PaperMC/nms-patches/BlockRedstoneWire.patch

--- a/net/minecraft/server/BlockRedstoneWire.java
+++ b/net/minecraft/server/BlockRedstoneWire.java
@@ -9,6 +9,8 @@
 import java.util.Set;
 import javax.annotation.Nullable;
 
+import org.bukkit.event.block.BlockRedstoneEvent; // CraftBukkit
+
 public class BlockRedstoneWire extends Block {
 
     public static final BlockStateEnum<BlockPropertyRedstoneSide> NORTH = BlockProperties.X;
@@ -213,7 +215,16 @@
     private void a(World world, BlockPosition blockposition, IBlockData iblockdata) {
         int i = this.a(world, blockposition);
 
-        if ((Integer) iblockdata.get(BlockRedstoneWire.POWER) != i) {
+        // CraftBukkit start
+        int oldPower = (Integer) iblockdata.get(BlockRedstoneWire.POWER);
+        if (oldPower != i) {
+            BlockRedstoneEvent event = new BlockRedstoneEvent(world.getWorld().getBlockAt(blockposition.getX(), blockposition.getY(), blockposition.getZ()), oldPower, i);
+            world.getServer().getPluginManager().callEvent(event);
+
+            i = event.getNewCurrent();
+        }
+        if (oldPower != i) {
+            // CraftBukkit end
             if (world.getType(blockposition) == iblockdata) {
                 world.setTypeAndData(blockposition, (IBlockData) iblockdata.set(BlockRedstoneWire.POWER, i), 2);
             }