fix(ping): support Purpur NameAndId samples

design/log.md

@@ -2,6 +2,7 @@
 
 ## 2026-09-05
 
+- **Fix**: Reworked US-002 server-list filtering for Purpur's native `NameAndId` samples by filtering names through Bukkit, limiting ProtocolLib to guarded count adjustment, and rate-limiting compatibility warnings; verified the complete Gradle build and OKF bundle.
 - **Completion**: Extended US-002, US-004, and US-005 with a persistent, permission-gated sleep-count policy that excludes concealed players by default, applies immediately, restores prior player state, and supports contextual administration; verified the complete Gradle build and OKF bundle.
 - **Completion**: Extended US-002 with ProtocolLib filtering of concealed sessions from multiplayer server-list counts and player samples while preserving actual online state and advertised capacity; verified the complete Gradle build and OKF bundle.
 

design/user-stories/us-002-rejoin-without-visible-identity.md

@@ -23,6 +23,8 @@ As an **unlocked player**, I want to disconnect while invisibility from a potion
 - [x] Concealed players are excluded from any player-name sample shown for the server-list count, while ordinary players remain represented.
 - [x] The public count never becomes negative, and the configured maximum-player count remains unchanged.
 - [x] Server-list concealment changes only the public ping response and does not alter actual online-player state or gameplay.
+- [x] Server-list filtering remains error-free when Purpur represents player samples with native `NameAndId` values rather than Mojang `GameProfile` values.
+- [x] A server-ping compatibility failure leaves the original response usable and does not produce repeated unhandled listener exceptions.
 - [x] By default, concealed players are excluded from sleep-percentage calculations.
 - [x] When the sleep-count policy is `include`, concealed players count normally; ordinary players are never modified by either policy.
 - [x] A player's previous sleeping-ignore state is restored when concealment ends, the player disconnects or is reset, the policy changes to `include`, or the plugin disables.
@@ -37,7 +39,7 @@ As an **unlocked player**, I want to disconnect while invisibility from a potion
 
 ## Validation
 
-Automated tests verify unlocked and locked disconnect transitions, ordinary-disconnect clearing, one-login consumption, concealed join and quit announcement suppression, preservation of ordinary announcements, private activation messaging, ordinary-login presentation, tab removal for existing and new observers, overhead-name suppression, active concealed-session tracking, public server-list count and sample filtering, nonnegative counts, unchanged maximum capacity, default sleep-count exclusion, immediate policy changes, restoration of prior sleeping-ignore state, and the absence of entity-hiding calls. ProtocolLib is declared as a required dependency, prepared state round trips through YAML, and `./gradlew clean check jar` passes.
+Automated tests verify unlocked and locked disconnect transitions, ordinary-disconnect clearing, one-login consumption, concealed join and quit announcement suppression, preservation of ordinary announcements, private activation messaging, ordinary-login presentation, tab removal for existing and new observers, overhead-name suppression, active concealed-session tracking, ProtocolLib-independent native player-sample filtering, guarded public server-list count adjustment, nonnegative counts, unchanged maximum capacity, default sleep-count exclusion, immediate policy changes, restoration of prior sleeping-ignore state, and the absence of entity-hiding calls. ProtocolLib is declared as a required dependency, prepared state round trips through YAML, and `./gradlew clean check jar` passes.
 
 ## Related
 

src/main/java/games/dmg/spigotstealth/ProtocolLibServerListPingListener.java

@@ -3,42 +3,35 @@ package games.dmg.spigotstealth;
 import com.comphenix.protocol.PacketType;
 import com.comphenix.protocol.events.PacketAdapter;
 import com.comphenix.protocol.events.PacketEvent;
-import com.comphenix.protocol.wrappers.WrappedGameProfile;
 import com.comphenix.protocol.wrappers.WrappedServerPing;
-import java.util.List;
 import java.util.Objects;
 import java.util.Set;
 import java.util.UUID;
+import java.util.function.Consumer;
 import java.util.function.Supplier;
 import org.bukkit.plugin.Plugin;
 
-/** Rewrites outgoing server-list responses without changing actual online-player state. */
+/** Adjusts only the count in outgoing server-list responses through ProtocolLib. */
 public final class ProtocolLibServerListPingListener extends PacketAdapter {
     private final Supplier<Set<UUID>> concealedPlayerIds;
+    private final ServerPingCompatibilityGuard compatibilityGuard;
 
