feat(stealth): earn and equip the Eye of True Seeing

Add independent eight-hour Night Vision progression, save-gated crafting and holder eligibility, authenticated helmet items and guarded inventory movement. Verify source attribution, native item/recipe/event adapters and actual plugin lifecycle. Drain final state asynchronously and reject stale lifecycle callbacks. Per-viewer revelation remains the next story; no deployment is included.

src/nativeTest/java/games/dmg/spigotstealth/EyeCraftingTest.java

@@ -0,0 +1,215 @@
+package games.dmg.spigotstealth;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.Mockito.*;
+
+import java.nio.file.Path;
+import java.util.UUID;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicReference;
+import org.bukkit.Material;
+import org.bukkit.entity.Player;
+import org.bukkit.event.inventory.PrepareItemCraftEvent;
+import org.bukkit.inventory.CraftingInventory;
+import org.bukkit.inventory.InventoryView;
+import org.bukkit.inventory.ItemStack;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+class EyeCraftingTest {
+    @TempDir Path directory;
+    @BeforeAll static void bootstrap() throws Exception { NativeRuntime.bootstrap(); }
+
+    @Test
+    void eightNetheriteBlocksAroundAnEnderEyeCanOnlyBeCraftedAfterThePersonalUnlock() throws Exception {
+        var repository = new YamlStealthStateRepository(directory.resolve("state.yml"));
+        UUID id = UUID.randomUUID();
+        try (var states = new StealthStateManager(repository, repository.load())) {
+            var progression = new EyeProgressionService(states, () -> 0L, ignored -> { });
+            var items = new EyeItems();
+            var crafting = new EyeCrafting(progression, items);
+            var recipe = crafting.recipe();
+            assertArrayEquals(new String[] {"NNN", "NEN", "NNN"}, recipe.getShape());
+            assertEquals(Material.NETHERITE_BLOCK, recipe.getIngredientMap().get('N').getType());
+            assertEquals(Material.ENDER_EYE, recipe.getIngredientMap().get('E').getType());
+            assertTrue(items.isEye(recipe.getResult()));
+            var player = mock(Player.class);
+            when(player.getUniqueId()).thenReturn(id);
+            var inventory = mock(CraftingInventory.class);
+            when(inventory.getRecipe()).thenReturn(recipe);
+            when(inventory.getMatrix()).thenReturn(matrix());
+            var result = new AtomicReference<>(recipe.getResult());
+            when(inventory.getResult()).thenAnswer(ignored -> result.get());
+            doAnswer(call -> { result.set(call.getArgument(0)); return null; }).when(inventory).setResult(any());
+            var view = mock(InventoryView.class);
+            when(view.getPlayer()).thenReturn(player);
+            when(view.getTopInventory()).thenReturn(inventory);
+            var event = new PrepareItemCraftEvent(inventory, view, false);
+            crafting.onPrepare(event);
+            assertNull(result.get(), "a locked player cannot obtain the recipe result");
+            states.update(state -> state.withEyeProgress(id, new EyeProgress(28_800_000, true))).get(3, TimeUnit.SECONDS);
+            result.set(recipe.getResult()); // A fresh native recipe preparation after earning the unlock.
+            crafting.onPrepare(event);
+            assertTrue(items.isEye(result.get()));
+            assertEquals(1, result.get().getAmount());
+            verify(inventory, never()).setMatrix(any()); // Vanilla owns all ingredient consumption.
+        }
+    }
+
+    @Test
+    void resultClicksRecheckEligibilityIngredientsAndIdentityWithoutBypassingCancellation() throws Exception {
+        var repository = new YamlStealthStateRepository(directory.resolve("state.yml"));
+        UUID id = UUID.randomUUID();
+        try (var states = new StealthStateManager(repository, repository.load())) {
+            var progression = new EyeProgressionService(states, () -> 0L, ignored -> { });
+            var items = new EyeItems();
+            var crafting = new EyeCrafting(progression, items);
+            var recipe = crafting.recipe();
+            var player = mock(Player.class);
+            when(player.getUniqueId()).thenReturn(id);
+            var inventory = mock(CraftingInventory.class);
+            when(inventory.getRecipe()).thenReturn(recipe);
+            ItemStack[] ingredients = matrix();
+            when(inventory.getMatrix()).thenReturn(ingredients);
+            var result = new AtomicReference<>(recipe.getResult());
+            when(inventory.getResult()).thenAnswer(ignored -> result.get());
+            doAnswer(call -> { result.set(call.getArgument(0)); return null; }).when(inventory).setResult(any());
+            var view = mock(InventoryView.class);
+            when(view.getPlayer()).thenReturn(player);
+            when(view.getTopInventory()).thenReturn(inventory);
+            var locked = click(recipe, view);
+            crafting.onCraft(locked);
+            assertTrue(locked.isCancelled(), "a stale preview must not bypass the personal unlock on shift-click");
+            assertNull(result.get());
+            states.update(state -> state.withEyeProgress(id, new EyeProgress(28_800_000, true))).get(3, TimeUnit.SECONDS);
+            result.set(recipe.getResult());
+            var allowed = click(recipe, view);
+            crafting.onCraft(allowed);
+            assertFalse(allowed.isCancelled());
+            assertTrue(items.isEye(result.get()));
+            ingredients[0] = new ItemStack(Material.DIRT);
+            var invalidIngredients = click(recipe, view);
+            crafting.onCraft(invalidIngredients);
+            assertTrue(invalidIngredients.isCancelled());
+            assertNull(result.get());
+            ingredients[0] = new ItemStack(Material.NETHERITE_BLOCK);
+            result.set(new ItemStack(Material.ENDER_EYE));
+            var invalidResult = click(recipe, view);
+            crafting.onCraft(invalidResult);
+            assertTrue(invalidResult.isCancelled());
+            result.set(recipe.getResult());
+            result.get().setAmount(2);
+            var inflatedResult = click(recipe, view);
+            crafting.onCraft(inflatedResult);
+            assertTrue(inflatedResult.isCancelled());
+            result.set(recipe.getResult());
+            var cancelled = click(recipe, view);
+            cancelled.setCancelled(true);
+            crafting.onCraft(cancelled);
+            assertTrue(cancelled.isCancelled());
+            var otherRecipe = new org.bukkit.inventory.ShapedRecipe(new org.bukkit.NamespacedKey("other", "eye"),
+                    new ItemStack(Material.ENDER_EYE)).shape("E").setIngredient('E', Material.ENDER_EYE);
+            var unrelated = click(otherRecipe, view);
+            crafting.onCraft(unrelated);
+            assertFalse(unrelated.isCancelled());
+            verify(inventory, never()).setMatrix(any());
+        }
+    }
+
+    @Test
+    void pendingOrFailedUnlockWritesCannotExposeACraftableResult() throws Exception {
+        var disk = new YamlStealthStateRepository(directory.resolve("state.yml"));
+        var started = new java.util.concurrent.CountDownLatch(1);
