Redundant awaitingPositionFromClient check in handleMoveVehicle

Expected behavior

https://github.com/PaperMC/Paper/blob/daddcf67420e92ce1eba27949f3c847a92ffab14/paper-server/patches/sources/net/minecraft/server/network/ServerGamePacketListenerImpl.java.patch#L179

this kinda confused me until i realized its paper logic bug.

...
//ServerGamePacketListenerImpl.handleMoveVehicle()
 } else if (!this.updateAwaitingTeleport() && this.player.hasClientLoaded()) {
            Entity rootVehicle = this.player.getRootVehicle();
            // Paper start - Don't allow vehicle movement from players while teleporting
            if (this.awaitingPositionFromClient != null || this.player.isImmobile() || rootVehicle.isRemoved()) { // ensuring awaitingPositionFromClient is null
                return;
            }
            // Paper end - Don't allow vehicle movement from players while teleporting
...

as you can see we are ensuring awaitingPositionFromClient is null, but it was already just checked inside this.updateAwaitingTeleport(), which will only return false if awaitingPositionFromClient is null

private boolean updateAwaitingTeleport() {
       if (this.awaitingPositionFromClient != null) {
           if (false && this.tickCount - this.awaitingTeleportTime > 20) { // Paper - this will greatly screw with clients with > 1000ms RTT
               this.awaitingTeleportTime = this.tickCount;
               this.teleport(
                   this.awaitingPositionFromClient.x,
                   this.awaitingPositionFromClient.y,
                   this.awaitingPositionFromClient.z,
                   this.player.getYRot(),
                   this.player.getXRot()
               );
           }
           this.allowedPlayerTicks = 20; // CraftBukkit

           return true;
       } else {
           this.awaitingTeleportTime = this.tickCount;
           return false; // returns false here, right after this.awaitingPositionFromClient == null
       }
   }

...
//ServerGamePacketListenerImpl.handleMoveVehicle()
} else if (!this.updateAwaitingTeleport() && this.player.hasClientLoaded()) { // needs to return false in order to proceed
            Entity rootVehicle = this.player.getRootVehicle();
...

Paper version

daddcf67420e92ce1eba27949f3c847a92ffab14

Start at paper-server/patches/sources/net/minecraft/server/network/ServerGamePacketListenerImpl.java.patch and the handleMoveVehicle() and updateAwaitingTeleport() entry points shown in the issue. Confirm the control flow around awaitingPositionFromClient, then verify the redundant check is gone and the project’s relevant checks pass.