-    public ProtocolLibServerListPingListener(Plugin plugin, Supplier<Set<UUID>> concealedPlayerIds) {
+    public ProtocolLibServerListPingListener(
+            Plugin plugin,
+            Supplier<Set<UUID>> concealedPlayerIds,
+            Consumer<String> warningLog) {
         super(plugin, PacketType.Status.Server.SERVER_INFO);
         this.concealedPlayerIds = Objects.requireNonNull(concealedPlayerIds, "concealedPlayerIds");
+        this.compatibilityGuard = new ServerPingCompatibilityGuard(warningLog);
     }
 
     @Override
     public void onPacketSending(PacketEvent event) {
-        WrappedServerPing visiblePing = event.getPacket().getServerPings().read(0).deepClone();
-        boolean sampleVisible = visiblePing.isPlayersVisible();
-        List<WrappedGameProfile> sample = sampleVisible ? visiblePing.getPlayers() : List.of();
-        Set<UUID> concealed = concealedPlayerIds.get();
-        ServerListPingVisibility.Snapshot visible = ServerListPingVisibility.adjust(
-                visiblePing.getPlayersOnline(),
-                visiblePing.getPlayersMaximum(),
-                sample.stream().map(WrappedGameProfile::getUUID).toList(),
-                concealed);
-        Set<UUID> visibleSampleIds = Set.copyOf(visible.samplePlayerIds());
-        visiblePing.setPlayersOnline(visible.playersOnline());
-        if (sampleVisible) {
-            visiblePing.setPlayers(sample.stream()
-                    .filter(profile -> visibleSampleIds.contains(profile.getUUID()))
-                    .toList());
-        }
-        event.getPacket().getServerPings().write(0, visiblePing);
+        compatibilityGuard.run(() -> {
+            WrappedServerPing ping = event.getPacket().getServerPings().read(0);
+            int visiblePlayers = ServerListPingVisibility.visibleOnlineCount(
+                    ping.getPlayersOnline(), concealedPlayerIds.get().size());
+            ping.setPlayersOnline(visiblePlayers);
+        });
     }
 }

src/main/java/games/dmg/spigotstealth/ServerListPingListener.java

@@ -0,0 +1,32 @@
+package games.dmg.spigotstealth;
+
+import java.util.Iterator;
+import java.util.Objects;
+import java.util.Set;
+import java.util.UUID;
+import java.util.function.Supplier;
+import org.bukkit.entity.Player;
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.EventPriority;
+import org.bukkit.event.Listener;
+import org.bukkit.event.server.ServerListPingEvent;
+
+/** Filters concealed players through Bukkit's native server-list sample representation. */
+public final class ServerListPingListener implements Listener {
+    private final Supplier<Set<UUID>> concealedPlayerIds;
+
+    public ServerListPingListener(Supplier<Set<UUID>> concealedPlayerIds) {
+        this.concealedPlayerIds = Objects.requireNonNull(concealedPlayerIds, "concealedPlayerIds");
+    }
+
+    @EventHandler(priority = EventPriority.HIGHEST)
+    public void onServerListPing(ServerListPingEvent event) {
+        Set<UUID> concealed = concealedPlayerIds.get();
+        Iterator<Player> sample = event.iterator();
+        while (sample.hasNext()) {
+            if (concealed.contains(sample.next().getUniqueId())) {
+                sample.remove();
+            }
+        }
+    }
+}

src/main/java/games/dmg/spigotstealth/ServerListPingVisibility.java

@@ -20,11 +20,15 @@ public final class ServerListPingVisibility {
                 .filter(playerId -> !concealedPlayerIds.contains(playerId))
                 .toList();
         return new Snapshot(
-                Math.max(0, playersOnline - concealedPlayerIds.size()),
+                visibleOnlineCount(playersOnline, concealedPlayerIds.size()),
                 playersMaximum,
                 visibleSample);
     }
 