+        var release = new java.util.concurrent.CountDownLatch(1);
+        var firstWrite = new java.util.concurrent.atomic.AtomicBoolean(true);
+        StealthStateRepository repository = new StealthStateRepository() {
+            @Override public PersistentStealthState load() throws java.io.IOException { return disk.load(); }
+            @Override public void save(PersistentStealthState state) throws java.io.IOException {
+                if (firstWrite.getAndSet(false)) {
+                    started.countDown();
+                    try {
+                        if (!release.await(3, TimeUnit.SECONDS)) { throw new java.io.IOException("Test write gate timed out"); }
+                    } catch (InterruptedException exception) {
+                        Thread.currentThread().interrupt();
+                        throw new java.io.IOException(exception);
+                    }
+                    throw new java.io.IOException("Injected write failure");
+                }
+                disk.save(state);
+            }
+        };
+        UUID id = UUID.randomUUID();
+        try (var states = new StealthStateManager(repository, repository.load())) {
+            try {
+                var items = new EyeItems();
+                var crafting = new EyeCrafting(new EyeProgressionService(states, () -> 0L, ignored -> { }), items);
+                var recipe = crafting.recipe();
+                var player = mock(Player.class);
+                when(player.getUniqueId()).thenReturn(id);
+                var inventory = mock(CraftingInventory.class);
+                when(inventory.getRecipe()).thenReturn(recipe);
+                when(inventory.getMatrix()).thenReturn(matrix());
+                var result = new AtomicReference<>(recipe.getResult());
+                when(inventory.getResult()).thenAnswer(ignored -> result.get());
+                doAnswer(call -> { result.set(call.getArgument(0)); return null; }).when(inventory).setResult(any());
+                var view = mock(InventoryView.class);
+                when(view.getPlayer()).thenReturn(player);
+                when(view.getTopInventory()).thenReturn(inventory);
+                var event = new PrepareItemCraftEvent(inventory, view, false);
+                var pending = states.update(state -> state.withEyeProgress(id, new EyeProgress(28_800_000, true)));
+                assertTrue(started.await(3, TimeUnit.SECONDS));
+                assertTrue(states.snapshot().eyeProgress(id).unlocked());
+                crafting.onPrepare(event);
+                assertNull(result.get(), "in-memory progress is not a durable crafting unlock");
+                release.countDown();
+                assertThrows(java.util.concurrent.ExecutionException.class, () -> pending.get(3, TimeUnit.SECONDS));
+                result.set(recipe.getResult());
+                crafting.onPrepare(event);
+                assertNull(result.get(), "failed writes must not grant the recipe");
+                var denied = click(recipe, view);
+                crafting.onCraft(denied);
+                assertTrue(denied.isCancelled());
+                states.save().get(3, TimeUnit.SECONDS);
+                result.set(recipe.getResult());
+                crafting.onPrepare(event);
+                assertTrue(items.isEye(result.get()));
+                var allowed = click(recipe, view);
+                crafting.onCraft(allowed);
+                assertFalse(allowed.isCancelled());
+            } finally { release.countDown(); }
+        }
+    }
+
+    @Test
+    void automatedCraftersCannotBypassPersonalProgression() throws Exception {
+        var repository = new YamlStealthStateRepository(directory.resolve("state.yml"));
+        try (var states = new StealthStateManager(repository, repository.load())) {
+            var items = new EyeItems();
+            var crafting = new EyeCrafting(new EyeProgressionService(states, () -> 0L, ignored -> { }), items);
+            var block = mock(org.bukkit.block.Block.class);
+            var event = new org.bukkit.event.block.CrafterCraftEvent(block, crafting.recipe(), items.create());
+            crafting.onCrafter(event);
+            assertTrue(event.isCancelled(), "a block has no personal Eye unlock");
+            var other = new org.bukkit.inventory.ShapedRecipe(new org.bukkit.NamespacedKey("other", "eye"),
+                    new ItemStack(Material.ENDER_EYE)).shape("E").setIngredient('E', Material.ENDER_EYE);
+            var unrelated = new org.bukkit.event.block.CrafterCraftEvent(block, other, other.getResult());
+            crafting.onCrafter(unrelated);
+            assertFalse(unrelated.isCancelled());
+        }
+    }
+
+    private static org.bukkit.event.inventory.CraftItemEvent click(org.bukkit.inventory.Recipe recipe, InventoryView view) {
+        return new org.bukkit.event.inventory.CraftItemEvent(recipe, view,
+                org.bukkit.event.inventory.InventoryType.SlotType.RESULT, 0,
+                org.bukkit.event.inventory.ClickType.SHIFT_LEFT, org.bukkit.event.inventory.InventoryAction.MOVE_TO_OTHER_INVENTORY);
+    }
+
+    private static ItemStack[] matrix() {
+        var result = new ItemStack[9];
+        for (int index = 0; index < result.length; index++) {
+            result[index] = new ItemStack(index == 4 ? Material.ENDER_EYE : Material.NETHERITE_BLOCK);
+        }
+        return result;
+    }
+}

src/nativeTest/java/games/dmg/spigotstealth/EyeEquipmentTest.java

@@ -0,0 +1,92 @@
+package games.dmg.spigotstealth;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.Mockito.*;
+
+import java.nio.file.Path;
+import java.util.EnumMap;
+import java.util.UUID;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicReference;
+import org.bukkit.Material;
+import org.bukkit.block.BlockFace;
+import org.bukkit.entity.Player;
+import org.bukkit.event.Event;
+import org.bukkit.event.block.Action;
+import org.bukkit.event.player.PlayerInteractEvent;
+import org.bukkit.inventory.EquipmentSlot;
+import org.bukkit.inventory.ItemStack;
+import org.bukkit.inventory.PlayerInventory;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+class EyeEquipmentTest {
+    @TempDir Path directory;
+    @BeforeAll static void bootstrap() throws Exception { NativeRuntime.bootstrap(); }
+
+    @Test
+    void tradedEyesRequireTheHoldersOwnUnlockAndEquipWithoutThrowingOrReplacingAHelmet() throws Exception {
+        UUID earner = UUID.randomUUID(), holder = UUID.randomUUID();
+        var repository = new YamlStealthStateRepository(directory.resolve("state.yml"));
+        try (var states = new StealthStateManager(repository, repository.load())) {
+            states.update(state -> state.withEyeProgress(earner, new EyeProgress(28_800_000, true))).get(3, TimeUnit.SECONDS);
+            var items = new EyeItems();
+            var equipment = new EyeEquipment(new EyeProgressionService(states, () -> 0L, ignored -> { }), items);
+            var player = mock(Player.class);
+            when(player.getUniqueId()).thenReturn(holder);
+            var inventory = mock(PlayerInventory.class);
+            when(player.getInventory()).thenReturn(inventory);
