From 03dfef00c43e4e29bcc1a67ea0b2cc6ce82776b6 Mon Sep 17 00:00:00 2001
From: DBotThePony <dbotthepony@yandex.ru>
Date: Sat, 29 Mar 2025 20:30:38 +0700
Subject: [PATCH] ???

---
 .../otm/block/entity/cable/EnergyCableGraph.kt   | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/src/main/kotlin/ru/dbotthepony/mc/otm/block/entity/cable/EnergyCableGraph.kt b/src/main/kotlin/ru/dbotthepony/mc/otm/block/entity/cable/EnergyCableGraph.kt
index aa754d4a7..f837fe360 100644
--- a/src/main/kotlin/ru/dbotthepony/mc/otm/block/entity/cable/EnergyCableGraph.kt
+++ b/src/main/kotlin/ru/dbotthepony/mc/otm/block/entity/cable/EnergyCableGraph.kt
@@ -20,6 +20,7 @@ import ru.dbotthepony.mc.otm.graph.GraphNodeList
 import ru.dbotthepony.mc.otm.onceServer
 import java.util.*
 import java.util.concurrent.atomic.AtomicLong
+import kotlin.ConcurrentModificationException
 import kotlin.collections.ArrayList
 import kotlin.collections.HashSet
 import kotlin.collections.LinkedHashSet
@@ -84,6 +85,9 @@ class EnergyCableGraph : GraphNodeList<EnergyCableBlockEntity.Node, EnergyCableG
 			ContainsStatus.ABOUT_TO_BE_REMOVED, ContainsStatus.ABOUT_TO_BE_ADDED -> { } // do nothing
 			ContainsStatus.DOES_NOT_BELONG -> throw IllegalArgumentException("$node does not belong to $this")
 			ContainsStatus.CONTAINS -> {
+				if (isIteratingNodes)
+					throw ConcurrentModificationException("Bug trap: currently iterating energy receivers!")
+
 				for (dir in RelativeSide.entries) {
 					val pair = node to dir
 
@@ -590,6 +594,9 @@ class EnergyCableGraph : GraphNodeList<EnergyCableBlockEntity.Node, EnergyCableG
 	}
 
 	override fun onNodeRemoved(node: EnergyCableBlockEntity.Node) {
+		if (isIteratingNodes)
+			throw ConcurrentModificationException("Bug trap: currently iterating energy receivers!")
+
 		for (dir in RelativeSide.entries) {
 			val pair = node to dir
 
@@ -618,6 +625,9 @@ class EnergyCableGraph : GraphNodeList<EnergyCableBlockEntity.Node, EnergyCableG
 	}
 
 	override fun onNodeAdded(node: EnergyCableBlockEntity.Node) {
+		if (isIteratingNodes)
+			throw ConcurrentModificationException("Bug trap: currently iterating energy receivers!")
+
 		for (dir in RelativeSide.entries) {
 			val pair = node to dir
 			check(livelyNodes.add(pair))
@@ -627,6 +637,8 @@ class EnergyCableGraph : GraphNodeList<EnergyCableBlockEntity.Node, EnergyCableG
 		notifyThroughputsChanged()
 	}
 
+	private var isIteratingNodes = false
+
 	fun receiveEnergy(howMuch: Decimal, simulate: Boolean, fromNode: EnergyCableBlockEntity.Node, fromSide: RelativeSide): Decimal {
 		livelyNodesList.shuffle(fromNode.blockEntity.level!!.otmRandom)
 
@@ -635,6 +647,8 @@ class EnergyCableGraph : GraphNodeList<EnergyCableBlockEntity.Node, EnergyCableG
 		var residue = howMuch.coerceAtMost(fromNode.energyThroughput)
 		val snapshot = Reference2ObjectOpenHashMap<Segment, Decimal>()
 
+		isIteratingNodes = true
+
 		for (pair in itr) {
 			// recursion prevention
 			if (!fromNode.currentlyTransferringTo.add(pair))
@@ -737,6 +751,8 @@ class EnergyCableGraph : GraphNodeList<EnergyCableBlockEntity.Node, EnergyCableG
 			}
 		}
 
+		isIteratingNodes = false
+
 		return received
 	}