Release runtime statics

- Null Iris.instance, the console sender, the Multiverse link, the compat set and the chunk tickets at the end of teardownRuntime
- Bind the host bridge suppliers to the constructing plugin instead of reading the instance static on every call
- State that Iris is disabled when service, getTemp or getSender is reached after teardown instead of raising a bare NullPointerException
- Add IrisRuntimeStatics so a disable drops the service registry, both capability singletons, the loaded datapack runtime and the localization roots
- Add WorldLifecycleService.reset and WorldRuntimeControlService.reset so the next boot snapshots the server it is running on
- Add ServerConfigurator.resetLoadedDatapackRuntime so an enable revalidates instead of trusting the previous boot's fingerprint
- Clear the localization data folder and plain-text memo on shutdown
- Add BukkitPlatform.releaseHost and call it last in terminal cleanup so the disabled plugin, console sender and log bridge stop being reachable from a static

adapters/bukkit/plugin/src/main/java/art/arcane/iris/Iris.java

@@ -39,6 +39,7 @@ import art.arcane.iris.core.SettingsHotloadWatch;
 import art.arcane.iris.core.ServerConfigurator;
 import art.arcane.iris.core.datapack.DatapackIngestService;
 import art.arcane.iris.core.datapack.DatapackIngestService.StartupValidationOutcome;
+import art.arcane.iris.core.lifecycle.IrisRuntimeStatics;
 import art.arcane.iris.core.lifecycle.ManagedWorldLoader;
 import art.arcane.iris.core.lifecycle.MissingWorldStorageLog;
 import art.arcane.iris.core.lifecycle.PaperLibBootstrap;
@@ -216,16 +217,23 @@ public class Iris extends VolmitPlugin implements Listener, ReloadAware {
     private volatile ServerShutdownBoundary serverShutdownBoundary;
 
     public static VolmitSender getSender() {
-        if (sender == null) {
-            sender = new VolmitSender(Bukkit.getConsoleSender());
-            sender.setTag(instance.getTag());
+        VolmitSender current = sender;
+        if (current == null) {
+            Iris plugin = instance;
+            current = new VolmitSender(Bukkit.getConsoleSender());
+            current.setTag(plugin == null ? IrisSafeguard.mode().tag("") : plugin.getTag());
+            sender = current;
         }
-        return sender;
+        return current;
     }
 
     @SuppressWarnings("unchecked")
     public static <T> T service(Class<T> c) {
-        return (T) instance.services.get(c);
+        Iris plugin = instance;
+        if (plugin == null || plugin.services == null) {
+            throw new IllegalStateException("Iris is disabled; " + c.getSimpleName() + " is unavailable");
+        }
+        return (T) plugin.services.get(c);
     }
 
     public static void callEvent(Event e) {
@@ -264,7 +272,11 @@ public class Iris extends VolmitPlugin implements Listener, ReloadAware {
     }
 
     public static File getTemp() {
-        return instance.getDataFolder("cache", "temp");
+        Iris plugin = instance;
+        if (plugin == null) {
+            throw new IllegalStateException("Iris is disabled; the temp folder is unavailable");
+        }
+        return plugin.getDataFolder("cache", "temp");
     }
 
     public static void msg(String string) {
@@ -543,11 +555,11 @@ public class Iris extends VolmitPlugin implements Listener, ReloadAware {
                 Iris::msg,
                 Iris::reportError,
                 (event) -> Iris.callEvent((org.bukkit.event.Event) event),
-                () -> Iris.instance.getDataFolder(),
-                (path) -> Iris.instance.getDataFile(path),
-                () -> Iris.instance.getJarFile(),
-                () -> Iris.instance.getIrisVersion(),
-                () -> Iris.instance.getMCVersion()));
+                this::getDataFolder,
+                this::getDataFile,
+                this::getJarFile,
+                this::getIrisVersion,
+                this::getMCVersion));
         SlimJar.load();
     }
 
@@ -1055,10 +1067,24 @@ public class Iris extends VolmitPlugin implements Listener, ReloadAware {
                 Iris.reportError("Failed to close Iris I/O workers.", failure);
             }
             clearQueues();
-            IrisServices.clear();
+            IrisRuntimeStatics.reset();
+            releaseStatics();
         }
     }
 