+            var helmet = new AtomicReference<ItemStack>();
+            when(inventory.getHelmet()).thenAnswer(ignored -> helmet.get());
+            doAnswer(call -> { helmet.set(call.getArgument(0)); return null; }).when(inventory).setHelmet(any());
+            var hands = new EnumMap<EquipmentSlot, ItemStack>(EquipmentSlot.class);
+            when(inventory.getItem(any(EquipmentSlot.class))).thenAnswer(call -> hands.get(call.getArgument(0)));
+            doAnswer(call -> { hands.put(call.getArgument(0), call.getArgument(1)); return null; })
+                    .when(inventory).setItem(any(EquipmentSlot.class), nullable(ItemStack.class));
+            ItemStack traded = items.create();
+            hands.put(EquipmentSlot.HAND, traded);
+            helmet.set(traded.clone());
+            assertFalse(equipment.isEligibleWearer(player), "equipping somebody else's Eye must not bypass the personal unlock");
+            helmet.set(null);
+            var denied = use(player, traded, EquipmentSlot.HAND);
+            equipment.onUse(denied);
+            assertEquals(Event.Result.DENY, denied.useItemInHand(), "custom Eyes must never fall through to vanilla Ender Eye use");
+            assertNull(helmet.get());
+            assertSame(traded, hands.get(EquipmentSlot.HAND));
+            states.update(state -> state.withEyeProgress(holder, new EyeProgress(28_800_000, true))).get(3, TimeUnit.SECONDS);
+            var allowed = use(player, traded, EquipmentSlot.HAND);
+            equipment.onUse(allowed);
+            assertEquals(Event.Result.DENY, allowed.useItemInHand());
+            assertNull(hands.get(EquipmentSlot.HAND));
+            assertTrue(items.isEye(helmet.get()));
+            assertEquals(1, helmet.get().getAmount());
+            assertTrue(equipment.isEligibleWearer(player));
+            var ordinaryHelmet = new ItemStack(Material.IRON_HELMET);
+            helmet.set(ordinaryHelmet);
+            hands.put(EquipmentSlot.OFF_HAND, items.create());
+            equipment.onUse(use(player, hands.get(EquipmentSlot.OFF_HAND), EquipmentSlot.OFF_HAND));
+            assertSame(ordinaryHelmet, helmet.get());
+            assertTrue(items.isEye(hands.get(EquipmentSlot.OFF_HAND)));
+            assertFalse(equipment.isEligibleWearer(player), "holding an Eye is not wearing it");
+            helmet.set(null);
+            equipment.onUse(use(player, hands.get(EquipmentSlot.OFF_HAND), EquipmentSlot.OFF_HAND));
+            assertNull(hands.get(EquipmentSlot.OFF_HAND));
+            assertTrue(equipment.isEligibleWearer(player));
+            helmet.set(null);
+            hands.put(EquipmentSlot.HAND, items.create());
+            var cancelled = use(player, hands.get(EquipmentSlot.HAND), EquipmentSlot.HAND);
+            cancelled.setUseItemInHand(Event.Result.DENY);
+            equipment.onUse(cancelled);
+            assertNull(helmet.get());
+            assertTrue(items.isEye(hands.get(EquipmentSlot.HAND)));
+            var ordinary = use(player, new ItemStack(Material.ENDER_EYE), EquipmentSlot.HAND);
+            equipment.onUse(ordinary);
+            assertEquals(Event.Result.DEFAULT, ordinary.useItemInHand());
+        }
+    }
+
+    private static PlayerInteractEvent use(Player player, ItemStack item, EquipmentSlot hand) {
+        return new PlayerInteractEvent(player, Action.RIGHT_CLICK_AIR, item, null, BlockFace.SELF, hand);
+    }
+}

src/nativeTest/java/games/dmg/spigotstealth/EyeItemsTest.java

@@ -0,0 +1,39 @@
+package games.dmg.spigotstealth;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import net.kyori.adventure.text.Component;
+import org.bukkit.Material;
+import org.bukkit.inventory.EquipmentSlot;
+import org.bukkit.inventory.ItemStack;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+
+class EyeItemsTest {
+    @BeforeAll static void bootstrap() throws Exception { NativeRuntime.bootstrap(); }
+
+    @Test
+    void createdEyeIsAnAuthenticatedHelmetItemButPlainAndRenamedEyesAreNot() {
+        var items = new EyeItems();
+        ItemStack eye = items.create();
+        assertEquals(Material.ENDER_EYE, eye.getType());
+        assertEquals(Component.text("Eye of True Seeing"), eye.getItemMeta().displayName());
+        assertTrue(items.isEye(eye));
+        assertTrue(items.isEye(eye.clone()), "ordinary inventory transfer must retain item identity");
+        assertEquals(EquipmentSlot.HEAD, eye.getItemMeta().getEquippable().getSlot());
+        assertEquals(1, eye.getMaxStackSize());
+        assertFalse(eye.getItemMeta().getEquippable().isDispensable());
+        assertFalse(eye.getItemMeta().getEquippable().isEquipOnInteract(),
+                "the eligibility-checked interaction handler, not native item use, equips the Eye");
+        var ordinary = new ItemStack(Material.ENDER_EYE);
+        assertFalse(items.isEye(ordinary));
+        var renamed = ordinary.getItemMeta();
+        renamed.displayName(eye.getItemMeta().displayName());
+        ordinary.setItemMeta(renamed);
+        assertFalse(items.isEye(ordinary), "anvil/display names cannot authenticate an Eye");
+        var wrongMaterial = eye.clone();
+        wrongMaterial.setType(Material.STONE);
+        assertFalse(items.isEye(wrongMaterial));
+        assertFalse(items.isEye(null));
+    }
+}

src/nativeTest/java/games/dmg/spigotstealth/EyePluginLifecycleTest.java

@@ -0,0 +1,216 @@
+package games.dmg.spigotstealth;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.Mockito.*;
+
+import com.comphenix.protocol.ProtocolLibrary;
+import com.comphenix.protocol.ProtocolManager;
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.UUID;
+import java.util.concurrent.LinkedBlockingQueue;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicReference;
+import java.util.function.Consumer;
+import java.util.logging.Logger;
+import org.bukkit.Server;
+import org.bukkit.command.PluginCommand;
+import org.bukkit.configuration.file.YamlConfiguration;
+import org.bukkit.entity.Player;
+import org.bukkit.event.Event;
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.Listener;
+import org.bukkit.event.inventory.PrepareItemCraftEvent;
+import org.bukkit.inventory.CraftingInventory;
+import org.bukkit.inventory.InventoryView;
+import org.bukkit.inventory.ItemStack;
+import org.bukkit.inventory.Recipe;
+import org.bukkit.plugin.EventExecutor;
+import org.bukkit.plugin.PluginDescriptionFile;
+import org.bukkit.plugin.PluginManager;
+import org.bukkit.plugin.RegisteredListener;
+import org.bukkit.scheduler.BukkitScheduler;
+import org.bukkit.scheduler.BukkitTask;
+import org.bukkit.scoreboard.Scoreboard;
+import org.bukkit.scoreboard.ScoreboardManager;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+class EyePluginLifecycleTest {
+    @TempDir Path directory;
+    @BeforeAll static void bootstrap() throws Exception { NativeRuntime.bootstrap(); }
+
+    @org.junit.jupiter.params.ParameterizedTest
+    @org.junit.jupiter.params.provider.ValueSource(strings = {"normal", "disabled", "reenabled", "presentation-failure"})
+    @SuppressWarnings("try") // The scoped Bukkit boundary delegates non-server-metadata operations to native code.
