String): Boolean {
+		// TODO: create package lookup structure once
+		val packageName = className.substringBeforeLast('.')
+		return packageName in packages
+	}
+}