Revert previous changes to explosion event handling.

Event abstraction sucks and everything needs rewriting.

worldguard-bukkit/src/main/java/com/sk89q/worldguard/bukkit/event/block/AbstractBlockEvent.java

@@ -45,7 +45,7 @@
  * This event is an internal event. We do not recommend handling or throwing
  * this event or its subclasses as the interface is highly subject to change.
  */
-public abstract class AbstractBlockEvent extends DelegateEvent implements BulkEvent {
+abstract class AbstractBlockEvent extends DelegateEvent implements BulkEvent {
 
     private final World world;
     private List<Block> blocks;

worldguard-bukkit/src/main/java/com/sk89q/worldguard/bukkit/listener/EventAbstractionListener.java

@@ -25,7 +25,6 @@
 import com.sk89q.worldguard.bukkit.WorldGuardPlugin;
 import com.sk89q.worldguard.bukkit.cause.Cause;
 import com.sk89q.worldguard.bukkit.event.DelegateEvent;
-import com.sk89q.worldguard.bukkit.event.block.AbstractBlockEvent;
 import com.sk89q.worldguard.bukkit.event.block.BreakBlockEvent;
 import com.sk89q.worldguard.bukkit.event.block.PlaceBlockEvent;
 import com.sk89q.worldguard.bukkit.event.block.UseBlockEvent;
@@ -116,6 +115,7 @@
 import org.bukkit.event.entity.EntityDamageByEntityEvent;
 import org.bukkit.event.entity.EntityDamageEvent;
 import org.bukkit.event.entity.EntityDeathEvent;
+import org.bukkit.event.entity.EntityEvent;
 import org.bukkit.event.entity.EntityExplodeEvent;
 import org.bukkit.event.entity.EntityInteractEvent;
 import org.bukkit.event.entity.EntityKnockbackByEntityEvent;
@@ -181,9 +181,11 @@ public EventAbstractionListener(WorldGuardPlugin plugin) {
     public void registerEvents() {
         super.registerEvents();
 
+        PluginManager pm = getPlugin().getServer().getPluginManager();
         if (PaperLib.isPaper()) {
-            PluginManager pm = getPlugin().getServer().getPluginManager();
             pm.registerEvents(new EventAbstractionListener.PaperListener(), getPlugin());
+        } else {
+            pm.registerEvents(new EventAbstractionListener.SpigotListener(), getPlugin());
         }
     }
 
@@ -359,10 +361,7 @@ public void onEntityChangeBlock(EntityChangeBlockEvent event) {
 
     }
 
-    @EventHandler(ignoreCancelled = true)
+    private static <T  extends EntityEvent & Cancellable> void handleKnockback(T event, Entity damager) {
-    public void onEntityKnockbackByEntity(EntityKnockbackByEntityEvent event) {
-        Entity damager = event.getSourceEntity();
-
         final DamageEntityEvent eventToFire = new DamageEntityEvent(event, create(damager), event.getEntity());
         if (damager instanceof BreezeWindCharge) {
             eventToFire.getRelevantFlags().add(Flags.BREEZE_WIND_CHARGE);
@@ -372,24 +371,19 @@ public void onEntityKnockbackByEntity(EntityKnockbackByEntityEvent event) {
         Events.fireToCancel(event, eventToFire);
     }
 
+    @SuppressWarnings("UnstableApiUsage")
     @EventHandler(ignoreCancelled = true)
     public void onEntityExplode(EntityExplodeEvent event) {
         Entity entity = event.getEntity();
-        AbstractBlockEvent wgEvent;
-
         if (event.getExplosionResult() == ExplosionResult.TRIGGER_BLOCK) {
-            wgEvent = new UseBlockEvent(event, create(entity), event.getLocation().getWorld(), event.blockList(), Material.AIR);
+            UseBlockEvent useEvent = new UseBlockEvent(event, create(entity), event.getLocation().getWorld(), event.blockList(), Material.AIR);
+            useEvent.getRelevantFlags().add(Entities.getExplosionFlag(entity));
+            useEvent.setSilent(true);
+            Events.fireBulkEventToCancel(event, useEvent);
         } else if (event.getExplosionResult() == ExplosionResult.DESTROY || event.getExplosionResult() == ExplosionResult.DESTROY_WITH_DECAY) {
-            wgEvent = new BreakBlockEvent(event, create(entity), event.getLocation().getWorld(), event.blockList(), Material.AIR);
+            Events.fireBulkEventToCancel(event, new BreakBlockEvent(event, create(entity), event.getLocation().getWorld(), event.blockList(), Material.AIR));
-        } else {
-            return;
         }
 