+    public static int visibleOnlineCount(int playersOnline, int concealedPlayers) {
+        return Math.max(0, playersOnline - concealedPlayers);
+    }
+
     public record Snapshot(int playersOnline, int playersMaximum, List<UUID> samplePlayerIds) {
         public Snapshot {
             samplePlayerIds = List.copyOf(samplePlayerIds);

src/main/java/games/dmg/spigotstealth/ServerPingCompatibilityGuard.java

@@ -0,0 +1,26 @@
+package games.dmg.spigotstealth;
+
+import java.util.Objects;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.function.Consumer;
+
+/** Keeps an incompatible server-ping adapter from breaking responses or flooding logs. */
+public final class ServerPingCompatibilityGuard {
+    private final Consumer<String> warningLog;
+    private final AtomicBoolean warningLogged = new AtomicBoolean();
+
+    public ServerPingCompatibilityGuard(Consumer<String> warningLog) {
+        this.warningLog = Objects.requireNonNull(warningLog, "warningLog");
+    }
+
+    public void run(Runnable edit) {
+        try {
+            edit.run();
+        } catch (RuntimeException exception) {
+            if (warningLogged.compareAndSet(false, true)) {
+                warningLog.accept("Unable to adjust the public server-list player count; "
+                        + "the original response will be used: " + exception.getMessage());
+            }
+        }
+    }
+}

src/main/java/games/dmg/spigotstealth/SpigotStealthPlugin.java

@@ -82,8 +82,10 @@ public final class SpigotStealthPlugin extends JavaPlugin {
                 Objects.requireNonNull(getServer().getScoreboardManager(), "scoreboard manager").getMainScoreboard(),
                 new ProtocolLibTabListController(protocolManager),
                 () -> manager.snapshot().sleepCountPolicy());
-        protocolManager.addPacketListener(
-                new ProtocolLibServerListPingListener(this, sessions::concealedPlayerIds));
+        protocolManager.addPacketListener(new ProtocolLibServerListPingListener(
+                this, sessions::concealedPlayerIds, getLogger()::warning));
+        getServer().getPluginManager().registerEvents(
+                new ServerListPingListener(sessions::concealedPlayerIds), this);
         getServer().getPluginManager().registerEvents(
                 new InvisibilityEffectListener(progression, Clock.systemUTC()), this);
         getServer().getPluginManager().registerEvents(

src/test/java/games/dmg/spigotstealth/ServerListPingListenerTest.java

@@ -0,0 +1,36 @@
+package games.dmg.spigotstealth;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Set;
+import java.util.UUID;
+import org.bukkit.entity.Player;
+import org.bukkit.event.server.ServerListPingEvent;
+import org.junit.jupiter.api.Test;
+
+class ServerListPingListenerTest {
+    @Test
+    void removesOnlyConcealedPlayersFromNativeServerPingSample() {
+        UUID concealedId = UUID.randomUUID();
+        Player visible = player(UUID.randomUUID());
+        Player concealed = player(concealedId);
+        ArrayList<Player> sample = new ArrayList<>(List.of(visible, concealed));
+        ServerListPingEvent event = mock(ServerListPingEvent.class);
+        when(event.iterator()).thenReturn(sample.iterator());
+        ServerListPingListener listener = new ServerListPingListener(() -> Set.of(concealedId));
+
+        listener.onServerListPing(event);
+
+        assertEquals(List.of(visible), sample);
+    }
+
+    private static Player player(UUID playerId) {
+        Player player = mock(Player.class);
+        when(player.getUniqueId()).thenReturn(playerId);
+        return player;
+    }
+}

src/test/java/games/dmg/spigotstealth/ServerPingCompatibilityGuardTest.java

@@ -0,0 +1,24 @@
+package games.dmg.spigotstealth;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+
+import java.util.ArrayList;
+import org.junit.jupiter.api.Test;
+
+class ServerPingCompatibilityGuardTest {
+    @Test
+    void compatibilityFailureLeavesPingHandlingUsableAndWarnsOnlyOnce() {
+        ArrayList<String> warnings = new ArrayList<>();
+        ServerPingCompatibilityGuard guard = new ServerPingCompatibilityGuard(warnings::add);
+
+        assertDoesNotThrow(() -> guard.run(() -> {
+            throw new IllegalArgumentException("unsupported profile representation");
+        }));
+        assertDoesNotThrow(() -> guard.run(() -> {
+            throw new IllegalArgumentException("unsupported profile representation");
+        }));
+
+        assertEquals(1, warnings.size());
+    }
+}