Add entity knockback events

- EntityKnockbackEvent
- EntityPushedByEntityAttackEvent
- EntityKnockbackByEntityEvent

Co-authored-by: aerulion <aerulion@gmail.com>
Co-authored-by: Jake Potrebic <jake.m.potrebic@gmail.com>

paper-server/patches/sources/net/minecraft/world/entity/monster/Ravager.java.patch

@@ -22,3 +22,12 @@
                              flag = worldserver.destroyBlock(blockposition, true, this) || flag;
                          }
                      }
+@@ -281,7 +289,7 @@
+         double d1 = entity.getZ() - this.getZ();
+         double d2 = Math.max(d0 * d0 + d1 * d1, 0.001D);
+ 
+-        entity.push(d0 / d2 * 4.0D, 0.2D, d1 / d2 * 4.0D);
++        entity.push(d0 / d2 * 4.0D, 0.2D, d1 / d2 * 4.0D, this); // Paper - Add EntityKnockbackByEntityEvent and EntityPushedByEntityAttackEvent
+     }
+ 
+     @Override

paper-server/patches/sources/net/minecraft/world/entity/monster/creaking/Creaking.java.patch

@@ -1,6 +1,16 @@
 --- a/net/minecraft/world/entity/monster/creaking/Creaking.java
 +++ b/net/minecraft/world/entity/monster/creaking/Creaking.java
-@@ -206,7 +206,7 @@
+@@ -198,15 +198,15 @@
+     }
+ 
+     @Override
+-    public void push(double deltaX, double deltaY, double deltaZ) {
++    public void push(double deltaX, double deltaY, double deltaZ, @Nullable Entity pushingEntity) { // Paper - add push source entity param
+         if (this.canMove()) {
+-            super.push(deltaX, deltaY, deltaZ);
++            super.push(deltaX, deltaY, deltaZ, pushingEntity); // Paper - add push source entity param
+         }
+     }
  
      @Override
      public Brain<Creaking> getBrain() {
@@ -27,6 +37,18 @@
      }
  
      @Override
+@@ -502,9 +502,9 @@
+     }
+ 
+     @Override
+-    public void knockback(double strength, double x, double z) {
++    public void knockback(double strength, double x, double z, @Nullable Entity attacker, io.papermc.paper.event.entity.EntityKnockbackEvent.Cause cause) { // Paper - knockback events
+         if (this.canMove()) {
+-            super.knockback(strength, x, z);
++            super.knockback(strength, x, z, attacker, cause); // Paper - knockback events
+         }
+     }
+ 
 @@ -549,7 +549,7 @@
      }
  

paper-server/patches/sources/net/minecraft/world/entity/monster/hoglin/HoglinBase.java.patch

@@ -0,0 +1,11 @@
+--- a/net/minecraft/world/entity/monster/hoglin/HoglinBase.java
++++ b/net/minecraft/world/entity/monster/hoglin/HoglinBase.java
+@@ -45,7 +45,7 @@
+             double j = f * (double)(attacker.level().random.nextFloat() * 0.5F + 0.2F);
+             Vec3 vec3 = new Vec3(g, 0.0, h).normalize().scale(j).yRot(i);
+             double k = f * (double)attacker.level().random.nextFloat() * 0.5;
+-            target.push(vec3.x, k, vec3.z);
++            target.push(vec3.x, k, vec3.z, attacker); // Paper - Add EntityKnockbackByEntityEvent and EntityPushedByEntityAttackEvent
+             target.hurtMarked = true;
+         }
+     }