Paper/nms-patches/BlockPortalShape.patch

--- a/net/minecraft/server/BlockPortalShape.java
+++ b/net/minecraft/server/BlockPortalShape.java
@@ -4,6 +4,13 @@
 import java.util.function.Predicate;
 import javax.annotation.Nullable;
 
+// CraftBukkit start
+import org.bukkit.craftbukkit.block.CraftBlock;
+import org.bukkit.craftbukkit.block.CraftBlockState;
+import org.bukkit.event.entity.EntityPortalEnterEvent;
+import org.bukkit.event.world.PortalCreateEvent;
+// CraftBukkit end
+
 public class BlockPortalShape {
 
     private static final BlockBase.e a = (iblockdata, iblockaccess, blockposition) -> {
@@ -17,6 +24,7 @@
     private BlockPosition position;
     private int height;
     private int width;
+    java.util.List<org.bukkit.block.BlockState> blocks = new java.util.ArrayList<org.bukkit.block.BlockState>(); // CraftBukkit - add field
 
     public static Optional<BlockPortalShape> a(GeneratorAccess generatoraccess, BlockPosition blockposition, EnumDirection.EnumAxis enumdirection_enumaxis) {
         return a(generatoraccess, blockposition, (blockportalshape) -> {
@@ -81,6 +89,7 @@
 
             if (!a(iblockdata)) {
                 if (BlockPortalShape.a.test(iblockdata, this.b, blockposition_mutableblockposition)) {
+                    blocks.add(CraftBlock.at(this.b, blockposition_mutableblockposition).getState()); // CraftBukkit
                     return i;
                 }
                 break;
@@ -152,12 +161,30 @@
         return this.position != null && this.width >= 2 && this.width <= 21 && this.height >= 3 && this.height <= 21;
     }
 
-    public void createPortal() {
+    // CraftBukkit start - return boolean
+    public boolean createPortal() {
+        org.bukkit.World bworld = this.b.getMinecraftWorld().getWorld();
+
+        // Copy below for loop
         IBlockData iblockdata = (IBlockData) Blocks.NETHER_PORTAL.getBlockData().set(BlockPortal.AXIS, this.c);
 
         BlockPosition.a(this.position, this.position.shift(EnumDirection.UP, this.height - 1).shift(this.d, this.width - 1)).forEach((blockposition) -> {
+            CraftBlockState state = CraftBlockState.getBlockState(this.b.getMinecraftWorld(), blockposition, 18);
+            state.setData(iblockdata);
+            blocks.add(state);
+        });
+
+        PortalCreateEvent event = new PortalCreateEvent(blocks, bworld, null, PortalCreateEvent.CreateReason.FIRE);
+        this.b.getMinecraftWorld().getMinecraftServer().server.getPluginManager().callEvent(event);
+
+        if (event.isCancelled()) {
+            return false;
+        }
+        // CraftBukkit end
+        BlockPosition.a(this.position, this.position.shift(EnumDirection.UP, this.height - 1).shift(this.d, this.width - 1)).forEach((blockposition) -> {
             this.b.setTypeAndData(blockposition, iblockdata, 18);
         });
+        return true; // CraftBukkit
     }
 
     public boolean c() {
@@ -208,6 +235,6 @@
         boolean flag = enumdirection_enumaxis1 == EnumDirection.EnumAxis.X;
         Vec3D vec3d3 = new Vec3D((double) blockposition.getX() + (flag ? d2 : d4), (double) blockposition.getY() + d3, (double) blockposition.getZ() + (flag ? d4 : d2));
 
-        return new ShapeDetectorShape(vec3d3, vec3d2, f + (float) i, f1);
+        return new ShapeDetectorShape(vec3d3, vec3d2, f + (float) i, f1, worldserver); // CraftBukkit
     }
 }