+    void startupAndLateCallbacksRespectSavedUnlocksAndDisable(String mode) throws Exception {
+        UUID id = UUID.randomUUID(), learner = UUID.randomUUID();
+        var disk = new YamlStealthStateRepository(directory.resolve("state.yml"));
+        disk.save(new PersistentStealthState(Map.of(), Map.of()).withEyeProgress(id, new EyeProgress(28_800_000, true)));
+        var plugin = mock(SpigotStealthPlugin.class, CALLS_REAL_METHODS);
+        var clock = new java.util.concurrent.atomic.AtomicLong();
+        doAnswer(ignored -> clock.get()).when(plugin).monotonicNanos();
+        Server server = mock(org.bukkit.craftbukkit.CraftServer.class);
+        var plugins = mock(PluginManager.class);
+        BukkitScheduler scheduler = mock(org.bukkit.craftbukkit.scheduler.CraftScheduler.class);
+        var player = mock(Player.class);
+        when(player.getUniqueId()).thenReturn(id);
+        doReturn(List.of(player)).when(server).getOnlinePlayers();
+        when(server.getPlayer(id)).thenReturn(player);
+        doReturn(server).when(plugin).getServer();
+        doReturn(true).when(plugin).isEnabled();
+        doReturn(directory.toFile()).when(plugin).getDataFolder();
+        doReturn(new YamlConfiguration()).when(plugin).getConfig();
+        doReturn(Logger.getAnonymousLogger()).when(plugin).getLogger();
+        doReturn(new PluginDescriptionFile("SpigotStealth", "test", SpigotStealthPlugin.class.getName()))
+                .when(plugin).getDescription();
+        doNothing().when(plugin).saveDefaultConfig();
+        doReturn(mock(PluginCommand.class)).when(plugin).getCommand("stealth");
+        doReturn(mock(PluginCommand.class)).when(plugin).getCommand("stealthadmin");
+        when(server.getPluginManager()).thenReturn(plugins);
+        when(server.getScheduler()).thenReturn(scheduler);
+        ScoreboardManager boards = mock(org.bukkit.craftbukkit.scoreboard.CraftScoreboardManager.class);
+        when(server.getScoreboardManager()).thenReturn(boards);
+        when(boards.getMainScoreboard()).thenReturn(mock(org.bukkit.craftbukkit.scoreboard.CraftScoreboard.class));
+        var main = new LinkedBlockingQueue<Runnable>();
+        when(scheduler.runTask(eq(plugin), any(Runnable.class))).thenAnswer(call -> {
+            main.add(call.getArgument(1)); return mock(BukkitTask.class);
+        });
+        var timers = new ArrayList<Runnable>();
+        doAnswer(call -> {
+            Consumer<BukkitTask> action = call.getArgument(1);
+            timers.add(() -> action.accept(mock(BukkitTask.class)));
+            return null;
+        }).when(scheduler).runTaskTimer(eq(plugin), org.mockito.ArgumentMatchers.<Consumer<BukkitTask>>any(), anyLong(), anyLong());
+        when(scheduler.runTaskTimer(eq(plugin), any(Runnable.class), anyLong(), anyLong())).thenAnswer(call -> {
+            timers.add(call.getArgument(1)); return mock(BukkitTask.class);
+        });
+        var recipe = new AtomicReference<Recipe>();
+        when(server.addRecipe(any(Recipe.class))).thenAnswer(call -> { recipe.set(call.getArgument(0)); return true; });
+        var listeners = new ArrayList<Listener>();
+        doAnswer(call -> { listeners.add(call.getArgument(0)); return null; }).when(plugins).registerEvents(any(), eq(plugin));
+        try (var platform = mockStatic(org.bukkit.Bukkit.class, call -> switch (call.getMethod().getName()) {
+            case "getServer" -> server;
+            case "getVersion" -> "Purpur 2618 (MC: 26.2)";
+            case "getMinecraftVersion" -> "26.2";
+            case "getBukkitVersion" -> "26.2-R0.1-SNAPSHOT";
+            default -> call.callRealMethod();
+        }); var protocol = mockStatic(ProtocolLibrary.class)) {
+            var protocolManager = mock(ProtocolManager.class);
+            protocol.when(ProtocolLibrary::getProtocolManager).thenReturn(protocolManager);
+            try {
+                plugin.onEnable();
+                assertNull(recipe.get(), "Bukkit registration must wait for durable state initialization and main-thread dispatch");
+                Runnable initialization = main.poll(3, TimeUnit.SECONDS);
+                assertNotNull(initialization);
+                if (mode.equals("disabled") || mode.equals("reenabled")) {
+                    doReturn(false).when(plugin).isEnabled();
+                    plugin.onDisable();
+                    if (mode.equals("reenabled")) {
+                        doReturn(true).when(plugin).isEnabled();
+                        plugin.onEnable();
+                        Runnable currentInitialization = main.poll(3, TimeUnit.SECONDS);
+                        assertNotNull(currentInitialization);
+                        currentInitialization.run();
+                        int registeredCount = listeners.size();
+                        assertNotNull(recipe.get());
+                        initialization.run();
+                        assertEquals(registeredCount, listeners.size(), "an old lifecycle callback must not touch a re-enabled plugin");
+                        verify(server, times(1)).addRecipe(any(Recipe.class));
+                        return;
+                    }
+                    initialization.run();
+                    assertTrue(listeners.isEmpty(), "a queued initialization must not register listeners after disable");
+                    assertNull(recipe.get());
+                    verify(server, never()).removeRecipe(any());
+                    return;
+                }
+                initialization.run();
+                assertNotNull(recipe.get(), "plugin startup must register the Eye recipe");
+                assertTrue(new EyeItems().isEye(recipe.get().getResult()));
+                assertTrue(listeners.stream().anyMatch(EyePotionListener.class::isInstance));
+                assertTrue(listeners.stream().anyMatch(EyeEquipment.class::isInstance));
+                var inventory = mock(CraftingInventory.class);
+                when(inventory.getRecipe()).thenAnswer(ignored -> recipe.get());
+                var result = new AtomicReference<>(recipe.get().getResult());
+                when(inventory.getResult()).thenAnswer(ignored -> result.get());
+                doAnswer(call -> { result.set(call.getArgument(0)); return null; }).when(inventory).setResult(any());
+                var view = mock(InventoryView.class);
+                when(view.getPlayer()).thenReturn(player);
+                when(view.getTopInventory()).thenReturn(inventory);
+                var prepare = new PrepareItemCraftEvent(inventory, view, false);
+                dispatch(plugin, listeners, prepare);
+                assertTrue(new EyeItems().isEye(result.get()), "the restored personal unlock must permit crafting");
+                when(player.getUniqueId()).thenReturn(learner);
+                when(server.getPlayer(learner)).thenReturn(player);
+                dispatch(plugin, listeners, prepare);
+                assertNull(result.get(), "registered handlers must deny an unearned player's result");
+                var effect = new org.bukkit.potion.PotionEffect(org.bukkit.potion.PotionEffectType.NIGHT_VISION, 9600, 0);
+                dispatch(plugin, listeners, new org.bukkit.event.entity.EntityPotionEffectEvent(player, null, effect, player,
+                        org.bukkit.event.entity.EntityPotionEffectEvent.Cause.POTION_DRINK,
+                        org.bukkit.event.entity.EntityPotionEffectEvent.Action.ADDED, false));
+                clock.set(java.time.Duration.ofHours(8).toNanos());
+                dispatch(plugin, listeners, new org.bukkit.event.entity.EntityPotionEffectEvent(player, effect, null, null,
+                        org.bukkit.event.entity.EntityPotionEffectEvent.Cause.EXPIRATION,
+                        org.bukkit.event.entity.EntityPotionEffectEvent.Action.REMOVED, false));
+                Runnable unlocked = main.poll(3, TimeUnit.SECONDS);
+                assertNotNull(unlocked, "the registered potion listener must persist the unlock and schedule its notification");
+                assertTrue(disk.load().eyeProgress(learner).unlocked());
+                unlocked.run();
+                result.set(recipe.get().getResult());
+                dispatch(plugin, listeners, prepare);
+                assertTrue(new EyeItems().isEye(result.get()), "the registered crafting listener must see the newly saved unlock");
+                clearInvocations(player);
+                when(player.getUniqueId()).thenReturn(id);
+                timers.forEach(Runnable::run);
+                verify(player).discoverRecipe(EyeCrafting.RECIPE_KEY);
+                // Disable must checkpoint and drain an in-flight qualifying interval, not just remove the recipe.