+    /**
+     * A disabled plugin must not stay reachable through a static. Everything that reads these either runs
+     * while Iris is enabled or already handles their absence; the platform binding outlives them because
+     * core still logs through it until finishTerminalCleanup unbinds it.
+     */
+    private static void releaseStatics() {
+        linkMultiverseCore = null;
+        compat = null;
+        tickets = null;
+        sender = null;
+        instance = null;
+    }
+
     private void quiesceRuntimeForServerShutdown(String reason) {
         serverStopTeardownDeferred.set(true);
         INMS.get().deferPluginClassLoaderClose();
@@ -1201,6 +1227,7 @@ public class Iris extends VolmitPlugin implements Listener, ReloadAware {
                     failure.printStackTrace(SHUTDOWN_ERRORS);
                 }
             }
+            BukkitPlatform.releaseHost();
         }
     }
 
@@ -1395,7 +1422,7 @@ public class Iris extends VolmitPlugin implements Listener, ReloadAware {
     }
 
     public int getIrisVersion() {
-        String input = Iris.instance.getDescription().getVersion();
+        String input = getDescription().getVersion();
         int hyphenIndex = input.indexOf('-');
         if (hyphenIndex != -1) {
             String result = input.substring(0, hyphenIndex);

core/src/main/java/art/arcane/iris/core/ServerConfigurator.java

@@ -158,6 +158,20 @@ public class ServerConfigurator {
         }
     }
 
+    /**
+     * Forgets what the previous boot loaded, so an enable in the same JVM recompiles and revalidates rather
+     * than trusting a fingerprint taken against a server that is gone.
+     */
+    public static void resetLoadedDatapackRuntime() {
+        synchronized (DATAPACK_INSTALL_LOCK) {
+            loadedDatapackRuntimeReady = false;
+            loadedDatapackCompilerInputFingerprint = "";
+            loadedDatapackRegistryRequirements = Map.of();
+            loadedDatapackRuntimeGeneration++;
+            loadedDatapackRestartRequired = false;
+        }
+    }
+
     public static LoadedDatapackRuntimeInvalidation invalidateLoadedDatapackRuntime() {
         synchronized (DATAPACK_INSTALL_LOCK) {
             boolean wasReady = loadedDatapackRuntimeReady;

core/src/main/java/art/arcane/iris/core/lifecycle/IrisRuntimeStatics.java

@@ -0,0 +1,28 @@
+package art.arcane.iris.core.lifecycle;
+
+import art.arcane.iris.core.ServerConfigurator;
+import art.arcane.iris.core.localization.IrisLanguage;
+import art.arcane.iris.core.runtime.WorldRuntimeControlService;
+import art.arcane.iris.spi.IrisServices;
+
+/**
+ * Drops every process-wide cache core keeps about the running server, so a disable leaves nothing an
+ * enable in the same JVM could answer from.
+ * <p>
+ * The capability singletons are the reason this exists: each holds reflective handles onto the live
+ * CraftServer and MinecraftServer, and a boot that reused them would be talking to the previous server's
+ * objects. The platform binding itself is not cleared here - core still logs through it while the adapter
+ * finishes its own teardown - and is unbound last by the adapter.
+ */
+public final class IrisRuntimeStatics {
+    private IrisRuntimeStatics() {
+    }
+
+    public static void reset() {
+        IrisServices.clear();
+        WorldLifecycleService.reset();
+        WorldRuntimeControlService.reset();
+        ServerConfigurator.resetLoadedDatapackRuntime();
+        IrisLanguage.shutdown();
+    }
+}

core/src/main/java/art/arcane/iris/core/lifecycle/WorldLifecycleService.java

@@ -51,6 +51,15 @@ public final class WorldLifecycleService {
         this.worldBackendByKey = new ConcurrentHashMap<>();
     }
 
+    /**
+     * Drops the cached snapshot so the next boot in this JVM builds one against the server it is running on.
+     */
+    public static void reset() {
+        synchronized (WorldLifecycleService.class) {
+            instance = null;
+        }
+    }
+
     public static WorldLifecycleService get() {
         WorldLifecycleService current = instance;
         if (current != null) {

core/src/main/java/art/arcane/iris/core/localization/IrisLanguage.java

@@ -429,6 +429,8 @@ public final class IrisLanguage {
     }
 
     public static synchronized void shutdown() {
+        dataFolder = null;
+        PLAIN_MEMO.set(null);
         PluginLanguageService current = selections;
         selections = null;
         if (current != null) {

core/src/main/java/art/arcane/iris/core/runtime/WorldRuntimeControlService.java

@@ -76,6 +76,15 @@ public final class WorldRuntimeControlService {
                 + ", " + backend.describeCapabilities();
     }
 
