Add special case for handling place event with lilies. Fixes BUKKIT-5641

src/main/java/net/minecraft/server/ItemWaterLily.java

@@ -26,7 +26,15 @@ public class ItemWaterLily extends ItemWithAuxData {
                 }
 
                 if (world.getType(i, j, k).getMaterial() == Material.WATER && world.getData(i, j, k) == 0 && world.isEmpty(i, j + 1, k)) {
+                    // CraftBukkit start - special case for handling block placement with water lilies
+                    org.bukkit.block.BlockState blockstate = org.bukkit.craftbukkit.block.CraftBlockState.getBlockState(world, i, j + 1, k);
                     world.setTypeUpdate(i, j + 1, k, Blocks.WATER_LILY);
+                    org.bukkit.event.block.BlockPlaceEvent placeEvent = org.bukkit.craftbukkit.event.CraftEventFactory.callBlockPlaceEvent(world, entityhuman, blockstate, i, j, k);
+                    if (placeEvent != null && (placeEvent.isCancelled() || !placeEvent.canBuild())) {
+                        blockstate.update(true, false);
+                        return itemstack;
+                    }
+                    // CraftBukkit end
 
                     if (!entityhuman.abilities.canInstantlyBuild) {
                         --itemstack.count;

src/main/java/net/minecraft/server/PlayerConnection.java

@@ -610,7 +610,7 @@ public class PlayerConnection implements PacketPlayInListener {
             // CraftBukkit - notch decrements the counter by 1 in the above method with food,
             // snowballs and so forth, but he does it in a place that doesn't cause the
             // inventory update packet to get sent
-            always = (itemstack.count != itemstackAmount);
+            always = (itemstack.count != itemstackAmount) || itemstack.getItem() == Item.getItemOf(Blocks.WATER_LILY);
             // CraftBukkit end
         } else if (packetplayinblockplace.d() >= this.minecraftServer.getMaxBuildHeight() - 1 && (packetplayinblockplace.getFace() == 1 || packetplayinblockplace.d() >= this.minecraftServer.getMaxBuildHeight())) {
             ChatMessage chatmessage = new ChatMessage("build.tooHigh", new Object[] { Integer.valueOf(this.minecraftServer.getMaxBuildHeight())});