PaperMC/paper-server/nms-patches/net/minecraft/world/level/block/BlockPressurePlateAbstract.patch

--- a/net/minecraft/world/level/block/BlockPressurePlateAbstract.java
+++ b/net/minecraft/world/level/block/BlockPressurePlateAbstract.java
@@ -23,6 +23,8 @@
 import net.minecraft.world.phys.shapes.VoxelShape;
 import net.minecraft.world.phys.shapes.VoxelShapeCollision;
 
+import org.bukkit.event.block.BlockRedstoneEvent; // CraftBukkit
+
 public abstract class BlockPressurePlateAbstract extends Block {
 
     protected static final VoxelShape PRESSED_AABB = Block.box(1.0D, 0.0D, 1.0D, 15.0D, 0.5D, 15.0D);
@@ -91,6 +93,19 @@
         boolean flag = i > 0;
         boolean flag1 = j > 0;
 
+        // CraftBukkit start - Interact Pressure Plate
+        org.bukkit.World bworld = world.getWorld();
+        org.bukkit.plugin.PluginManager manager = world.getCraftServer().getPluginManager();
+
+        if (flag != flag1) {
+            BlockRedstoneEvent eventRedstone = new BlockRedstoneEvent(bworld.getBlockAt(blockposition.getX(), blockposition.getY(), blockposition.getZ()), i, j);
+            manager.callEvent(eventRedstone);
+
+            flag1 = eventRedstone.getNewCurrent() > 0;
+            j = eventRedstone.getNewCurrent();
+        }
+        // CraftBukkit end
+
         if (i != j) {
             IBlockData iblockdata1 = this.setSignalForState(iblockdata, j);
 
@@ -145,9 +160,15 @@
     }
 
     protected static int getEntityCount(World world, AxisAlignedBB axisalignedbb, Class<? extends Entity> oclass) {
+        // CraftBukkit start
+        return getEntities(world, axisalignedbb, oclass).size();
+    }
+
+    protected static <T extends Entity> java.util.List<T> getEntities(World world, AxisAlignedBB axisalignedbb, Class<T> oclass) {
+        // CraftBukkit end
         return world.getEntitiesOfClass(oclass, axisalignedbb, IEntitySelector.NO_SPECTATORS.and((entity) -> {
             return !entity.isIgnoringBlockTriggers();
-        })).size();
+        })); // CraftBukkit
     }
 
     protected abstract int getSignalStrength(World world, BlockPosition blockposition);