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Fix setVelocity infinite regress crash #16

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Fix setVelocity infinite regress crash #16

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20 changes: 19 additions & 1 deletion bukkit/src/main/java/me/caseload/knockbacksync/player/BukkitPlayer.java
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Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,7 @@
import com.google.common.base.Preconditions;
import me.caseload.knockbacksync.BukkitBase;
import me.caseload.knockbacksync.Platform;
import me.caseload.knockbacksync.manager.PlayerDataManager;
import me.caseload.knockbacksync.world.FoliaWorld;
import me.caseload.knockbacksync.world.PlatformWorld;
import me.caseload.knockbacksync.world.SpigotWorld;
Expand Down Expand Up @@ -190,7 +191,24 @@ public int getMainHandKnockbackLevel() {

@Override
public void setVelocity(Vector3d adjustedVelocity) {
bukkitPlayer.setVelocity(new Vector(adjustedVelocity.x, adjustedVelocity.y, adjustedVelocity.z));
PlayerData data = PlayerDataManager.getPlayerData(this.getUser());

if(data == null){
// Fallback to normal behavior in the absence of a guard
bukkitPlayer.setVelocity(new Vector(adjustedVelocity.x, adjustedVelocity.y, adjustedVelocity.z));
return;
}

if(data.isVelocityGuard()){
return; // Already applying velocity
}

data.setVelocityGuard(true);
try {
this.bukkitPlayer.setVelocity(new Vector(adjustedVelocity.x, adjustedVelocity.y, adjustedVelocity.z));
} finally {
data.setVelocityGuard(false);
}
}

@Override
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5 changes: 5 additions & 0 deletions common/src/main/java/me/caseload/knockbacksync/listener/PlayerKnockbackListener.java
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Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,9 @@ public void onPlayerVelocity(PlatformPlayer victim, Vector3d velocity) {
PlayerData victimPlayerData = PlayerDataManager.getPlayerData(user);
if (victimPlayerData == null)
return;
if (victimPlayerData.isVelocityGuard()) { // Prevent velocity setter from looping infinitely
return;
}

if (victimPlayerData.getNotNullPing() < PlayerData.PING_OFFSET)
return;
Expand Down Expand Up @@ -50,6 +53,8 @@ else if (victimPlayerData.isOffGroundSyncEnabled())
else
return;

victimPlayerData.setVelocityGuard(true);;
victim.setVelocity(adjustedVelocity);
victimPlayerData.setVelocityGuard(false);
}
}
2 changes: 2 additions & 0 deletions common/src/main/java/me/caseload/knockbacksync/player/PlayerData.java
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Original file line number Diff line number Diff line change
Expand Up @@ -47,6 +47,8 @@ public class PlayerData {
public static final long PING_OFFSET = 25;

private static Field playerField;
@Getter @Setter
private boolean velocityGuard = false; // Used to prevent infinite recursion while setting velocity

public final Queue<Pair<Integer, Long>> transactionsSent = new ConcurrentLinkedQueue<>();
public final Queue<Pair<Long, Long>> keepaliveMap = new ConcurrentLinkedQueue<>();
Expand Down