From 789be1bd63158936d36e9b45a76aa49f4a59e148 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Mon, 10 Sep 2018 23:36:16 -0400
Subject: [PATCH] Prevent chunk loading from Fluid Flowing


diff --git a/src/main/java/net/minecraft/server/FluidTypeFlowing.java b/src/main/java/net/minecraft/server/FluidTypeFlowing.java
index 8a6f79908..c1ed05d9e 100644
--- a/src/main/java/net/minecraft/server/FluidTypeFlowing.java
+++ b/src/main/java/net/minecraft/server/FluidTypeFlowing.java
@@ -186,7 +186,8 @@ public abstract class FluidTypeFlowing extends FluidType {
                 EnumDirection enumdirection = (EnumDirection) entry.getKey();
                 Fluid fluid1 = (Fluid) entry.getValue();
                 BlockPosition blockposition1 = blockposition.shift(enumdirection);
-                IBlockData iblockdata1 = generatoraccess.getType(blockposition1);
+                IBlockData iblockdata1 = generatoraccess.getTypeIfLoaded(blockposition1); // Paper
+                if (iblockdata1 == null) continue; // Paper
 
                 if (this.a(generatoraccess, blockposition, iblockdata, enumdirection, blockposition1, iblockdata1, generatoraccess.getFluid(blockposition1), fluid1.c())) {
                     // CraftBukkit start
@@ -213,7 +214,8 @@ public abstract class FluidTypeFlowing extends FluidType {
         while (iterator.hasNext()) {
             EnumDirection enumdirection = (EnumDirection) iterator.next();
             BlockPosition blockposition1 = blockposition.shift(enumdirection);
-            IBlockData iblockdata1 = iworldreader.getType(blockposition1);
+            IBlockData iblockdata1 = iworldreader.getTypeIfLoaded(blockposition1); // Paper
+            if (iblockdata1 == null) continue; // Paper
             Fluid fluid = iblockdata1.s();
 
             if (fluid.c().a((FluidType) this) && this.a(enumdirection, (IBlockAccess) iworldreader, blockposition, iblockdata, blockposition1, iblockdata1)) {
@@ -331,11 +333,19 @@ public abstract class FluidTypeFlowing extends FluidType {
                 BlockPosition blockposition2 = blockposition.shift(enumdirection1);
                 short short0 = a(blockposition1, blockposition2);
                 // CraftBukkit start - decompile errors
-                Pair pair = (Pair) short2objectmap.computeIfAbsent(short0, (ix) -> {
-                    IBlockData iblockdatax = iworldreader.getType(blockposition2);
+                // Paper start - avoid loading chunks
+                Pair<IBlockData, Fluid> pair = short2objectmap.get(short0);
+                if (pair == null) {
+                    IBlockData iblockdatax = iworldreader.getTypeIfLoaded(blockposition2);
+                    if (iblockdatax == null) {
+                        continue;
+                    }
 
-                    return Pair.of(iblockdatax, iblockdatax.s());
-                });
+                    pair = Pair.of(iblockdatax, iblockdatax.s());
+                    short2objectmap.put(short0, pair);
+
+                }
+                // Paper end
                 // CraftBukkit end
                 IBlockData iblockdata1 = (IBlockData) pair.getFirst();
                 Fluid fluid = (Fluid) pair.getSecond();
@@ -411,11 +421,16 @@ public abstract class FluidTypeFlowing extends FluidType {
             BlockPosition blockposition1 = blockposition.shift(enumdirection);
             short short0 = a(blockposition, blockposition1);
             // CraftBukkit start - decompile errors
-            Pair pair = (Pair) short2objectopenhashmap.computeIfAbsent(short0, (ix) -> {
-                IBlockData iblockdatax = iworldreader.getType(blockposition1);
-
-                return Pair.of(iblockdatax, iblockdatax.s());
-            });
+            // Paper start
+            Pair pair = (Pair) short2objectopenhashmap.get(short0);
+            if (pair == null) {
+                IBlockData iblockdatax = iworldreader.getTypeIfLoaded(blockposition1);
+                if (iblockdatax == null) continue;
+
+                pair = Pair.of(iblockdatax, iblockdatax.s());
+                short2objectopenhashmap.put(short0, pair);
+            }
+            // Paper end
             // CraftBukkit end
             IBlockData iblockdata1 = (IBlockData) pair.getFirst();
             Fluid fluid = (Fluid) pair.getSecond();
-- 
2.20.0