PaperMC/paper-server/patches/sources/net/minecraft/server/commands/TeleportCommand.java.patch

--- a/net/minecraft/server/commands/TeleportCommand.java
+++ b/net/minecraft/server/commands/TeleportCommand.java
@@ -290,7 +_,31 @@
             float f1 = relatives.contains(Relative.X_ROT) ? xRot - target.getXRot() : xRot;
             float f2 = Mth.wrapDegrees(f);
             float f3 = Mth.wrapDegrees(f1);
-            if (target.teleportTo(level, d, d1, d2, relatives, f2, f3, true)) {
+            // CraftBukkit start - Teleport event
+            boolean result;
+            if (target instanceof final net.minecraft.server.level.ServerPlayer player) {
+                result = player.teleportTo(level, d, d1, d2, relatives, f2, f3, true, org.bukkit.event.player.PlayerTeleportEvent.TeleportCause.COMMAND);
+            } else {
+                org.bukkit.Location to = new org.bukkit.Location(level.getWorld(), d, d1, d2, f2, f3);
+                org.bukkit.event.entity.EntityTeleportEvent event = new org.bukkit.event.entity.EntityTeleportEvent(target.getBukkitEntity(), target.getBukkitEntity().getLocation(), to);
+                level.getCraftServer().getPluginManager().callEvent(event);
+                if (event.isCancelled() || event.getTo() == null) { // Paper
+                    return;
+                }
+                to = event.getTo(); // Paper - actually track new location
+
+                d = to.getX();
+                d1 = to.getY();
+                d2 = to.getZ();
+                f2 = to.getYaw();
+                f3 = to.getPitch();
+                level = ((org.bukkit.craftbukkit.CraftWorld) to.getWorld()).getHandle();
+
+                result = target.teleportTo(level, d, d1, d2, relatives, f2, f3, true);
+            }
+
+            if (result) {
+                // CraftBukkit end
                 if (lookAt != null) {
                     lookAt.perform(source, target);
                 }