+                when(player.getUniqueId()).thenReturn(learner);
+                when(player.isOnline()).thenReturn(true);
+                when(player.getPotionEffect(org.bukkit.potion.PotionEffectType.NIGHT_VISION)).thenReturn(effect);
+                dispatch(plugin, listeners, new org.bukkit.event.entity.EntityPotionEffectEvent(player, null, effect, player,
+                        org.bukkit.event.entity.EntityPotionEffectEvent.Cause.POTION_DRINK,
+                        org.bukkit.event.entity.EntityPotionEffectEvent.Action.ADDED, false));
+                clock.addAndGet(1_234_000_000L);
+            } finally {
+                if (mode.equals("presentation-failure")) {
+                    doThrow(new IllegalStateException("Injected presentation cleanup failure"))
+                            .when(protocolManager).removePacketListeners(plugin);
+                    try {
+                        assertThrows(IllegalStateException.class, plugin::onDisable);
+                        plugin.shutdownCompletion().get(3, TimeUnit.SECONDS);
+                        assertEquals(28_801_234, disk.load().eyeProgress(learner).accumulatedMillis(),
+                                "presentation cleanup failure must not prevent Eye progress from draining");
+                    } finally {
+                        doNothing().when(protocolManager).removePacketListeners(plugin);
+                        plugin.onDisable();
+                        plugin.shutdownCompletion().get(3, TimeUnit.SECONDS);
+                    }
+                } else {
+                    plugin.onDisable();
+                    plugin.shutdownCompletion().get(3, TimeUnit.SECONDS);
+                }
+            }
+        }
+        verify(server).removeRecipe(EyeCrafting.RECIPE_KEY);
+        assertEquals(28_801_234, disk.load().eyeProgress(learner).accumulatedMillis());
+    }
+
+    private static void dispatch(SpigotStealthPlugin plugin, List<Listener> listeners, Event event) throws Exception {
+        var registered = new ArrayList<RegisteredListener>();
+        for (var listener : listeners) {
+            for (var method : listener.getClass().getMethods()) {
+                var handler = method.getAnnotation(EventHandler.class);
+                if (handler == null || method.getParameterCount() != 1 || !method.getParameterTypes()[0].isInstance(event)) { continue; }
+                registered.add(new RegisteredListener(listener,
+                        EventExecutor.create(method, method.getParameterTypes()[0].asSubclass(Event.class)),
+                        handler.priority(), plugin, handler.ignoreCancelled()));
+            }
+        }
+        registered.sort(java.util.Comparator.comparing(RegisteredListener::getPriority));
+        for (var handler : registered) { handler.callEvent(event); }
+    }
+}

src/nativeTest/java/games/dmg/spigotstealth/EyePotionProgressionTest.java

@@ -0,0 +1,302 @@
+package games.dmg.spigotstealth;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.Mockito.*;
+
+import java.nio.file.Path;
+import java.time.Duration;
+import java.util.UUID;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicLong;
+import org.bukkit.entity.Player;
+import org.bukkit.event.entity.EntityPotionEffectEvent;
+import org.bukkit.potion.PotionEffect;
+import org.bukkit.potion.PotionEffectType;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+/** Real Purpur effect/event objects, real progression/persistence, only player and clock are external doubles. */
+class EyePotionProgressionTest {
+    @TempDir Path directory;
+    @BeforeAll static void bootstrap() throws Exception { NativeRuntime.bootstrap(); }
+
+    @Test
+    void aTransitionBeforeTheNextObservationCannotCreditAnUnattributedRestoredEffect() throws Exception {
+        for (String transition : java.util.List.of("quit", "remove", "refresh")) {
+            UUID id = UUID.randomUUID();
+            var player = mock(Player.class);
+            when(player.getUniqueId()).thenReturn(id);
+            when(player.isOnline()).thenReturn(true);
+            var clock = new AtomicLong();
+            var repository = new YamlStealthStateRepository(directory.resolve(transition + ".yml"));
+            try (var states = new StealthStateManager(repository, repository.load())) {
+                var progression = new EyeProgressionService(states, clock::get, ignored -> { });
+                var listener = new EyePotionListener(progression, failure -> fail(failure));
+                var strong = new PotionEffect(PotionEffectType.NIGHT_VISION, 100, 1);
+                var restored = new PotionEffect(PotionEffectType.NIGHT_VISION, 400, 0);
+                listener.onPotionEffect(new EntityPotionEffectEvent(player, null, strong, player,
+                        EntityPotionEffectEvent.Cause.POTION_DRINK, EntityPotionEffectEvent.Action.ADDED, false));
+                when(player.getPotionEffect(PotionEffectType.NIGHT_VISION)).thenReturn(strong);
+                clock.set(Duration.ofSeconds(1).toNanos());
+                listener.checkpoint(ignored -> player);
+                clock.set(Duration.ofSeconds(3).toNanos());
+                when(player.getPotionEffect(PotionEffectType.NIGHT_VISION)).thenReturn(restored);
+                switch (transition) {
+                    case "quit" -> listener.onQuit(new org.bukkit.event.player.PlayerQuitEvent(
+                            player, net.kyori.adventure.text.Component.empty()));
+                    case "remove" -> listener.onPotionEffect(new EntityPotionEffectEvent(player, restored, null, null,
+                            EntityPotionEffectEvent.Cause.EXPIRATION, EntityPotionEffectEvent.Action.REMOVED, false));
+                    case "refresh" -> listener.onPotionEffect(new EntityPotionEffectEvent(player, restored,
+                            new PotionEffect(PotionEffectType.NIGHT_VISION, 800, 0), player,
+                            EntityPotionEffectEvent.Cause.POTION_DRINK, EntityPotionEffectEvent.Action.CHANGED, true));
+                    default -> throw new AssertionError(transition);
+                }
+                states.save().get(3, TimeUnit.SECONDS);
+                assertEquals(1000, repository.load().eyeProgress(id).accumulatedMillis(), transition);
+            }
+        }
+    }
+
+    @Test
+    void periodicObservationStopsAtUnattributedHiddenEffectRestorationOrMissingPlayer() throws Exception {
+        UUID id = UUID.randomUUID();
+        var player = mock(Player.class);
+        when(player.getUniqueId()).thenReturn(id);
+        when(player.isOnline()).thenReturn(true);
+        var clock = new AtomicLong();
+        var repository = new YamlStealthStateRepository(directory.resolve("state.yml"));
+        try (var states = new StealthStateManager(repository, repository.load())) {
+            var progression = new EyeProgressionService(states, clock::get, ignored -> { });
+            var listener = new EyePotionListener(progression, failure -> fail(failure));
+            var strong = new PotionEffect(PotionEffectType.NIGHT_VISION, 100, 1);
+            listener.onPotionEffect(new EntityPotionEffectEvent(player, null, strong, player,
+                    EntityPotionEffectEvent.Cause.POTION_DRINK, EntityPotionEffectEvent.Action.ADDED, false));
+            when(player.getPotionEffect(PotionEffectType.NIGHT_VISION)).thenReturn(
+                    new PotionEffect(PotionEffectType.NIGHT_VISION, 80, 1));
+            clock.set(Duration.ofSeconds(1).toNanos());
+            listener.checkpoint(ignored -> player);
+            states.save().get(3, TimeUnit.SECONDS);
+            assertEquals(1000, repository.load().eyeProgress(id).accumulatedMillis());
+            // Native hidden-effect promotion need not emit a new potion-source event.