+    /**
+     * Drops the cached snapshot so the next boot in this JVM builds one against the server it is running on.
+     */
+    public static void reset() {
+        synchronized (WorldRuntimeControlService.class) {
+            instance = null;
+        }
+    }
+
     public static WorldRuntimeControlService get() {
         WorldRuntimeControlService current = instance;
         if (current != null) {

core/src/main/java/art/arcane/iris/engine/decorator/DecoratorCore.java

@@ -50,6 +50,7 @@ final class DecoratorCore {
 
     static final ThreadLocal<PlaceOpts> SCRATCH_OPTS = ThreadLocal.withInitial(PlaceOpts::new);
 
+
     static final class PlaceOpts {
         boolean caveSkipFluid;
         boolean underwater;

core/src/main/java/art/arcane/iris/platform/bukkit/BukkitPlatform.java

@@ -103,6 +103,19 @@ public final class BukkitPlatform implements IrisPlatform {
         PLUGIN = plugin;
     }
 
+    /**
+     * Drops every reference this class holds to the disabled plugin. Called last in the adapter's teardown,
+     * after core has stopped logging through the host bridge, so a disabled plugin instance is not reachable
+     * from a static for the life of the JVM.
+     */
+    public static void releaseHost() {
+        PLUGIN = null;
+        HUD_BAR = null;
+        HUD_LANES = null;
+        CONSOLE = null;
+        BRIDGE = null;
+    }
+
     public static Plugin plugin() {
         Plugin plugin = PLUGIN;
         if (plugin == null) {

core/src/test/java/art/arcane/iris/core/lifecycle/IrisRuntimeStaticsTest.java

@@ -0,0 +1,51 @@
+package art.arcane.iris.core.lifecycle;
+
+import art.arcane.iris.core.runtime.WorldRuntimeControlService;
+import art.arcane.iris.spi.IrisServices;
+import art.arcane.iris.testsupport.BukkitTestServer;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+import static org.junit.Assert.assertNotSame;
+import static org.junit.Assert.assertNull;
+
+/**
+ * Iris keeps process-wide caches that describe the running server: the service registry, and the lifecycle
+ * and runtime-control singletons that each hold a capability snapshot of reflective handles onto the live
+ * server. Nothing cleared them on disable, so a re-enable in the same JVM kept answering from the previous
+ * boot's snapshot.
+ */
+public class IrisRuntimeStaticsTest {
+    @Before
+    public void installServer() {
+        BukkitTestServer.install();
+    }
+
+    @After
+    public void clearStatics() {
+        IrisRuntimeStatics.reset();
+    }
+
+    @Test
+    public void resetUnbindsEveryRegisteredService() {
+        Runnable service = () -> {
+        };
+        IrisServices.register(Runnable.class, service);
+
+        IrisRuntimeStatics.reset();
+
+        assertNull(IrisServices.getOrNull(Runnable.class));
+    }
+
+    @Test
+    public void resetDropsTheCachedCapabilitySingletons() {
+        WorldLifecycleService lifecycle = WorldLifecycleService.get();
+        WorldRuntimeControlService control = WorldRuntimeControlService.get();
+
+        IrisRuntimeStatics.reset();
+
+        assertNotSame(lifecycle, WorldLifecycleService.get());
+        assertNotSame(control, WorldRuntimeControlService.get());
+    }
+}

core/src/test/java/art/arcane/iris/platform/bukkit/BukkitPlatformHostReleaseTest.java

@@ -0,0 +1,30 @@
+package art.arcane.iris.platform.bukkit;
+
+import org.bukkit.plugin.Plugin;
+import org.junit.After;
+import org.junit.Test;
+
+import static org.junit.Assert.assertFalse;
+import static org.mockito.Mockito.mock;
+
+/**
+ * The host statics are how core reaches the plugin. Nothing cleared them on disable, so the disabled
+ * plugin instance, its console sender and its log bridge stayed reachable from a static for the life of
+ * the JVM.
+ */
+public class BukkitPlatformHostReleaseTest {
+    @After
+    public void clearHost() {
+        BukkitPlatform.releaseHost();
+    }
+
+    @Test
+    public void releasingTheHostDropsThePluginAndTheHud() {
+        BukkitPlatform.hostPlugin(mock(Plugin.class));
+
+        BukkitPlatform.releaseHost();
+
+        assertFalse(BukkitPlatform.hasPlugin());
+        assertFalse(BukkitPlatform.hasHud());
+    }
+}