Remount players in their vehicle if they're not supposed to leave

core/src/main/java/org/geysermc/geyser/entity/type/Entity.java

@@ -44,8 +44,6 @@ import lombok.Setter;
 import net.kyori.adventure.text.Component;
 import org.geysermc.geyser.entity.EntityDefinition;
 import org.geysermc.geyser.entity.GeyserDirtyMetadata;
-import org.geysermc.geyser.entity.type.player.SessionPlayerEntity;
-import org.geysermc.geyser.network.GameProtocol;
 import org.geysermc.geyser.session.GeyserSession;
 import org.geysermc.geyser.translator.text.MessageTranslator;
 import org.geysermc.geyser.util.EntityUtils;

core/src/main/java/org/geysermc/geyser/session/GeyserSession.java

@@ -62,7 +62,6 @@ import com.github.steveice10.packetlib.event.session.*;
 import com.github.steveice10.packetlib.packet.Packet;
 import com.github.steveice10.packetlib.tcp.TcpClientSession;
 import com.github.steveice10.packetlib.tcp.TcpSession;
-import com.nukkitx.math.GenericMath;
 import com.nukkitx.math.vector.*;
 import com.nukkitx.nbt.NbtMap;
 import com.nukkitx.protocol.bedrock.BedrockPacket;
@@ -135,7 +134,6 @@ import org.geysermc.geyser.translator.text.MessageTranslator;
 import org.geysermc.geyser.util.ChunkUtils;
 import org.geysermc.geyser.util.DimensionUtils;
 import org.geysermc.geyser.util.LoginEncryptionUtils;
-import org.geysermc.geyser.util.MathUtils;
 
 import java.net.ConnectException;
 import java.net.InetSocketAddress;
@@ -539,6 +537,12 @@ public class GeyserSession implements GeyserConnection, GeyserCommandSource {
     @Setter
     private ScheduledFuture<?> lookBackScheduledFuture = null;
 
+    /**
+     * Used to return players back to their vehicles if the server doesn't want them unmounting.
+     */
+    @Setter
+    private ScheduledFuture<?> mountVehicleScheduledFuture = null;
+
     private MinecraftProtocol protocol;
 
     public GeyserSession(GeyserImpl geyser, BedrockServerSession bedrockServerSession, EventLoop eventLoop) {

core/src/main/java/org/geysermc/geyser/translator/protocol/bedrock/entity/player/BedrockInteractTranslator.java

@@ -32,15 +32,19 @@ import com.github.steveice10.mc.protocol.data.game.entity.type.EntityType;
 import com.github.steveice10.mc.protocol.packet.ingame.serverbound.player.ServerboundInteractPacket;
 import com.github.steveice10.mc.protocol.packet.ingame.serverbound.player.ServerboundPlayerCommandPacket;
 import com.nukkitx.protocol.bedrock.data.entity.EntityData;
+import com.nukkitx.protocol.bedrock.data.entity.EntityLinkData;
 import com.nukkitx.protocol.bedrock.data.inventory.ContainerType;
 import com.nukkitx.protocol.bedrock.packet.ContainerOpenPacket;
 import com.nukkitx.protocol.bedrock.packet.InteractPacket;
+import com.nukkitx.protocol.bedrock.packet.SetEntityLinkPacket;
 import org.geysermc.geyser.entity.type.Entity;
 import org.geysermc.geyser.entity.type.living.animal.horse.AbstractHorseEntity;
 import org.geysermc.geyser.session.GeyserSession;
 import org.geysermc.geyser.translator.protocol.PacketTranslator;
 import org.geysermc.geyser.translator.protocol.Translator;
 
+import java.util.concurrent.TimeUnit;
+
 @Translator(packet = InteractPacket.class)
 public class BedrockInteractTranslator extends PacketTranslator<InteractPacket> {
 
@@ -73,6 +77,23 @@ public class BedrockInteractTranslator extends PacketTranslator<InteractPacket>
             case LEAVE_VEHICLE:
                 ServerboundPlayerCommandPacket sneakPacket = new ServerboundPlayerCommandPacket(entity.getEntityId(), PlayerState.START_SNEAKING);
                 session.sendDownstreamPacket(sneakPacket);
+
+                Entity currentVehicle = session.getPlayerEntity().getVehicle();
+                session.setMountVehicleScheduledFuture(session.scheduleInEventLoop(() -> {
+                    if (session.getPlayerEntity().getVehicle() == null) {
+                        return;
+                    }
+
+                    long vehicleBedrockId = currentVehicle.getGeyserId();
+                    if (session.getPlayerEntity().getVehicle().getGeyserId() == vehicleBedrockId) {
+                        // The Bedrock client, as of 1.19.51, dismounts on its end. The server may not agree with this.
+                        // If the server doesn't agree with our dismount (sends a packet saying we dismounted),
+                        // then remount the player.
+                        SetEntityLinkPacket linkPacket = new SetEntityLinkPacket();
+                        linkPacket.setEntityLink(new EntityLinkData(vehicleBedrockId, session.getPlayerEntity().getGeyserId(), EntityLinkData.Type.PASSENGER, true, false));
+                        session.sendUpstreamPacket(linkPacket);
+                    }
+                }, 1, TimeUnit.SECONDS));
                 break;
             case MOUSEOVER:
                 // Handle the buttons for mobile - "Mount", etc; and the suggestions for console - "ZL: Mount", etc

core/src/main/java/org/geysermc/geyser/translator/protocol/java/entity/player/JavaPlayerPositionTranslator.java

@@ -114,6 +114,13 @@ public class JavaPlayerPositionTranslator extends PacketTranslator<ClientboundPl
             EntityUtils.updateRiderRotationLock(entity, null, false);
             EntityUtils.updateMountOffset(entity, null, false, false, entity.getPassengers().size() > 1);
             entity.updateBedrockMetadata();
+
+            if (session.getMountVehicleScheduledFuture() != null) {
+                // Cancel this task as it is now unnecessary.
+                // Note that this isn't present in JavaSetPassengersTranslator as that code is not called for players
+                // as of Java 1.19.3, but the scheduled future checks for the vehicle being null anyway.
+                session.getMountVehicleScheduledFuture().cancel(false);
+            }
         }
 
         // If coordinates are relative, then add to the existing coordinate