PaperMC/paper-server/nms-patches/BlockEnderPortal.patch

--- a/net/minecraft/server/BlockEnderPortal.java
+++ b/net/minecraft/server/BlockEnderPortal.java
@@ -1,5 +1,10 @@
 package net.minecraft.server;
 
+// CraftBukkit start
+import org.bukkit.event.entity.EntityPortalEnterEvent;
+import org.bukkit.event.player.PlayerTeleportEvent;
+// CraftBukkit end
+
 public class BlockEnderPortal extends BlockTileEntity {
 
     protected static final VoxelShape a = Block.a(0.0D, 0.0D, 0.0D, 16.0D, 12.0D, 16.0D);
@@ -21,13 +26,22 @@
     @Override
     public void a(IBlockData iblockdata, World world, BlockPosition blockposition, Entity entity) {
         if (world instanceof WorldServer && !entity.isPassenger() && !entity.isVehicle() && entity.canPortal() && VoxelShapes.c(VoxelShapes.a(entity.getBoundingBox().d((double) (-blockposition.getX()), (double) (-blockposition.getY()), (double) (-blockposition.getZ()))), iblockdata.getShape(world, blockposition), OperatorBoolean.AND)) {
-            ResourceKey<World> resourcekey = world.getDimensionKey() == World.THE_END ? World.OVERWORLD : World.THE_END;
+            ResourceKey<World> resourcekey = world.getTypeKey() == DimensionManager.THE_END ? World.OVERWORLD : World.THE_END; // CraftBukkit - SPIGOT-6152: send back to main overworld in custom ends
             WorldServer worldserver = ((WorldServer) world).getMinecraftServer().getWorldServer(resourcekey);
 
             if (worldserver == null) {
-                return;
+                // return; // CraftBukkit - always fire event in case plugins wish to change it
             }
 
+            // CraftBukkit start - Entity in portal
+            EntityPortalEnterEvent event = new EntityPortalEnterEvent(entity.getBukkitEntity(), new org.bukkit.Location(world.getWorld(), blockposition.getX(), blockposition.getY(), blockposition.getZ()));
+            world.getServer().getPluginManager().callEvent(event);
+
+            if (entity instanceof EntityPlayer) {
+                ((EntityPlayer) entity).b(worldserver, PlayerTeleportEvent.TeleportCause.END_PORTAL);
+                return;
+            }
+            // CraftBukkit end
             entity.b(worldserver);
         }