+            when(player.getPotionEffect(PotionEffectType.NIGHT_VISION)).thenReturn(
+                    new PotionEffect(PotionEffectType.NIGHT_VISION, 400, 0));
+            clock.set(Duration.ofSeconds(2).toNanos());
+            listener.checkpoint(ignored -> player);
+            clock.set(Duration.ofHours(12).toNanos());
+            listener.checkpoint(ignored -> player);
+            states.save().get(3, TimeUnit.SECONDS);
+            assertEquals(1000, repository.load().eyeProgress(id).accumulatedMillis(),
+                    "unattributed restored effects must not inherit the drink timer");
+            assertTrue(progression.activePlayerIds().isEmpty());
+            listener.onPotionEffect(new EntityPotionEffectEvent(player, null, strong, player,
+                    EntityPotionEffectEvent.Cause.POTION_DRINK, EntityPotionEffectEvent.Action.ADDED, false));
+            clock.addAndGet(Duration.ofDays(1).toNanos());
+            listener.checkpoint(ignored -> null);
+            states.save().get(3, TimeUnit.SECONDS);
+            assertEquals(1000, repository.load().eyeProgress(id).accumulatedMillis());
+            assertTrue(progression.activePlayerIds().isEmpty());
+        }
+    }
+
+    @Test
+    void disconnectClosesTheIntervalAndRestartDoesNotCountTheOfflineGap() throws Exception {
+        UUID id = UUID.randomUUID();
+        var player = mock(Player.class);
+        when(player.getUniqueId()).thenReturn(id);
+        var clock = new AtomicLong();
+        var repository = new YamlStealthStateRepository(directory.resolve("state.yml"));
+        try (var states = new StealthStateManager(repository, repository.load())) {
+            var progression = new EyeProgressionService(states, clock::get, ignored -> { });
+            var listener = new EyePotionListener(progression, failure -> fail(failure));
+            var effect = new PotionEffect(PotionEffectType.NIGHT_VISION, 200, 0);
+            listener.onPotionEffect(new EntityPotionEffectEvent(player, null, effect, player,
+                    EntityPotionEffectEvent.Cause.POTION_DRINK, EntityPotionEffectEvent.Action.ADDED, false));
+            clock.set(Duration.ofSeconds(1).toNanos());
+            when(player.getPotionEffect(PotionEffectType.NIGHT_VISION)).thenReturn(effect);
+            listener.onQuit(new org.bukkit.event.player.PlayerQuitEvent(player, net.kyori.adventure.text.Component.empty()));
+            clock.addAndGet(Duration.ofDays(7).toNanos());
+            progression.checkpoint(id).get(3, TimeUnit.SECONDS);
+            states.save().get(3, TimeUnit.SECONDS);
+            assertEquals(1000, repository.load().eyeProgress(id).accumulatedMillis(),
+                    "disconnect must close the qualifying interval before offline time passes");
+            assertFalse(progression.isUnlocked(id));
+        }
+        try (var restarted = new StealthStateManager(repository, repository.load())) {
+            var progression = new EyeProgressionService(restarted, clock::get, ignored -> { });
+            assertEquals(1000, restarted.snapshot().eyeProgress(id).accumulatedMillis());
+            assertTrue(progression.activePlayerIds().isEmpty());
+            assertFalse(progression.isUnlocked(id));
+        }
+    }
+
+    @Test
+    void everyNonDrinkSourceIsExcludedAndAnEffectiveExternalReplacementStopsCredit() throws Exception {
+        UUID id = UUID.randomUUID();
+        var player = mock(Player.class);
+        when(player.getUniqueId()).thenReturn(id);
+        var clock = new AtomicLong();
+        var repository = new YamlStealthStateRepository(directory.resolve("state.yml"));
+        try (var states = new StealthStateManager(repository, repository.load())) {
+            var progression = new EyeProgressionService(states, clock::get, ignored -> { });
+            var listener = new EyePotionListener(progression, failure -> fail(failure));
+            var effect = new PotionEffect(PotionEffectType.NIGHT_VISION, 200, 0);
+            for (var cause : EntityPotionEffectEvent.Cause.values()) {
+                if (cause == EntityPotionEffectEvent.Cause.POTION_DRINK) { continue; }
+                listener.onPotionEffect(new EntityPotionEffectEvent(player, null, effect, null,
+                        cause, EntityPotionEffectEvent.Action.ADDED, false));
+                clock.addAndGet(Duration.ofSeconds(1).toNanos());
+                progression.checkpoint(id).get(3, TimeUnit.SECONDS);
+                assertEquals(0, states.snapshot().eyeProgress(id).accumulatedMillis(), cause.toString());
+                listener.onPotionEffect(new EntityPotionEffectEvent(player, effect, null, null,
+                        EntityPotionEffectEvent.Cause.EXPIRATION, EntityPotionEffectEvent.Action.REMOVED, false));
+            }
+            listener.onPotionEffect(new EntityPotionEffectEvent(player, null, effect, player,
+                    EntityPotionEffectEvent.Cause.POTION_DRINK, EntityPotionEffectEvent.Action.ADDED, false));
+            clock.addAndGet(Duration.ofSeconds(1).toNanos());
+            listener.onPotionEffect(new EntityPotionEffectEvent(player, effect,
+                    new PotionEffect(PotionEffectType.NIGHT_VISION, 400, 0), null,
+                    EntityPotionEffectEvent.Cause.PLUGIN, EntityPotionEffectEvent.Action.CHANGED, true));
+            clock.addAndGet(Duration.ofHours(12).toNanos());
+            progression.checkpoint(id).get(3, TimeUnit.SECONDS);
+            states.save().get(3, TimeUnit.SECONDS);
+            assertEquals(1000, repository.load().eyeProgress(id).accumulatedMillis());
+            assertFalse(progression.isUnlocked(id));
+        }
+    }
+
+    @Test
+    void cancelledAndUnrelatedEffectEventsCannotStartOrInterruptCredit() throws Exception {
+        UUID id = UUID.randomUUID();
+        var player = mock(Player.class);
+        when(player.getUniqueId()).thenReturn(id);
+        var clock = new AtomicLong();
+        var repository = new YamlStealthStateRepository(directory.resolve("state.yml"));
+        try (var states = new StealthStateManager(repository, repository.load())) {
+            var progression = new EyeProgressionService(states, clock::get, ignored -> { });