-        wgEvent.getRelevantFlags().add(Entities.getExplosionFlag(event.getEntity()));
-
-        wgEvent.setSilent(true);
-        Events.fireBulkEventToCancel(event, wgEvent);
-
         if (entity instanceof Creeper) {
             Cause.untrackParentCause(entity);
         }
@@ -1295,7 +1289,7 @@ private static void playDenyEffect(Location location) {
         }
     }
 
-    private class PaperListener implements Listener {
+    private static class PaperListener implements Listener {
         @EventHandler(ignoreCancelled = true)
         public void onEntityTransform(EntityZapEvent event) {
             Events.fireToCancel(event, new DamageEntityEvent(event, create(event.getBolt()), event.getEntity()));
@@ -1308,5 +1302,18 @@ public void onSignOpen(PlayerOpenSignEvent event) {
                 Events.fireToCancel(event, new UseBlockEvent(event, create(event.getPlayer()), event.getSign().getBlock()));
             }
         }
+
+        @EventHandler(ignoreCancelled = true)
+        public void onEntityKnockbackByEntity(com.destroystokyo.paper.event.entity.EntityKnockbackByEntityEvent event) {
+            handleKnockback(event, event.getHitBy());
+        }
+    }
+
+    @SuppressWarnings("removal")
+    private static class SpigotListener implements Listener {
+        @EventHandler(ignoreCancelled = true)
+        public void onEntityKnockbackByEntity(EntityKnockbackByEntityEvent event) {
+            handleKnockback(event, event.getSourceEntity());
+        }
     }
 }

worldguard-bukkit/src/main/java/com/sk89q/worldguard/bukkit/listener/WorldGuardEntityListener.java

@@ -61,6 +61,7 @@
 import org.bukkit.entity.Projectile;
 import org.bukkit.entity.TNTPrimed;
 import org.bukkit.entity.Tameable;
+import org.bukkit.entity.WindCharge;
 import org.bukkit.entity.Wither;
 import org.bukkit.entity.WitherSkull;
 import org.bukkit.entity.Wolf;
@@ -503,6 +504,16 @@ public void onEntityExplode(EntityExplodeEvent event) {
                     return;
                 }
             }
+            if (wcfg.useRegions && !(ent instanceof WindCharge)) {
+                for (Block block : event.blockList()) {
+                    if (!WorldGuard.getInstance().getPlatform().getRegionContainer().createQuery()
+                            .testState(BukkitAdapter.adapt(block.getLocation()), null, Entities.getExplosionFlag(ent))) {
+                        event.blockList().clear();
+                        if (wcfg.explosionFlagCancellation) event.setCancelled(true);
+                        return;
+                    }
+                }
+            }
         } else if (ent instanceof Wither) {
             if (wcfg.blockWitherExplosions) {
                 event.setCancelled(true);
@@ -512,12 +523,32 @@ public void onEntityExplode(EntityExplodeEvent event) {
                 event.blockList().clear();
                 return;
             }
+            if (wcfg.useRegions) {
+                for (Block block : event.blockList()) {
+                    if (!WorldGuard.getInstance().getPlatform().getRegionContainer().createQuery()
+                            .testState(BukkitAdapter.adapt(block.getLocation()), null, Flags.WITHER_DAMAGE)) {
+                        event.blockList().clear();
+                        event.setCancelled(true);
+                        return;
+                    }
+                }
+            }
         } else {
             // unhandled entity
             if (wcfg.blockOtherExplosions) {
                 event.setCancelled(true);
                 return;
             }
+            if (wcfg.useRegions) {
+                for (Block block : event.blockList()) {
+                    if (!WorldGuard.getInstance().getPlatform().getRegionContainer().createQuery()
+                            .testState(BukkitAdapter.adapt(block.getLocation()), null, Flags.OTHER_EXPLOSION)) {
+                        event.blockList().clear();
+                        if (wcfg.explosionFlagCancellation) event.setCancelled(true);
+                        return;
+                    }
+                }
+            }
         }
 
         if (wcfg.signChestProtection) {

worldguard-bukkit/src/main/java/com/sk89q/worldguard/bukkit/util/Entities.java

@@ -246,7 +246,7 @@ public static boolean isAoECloud(EntityType type) {
      * This is true for custom creations or the summon command.
      *
      * @param spawnReason the reason
-     * @return true if considerd plugin spawning
+     * @return true if considered plugin spawning
      */
     public static boolean isPluginSpawning(CreatureSpawnEvent.SpawnReason spawnReason) {
         return switch (spawnReason) {