From 73b2c3c20ccc27d497278a7c02be9dcebbacdf6e Mon Sep 17 00:00:00 2001
From: Lizbeth Rika <vazkii@hotmail.com>
Date: Mon, 20 Jul 2015 23:16:04 +0100
Subject: [PATCH] Use a copy list to check for coordinates in the force relay.
 Closes #1188

---
 .../vazkii/botania/common/block/BlockPistonRelay.java     | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/src/main/java/vazkii/botania/common/block/BlockPistonRelay.java b/src/main/java/vazkii/botania/common/block/BlockPistonRelay.java
index e61d0f6f0..27883721b 100644
--- a/src/main/java/vazkii/botania/common/block/BlockPistonRelay.java
+++ b/src/main/java/vazkii/botania/common/block/BlockPistonRelay.java
@@ -196,8 +196,9 @@ public class BlockPistonRelay extends BlockMod implements IWandable, ILexiconabl
 
 	@SubscribeEvent
 	public void tickEnd(TickEvent event) {
-		if(event.type == Type.SERVER && event.phase == Phase.END)
-			for(String s : coordsToCheck.keySet()) {
+		if(event.type == Type.SERVER && event.phase == Phase.END) {
+			List<String> coordsToCheckCopy = new ArrayList(coordsToCheck.keySet());
+			for(String s : coordsToCheckCopy) {
 				decrCoords(s);
 				if(checkedCoords.contains(s))
 					continue;
@@ -255,7 +256,8 @@ public class BlockPistonRelay extends BlockMod implements IWandable, ILexiconabl
 					}
 				}
 			}
-
+		}
+			
 		// ConcurrentModificationException failsafe
 		ArrayList<String> remove = new ArrayList(removeThese);
 		for(String s : remove) {