+            var listener = new EyePotionListener(progression, failure -> fail(failure));
+            var effect = new PotionEffect(PotionEffectType.NIGHT_VISION, 200, 0);
+            var cancelled = new EntityPotionEffectEvent(player, null, effect, player,
+                    EntityPotionEffectEvent.Cause.POTION_DRINK, EntityPotionEffectEvent.Action.ADDED, false);
+            cancelled.setCancelled(true);
+            listener.onPotionEffect(cancelled);
+            clock.set(Duration.ofSeconds(1).toNanos());
+            progression.checkpoint(id).get(3, TimeUnit.SECONDS);
+            assertEquals(0, states.snapshot().eyeProgress(id).accumulatedMillis());
+            cancelled.setCancelled(false);
+            listener.onPotionEffect(cancelled);
+            clock.set(Duration.ofSeconds(2).toNanos());
+            var cancelledRemoval = new EntityPotionEffectEvent(player, effect, null, null,
+                    EntityPotionEffectEvent.Cause.MILK, EntityPotionEffectEvent.Action.CLEARED, false);
+            cancelledRemoval.setCancelled(true);
+            listener.onPotionEffect(cancelledRemoval);
+            listener.onPotionEffect(new EntityPotionEffectEvent(player, null,
+                    new PotionEffect(PotionEffectType.INVISIBILITY, 200, 0), null,
+                    EntityPotionEffectEvent.Cause.PLUGIN, EntityPotionEffectEvent.Action.ADDED, false));
+            clock.set(Duration.ofSeconds(3).toNanos());
+            progression.stop(id).get(3, TimeUnit.SECONDS);
+            assertEquals(2000, repository.load().eyeProgress(id).accumulatedMillis());
+        }
+    }
+
+    @Test
+    void cosmeticOnlyOverridesDoNotReassignTheActiveEffectsSource() throws Exception {
+        // Purpur reports override=true even when only particle/icon flags change.
+        var nativeActive = new net.minecraft.world.effect.MobEffectInstance(
+                net.minecraft.world.effect.MobEffects.NIGHT_VISION, 200, 1);
+        assertTrue(nativeActive.update(new net.minecraft.world.effect.MobEffectInstance(
+                net.minecraft.world.effect.MobEffects.NIGHT_VISION, 100, 0, false, false, false)));
+        assertEquals(1, nativeActive.getAmplifier());
+        assertEquals(200, nativeActive.getDuration());
+        UUID id = UUID.randomUUID();
+        var player = mock(Player.class);
+        when(player.getUniqueId()).thenReturn(id);
+        var clock = new AtomicLong();
+        var repository = new YamlStealthStateRepository(directory.resolve("state.yml"));
+        try (var states = new StealthStateManager(repository, repository.load())) {
+            var progression = new EyeProgressionService(states, clock::get, ignored -> { });
+            var listener = new EyePotionListener(progression, failure -> fail(failure));
+            var weak = new PotionEffect(PotionEffectType.NIGHT_VISION, 100, 0, false, false, false);
+            var strong = new PotionEffect(PotionEffectType.NIGHT_VISION, 200, 1);
+            listener.onPotionEffect(new EntityPotionEffectEvent(player, strong, weak, player,
+                    EntityPotionEffectEvent.Cause.POTION_DRINK, EntityPotionEffectEvent.Action.CHANGED, true));
+            clock.set(Duration.ofSeconds(1).toNanos());
+            progression.checkpoint(id).get(3, TimeUnit.SECONDS);
+            assertEquals(0, states.snapshot().eyeProgress(id).accumulatedMillis(),
+                    "a cosmetic drink change must not claim the stronger existing effect");
+            listener.onPotionEffect(new EntityPotionEffectEvent(player, null, strong, player,
+                    EntityPotionEffectEvent.Cause.POTION_DRINK, EntityPotionEffectEvent.Action.ADDED, false));
+            clock.set(Duration.ofSeconds(2).toNanos());
+            listener.onPotionEffect(new EntityPotionEffectEvent(player, strong, weak, null,
+                    EntityPotionEffectEvent.Cause.PLUGIN, EntityPotionEffectEvent.Action.CHANGED, true));
+            clock.set(Duration.ofSeconds(3).toNanos());
+            listener.onPotionEffect(new EntityPotionEffectEvent(player, strong, null, null,
+                    EntityPotionEffectEvent.Cause.EXPIRATION, EntityPotionEffectEvent.Action.REMOVED, false));
+            states.save().get(3, TimeUnit.SECONDS);
+            assertEquals(2000, states.snapshot().eyeProgress(id).accumulatedMillis());
+        }
+    }
+
+    @Test
+    void rejectedReplacementsNeitherStartNorStopQualifyingTime() throws Exception {
+        UUID id = UUID.randomUUID();
+        var player = mock(Player.class);
+        when(player.getUniqueId()).thenReturn(id);
+        var clock = new AtomicLong();
+        var repository = new YamlStealthStateRepository(directory.resolve("state.yml"));
+        try (var states = new StealthStateManager(repository, repository.load())) {
+            var progression = new EyeProgressionService(states, clock::get, ignored -> { });
+            var listener = new EyePotionListener(progression, failure -> fail(failure));
+            var weak = new PotionEffect(PotionEffectType.NIGHT_VISION, 100, 0);
+            var strong = new PotionEffect(PotionEffectType.NIGHT_VISION, 200, 1);
+            listener.onPotionEffect(new EntityPotionEffectEvent(player, strong, weak, player,
+                    EntityPotionEffectEvent.Cause.POTION_DRINK, EntityPotionEffectEvent.Action.CHANGED, false));
+            clock.set(Duration.ofSeconds(1).toNanos());
+            progression.checkpoint(id).get(3, TimeUnit.SECONDS);
+            assertEquals(0, states.snapshot().eyeProgress(id).accumulatedMillis(),
+                    "a rejected drink must not claim an existing non-drink effect");
+            listener.onPotionEffect(new EntityPotionEffectEvent(player, null, strong, player,
+                    EntityPotionEffectEvent.Cause.POTION_DRINK, EntityPotionEffectEvent.Action.ADDED, false));
+            clock.set(Duration.ofSeconds(2).toNanos());
+            listener.onPotionEffect(new EntityPotionEffectEvent(player, strong, weak, null,
+                    EntityPotionEffectEvent.Cause.PLUGIN, EntityPotionEffectEvent.Action.CHANGED, false));
+            clock.set(Duration.ofSeconds(3).toNanos());
