Water mobs should only spawn in the water

Closes GH-199

Spigot-Server-Patches/0139-Water-mobs-should-only-spawn-in-the-water.patch

@@ -0,0 +1,30 @@
+From d4985b594d55ee94ef5b68677eda3496d6cd8149 Mon Sep 17 00:00:00 2001
+From: Zach Brown <zach.brown@destroystokyo.com>
+Date: Thu, 14 Apr 2016 17:48:56 -0500
+Subject: [PATCH] Water mobs should only spawn in the water
+
+
+diff --git a/src/main/java/net/minecraft/server/EntityWaterAnimal.java b/src/main/java/net/minecraft/server/EntityWaterAnimal.java
+index f4764da..2aa0391 100644
+--- a/src/main/java/net/minecraft/server/EntityWaterAnimal.java
++++ b/src/main/java/net/minecraft/server/EntityWaterAnimal.java
+@@ -11,7 +11,15 @@ public abstract class EntityWaterAnimal extends EntityInsentient implements IAni
+     }
+ 
+     public boolean cF() {
+-        return true;
++        // Paper start - Don't let water mobs spawn in non-water blocks
++        // Based around EntityAnimal's implementation
++        int i = MathHelper.floor(this.locX);
++        int j = MathHelper.floor(this.getBoundingBox().b); // minY of bounding box
++        int k = MathHelper.floor(this.locZ);
++        Block below = this.world.getType(new BlockPosition(i, j, k).down()).getBlock();
++
++        return below == Blocks.WATER || below == Blocks.FLOWING_WATER;
++        // Paper end
+     }
+ 
+     public boolean canSpawn() {
+-- 
+2.8.0
+

scripts/importmcdev.sh

@@ -51,6 +51,7 @@ import DataBits
 import DataConverterMaterialId
 import EULA
 import EntitySquid
+import EntityWaterAnimal
 import FileIOThread
 import ItemBlock
 import PacketPlayInResourcePackStatus