Paper/nms-patches/ItemBlock.patch

--- a/net/minecraft/server/ItemBlock.java
+++ b/net/minecraft/server/ItemBlock.java
@@ -3,6 +3,11 @@
 import java.util.Iterator;
 import java.util.Map;
 import javax.annotation.Nullable;
+// CraftBukkit start
+import org.bukkit.craftbukkit.block.CraftBlock;
+import org.bukkit.craftbukkit.block.data.CraftBlockData;
+import org.bukkit.event.block.BlockCanBuildEvent;
+// CraftBukkit end
 
 public class ItemBlock extends Item {
 
@@ -55,7 +60,7 @@
 
                     SoundEffectType soundeffecttype = iblockdata1.r();
 
-                    world.a(entityhuman, blockposition, this.a(iblockdata1), SoundCategory.BLOCKS, (soundeffecttype.a() + 1.0F) / 2.0F, soundeffecttype.b() * 0.8F);
+                    // world.a(entityhuman, blockposition, this.a(iblockdata1), SoundCategory.BLOCKS, (soundeffecttype.a() + 1.0F) / 2.0F, soundeffecttype.b() * 0.8F);
                     itemstack.subtract(1);
                     return EnumInteractionResult.SUCCESS;
                 }
@@ -120,8 +125,15 @@
     protected boolean b(BlockActionContext blockactioncontext, IBlockData iblockdata) {
         EntityHuman entityhuman = blockactioncontext.getEntity();
         VoxelShapeCollision voxelshapecollision = entityhuman == null ? VoxelShapeCollision.a() : VoxelShapeCollision.a((Entity) entityhuman);
+        // CraftBukkit start - store default return
+        boolean defaultReturn = (!this.d() || iblockdata.canPlace(blockactioncontext.getWorld(), blockactioncontext.getClickPosition())) && blockactioncontext.getWorld().a(iblockdata, blockactioncontext.getClickPosition(), voxelshapecollision);
+        org.bukkit.entity.Player player = (blockactioncontext.getEntity() instanceof EntityPlayer) ? (org.bukkit.entity.Player) blockactioncontext.getEntity().getBukkitEntity() : null;
 
-        return (!this.d() || iblockdata.canPlace(blockactioncontext.getWorld(), blockactioncontext.getClickPosition())) && blockactioncontext.getWorld().a(iblockdata, blockactioncontext.getClickPosition(), voxelshapecollision);
+        BlockCanBuildEvent event = new BlockCanBuildEvent(CraftBlock.at(blockactioncontext.getWorld(), blockactioncontext.getClickPosition()), player, CraftBlockData.fromData(iblockdata), defaultReturn);
+        blockactioncontext.getWorld().getServer().getPluginManager().callEvent(event);
+
+        return event.isBuildable();
+        // CraftBukkit end
     }
 
     protected boolean d() {