+            listener.onPotionEffect(new EntityPotionEffectEvent(player, strong, null, null,
+                    EntityPotionEffectEvent.Cause.EXPIRATION, EntityPotionEffectEvent.Action.REMOVED, false));
+            states.save().get(3, TimeUnit.SECONDS);
+            assertEquals(2000, states.snapshot().eyeProgress(id).accumulatedMillis(),
+                    "a rejected plugin replacement must not interrupt the effective drunk potion");
+        }
+    }
+
+    @Test
+    void effectiveDirectDrinkAccumulatesAcrossRefreshAndDurablyUnlocksAtEightHours() throws Exception {
+        UUID id = UUID.randomUUID();
+        var player = mock(Player.class);
+        when(player.getUniqueId()).thenReturn(id);
+        var clock = new AtomicLong();
+        var repository = new YamlStealthStateRepository(directory.resolve("state.yml"));
+        try (var states = new StealthStateManager(repository, repository.load())) {
+            var progression = new EyeProgressionService(states, clock::get, ignored -> { });
+            var listener = new EyePotionListener(progression, failure -> fail(failure));
+            var nightVision = new PotionEffect(PotionEffectType.NIGHT_VISION, 9600, 0);
+            listener.onPotionEffect(new EntityPotionEffectEvent(player, null, nightVision, player,
+                    EntityPotionEffectEvent.Cause.POTION_DRINK, EntityPotionEffectEvent.Action.ADDED, true));
+            for (int refresh = 1; refresh < 60; refresh++) {
+                clock.set(Duration.ofSeconds(refresh * 480L).toNanos());
+                listener.onPotionEffect(new EntityPotionEffectEvent(player, new PotionEffect(PotionEffectType.NIGHT_VISION, 1, 0), nightVision, player,
+                        EntityPotionEffectEvent.Cause.POTION_DRINK, EntityPotionEffectEvent.Action.CHANGED, true));
+            }
+            clock.set(Duration.ofHours(8).toNanos() - 1_000_000);
+            progression.checkpoint(id).get(3, TimeUnit.SECONDS);
+            assertFalse(progression.isUnlocked(id));
+            clock.addAndGet(1_000_000);
+            listener.onPotionEffect(new EntityPotionEffectEvent(player, nightVision, null, null,
+                    EntityPotionEffectEvent.Cause.EXPIRATION, EntityPotionEffectEvent.Action.REMOVED, false));
+            states.save().get(3, TimeUnit.SECONDS);
+            assertTrue(progression.isUnlocked(id), "eight hours of effective drink events must unlock the Eye");
+            assertEquals(28_800_000, repository.load().eyeProgress(id).accumulatedMillis());
+            assertTrue(progression.activePlayerIds().isEmpty());
+        }
+    }
+}

src/nativeTest/java/games/dmg/spigotstealth/NativeRuntime.java

@@ -0,0 +1,61 @@
+package games.dmg.spigotstealth;
+
+import java.util.List;
+import java.util.stream.Stream;
+import net.minecraft.SharedConstants;
+import net.minecraft.commands.Commands;
+import net.minecraft.core.HolderLookup;
+import net.minecraft.core.LayeredRegistryAccess;
+import net.minecraft.core.Registry;
+import net.minecraft.core.RegistryAccess;
+import net.minecraft.resources.Identifier;
+import net.minecraft.resources.RegistryDataLoader;
+import net.minecraft.server.Bootstrap;
+import net.minecraft.server.MinecraftServer;
+import net.minecraft.server.RegistryLayer;
+import net.minecraft.server.ReloadableServerResources;
+import net.minecraft.server.packs.PackType;
+import net.minecraft.server.packs.repository.ServerPacksSource;
+import net.minecraft.server.packs.resources.MultiPackResourceManager;
+import net.minecraft.server.permissions.LevelBasedPermissionSet;
+import net.minecraft.tags.TagLoader;
+import net.minecraft.util.Util;
+import net.minecraft.world.flag.FeatureFlags;
+import net.minecraft.world.level.DataPackConfig;
+import net.minecraft.world.level.WorldDataConfiguration;
+import org.bukkit.craftbukkit.CraftRegistry;
+
+/** Loads vanilla registries/tags/components using the same path as the server's own tests. */
+final class NativeRuntime {
+    private NativeRuntime() {}
+    private static boolean ready;
+
+    static synchronized void bootstrap() throws Exception {
+        if (ready) { return; }
+        SharedConstants.tryDetectVersion();
+        Bootstrap.bootStrap();
+        var flags = FeatureFlags.VANILLA_SET;
+        var packs = ServerPacksSource.createVanillaTrustedRepository();
+        MinecraftServer.configurePackRepository(packs, new WorldDataConfiguration(new DataPackConfig(
+                FeatureFlags.REGISTRY.toNames(flags).stream().map(Identifier::getPath).toList(), List.of()), flags), true, false);
+        try (var resources = new MultiPackResourceManager(PackType.SERVER_DATA, packs.openAllSelected())) {
+            LayeredRegistryAccess<RegistryLayer> layers = RegistryLayer.createRegistryAccess();
+            List<Registry.PendingTags<?>> tags = TagLoader.loadTagsForExistingRegistries(resources, layers.getLayer(RegistryLayer.STATIC));
+            List<HolderLookup.RegistryLookup<?>> lookups = TagLoader.buildUpdatedLookups(layers.getAccessForLoading(RegistryLayer.WORLDGEN), tags);
+            RegistryAccess.Frozen worldgen = RegistryDataLoader.load(resources, lookups,
+                    RegistryDataLoader.WORLDGEN_REGISTRIES, Util.backgroundExecutor()).join();
+            layers = layers.replaceFrom(RegistryLayer.WORLDGEN, worldgen);
+            RegistryAccess.Frozen dimensions = RegistryDataLoader.load(resources,
+                    Stream.concat(lookups.stream(), worldgen.listRegistries()).toList(),
+                    RegistryDataLoader.DIMENSION_REGISTRIES, Util.backgroundExecutor()).join();
+            layers = layers.replaceFrom(RegistryLayer.DIMENSIONS, dimensions);
+            Class.forName(org.bukkit.Registry.class.getName());
+            var datapack = ReloadableServerResources.loadResources(resources, layers, tags, flags,
+                    Commands.CommandSelection.DEDICATED, LevelBasedPermissionSet.ALL_PERMISSIONS,
+                    Util.backgroundExecutor(), Runnable::run).join();
+            datapack.updateComponentsAndStaticRegistryTags();
+            CraftRegistry.setMinecraftRegistry(layers.compositeAccess().freeze());
+        }
+        ready = true;
+    }
+}