fix: auto-patch legacy Citizens EmptyChannel metadata for Netty 4.1 compatibility

WindSpigot-Server/pom.xml

@@ -155,13 +155,17 @@
             <version>3.21.0</version>
         </dependency>
 
-		<!-- Kyori api -->
-		<!-- https://mvnrepository.com/artifact/net.kyori/adventure-api -->
-        <dependency>
-            <groupId>net.kyori</groupId>
-            <artifactId>adventure-key</artifactId>
-            <version>4.10.1</version>
-        </dependency>
+		<dependency>
+			<groupId>net.kyori</groupId>
+			<artifactId>adventure-key</artifactId>
+			<version>4.10.1</version>
+		</dependency>
+
+		<dependency>
+			<groupId>org.javassist</groupId>
+			<artifactId>javassist</artifactId>
+			<version>3.29.2-GA</version>
+		</dependency>
 	</dependencies>
 
 	<repositories>

WindSpigot-Server/src/main/java/com/windpvp/windspigot/commons/PluginUtils.java

@@ -1,13 +1,28 @@
 package com.windpvp.windspigot.commons;
+
 import org.bukkit.plugin.Plugin;
 
-/**
- * @author Elierrr
- */
 public class PluginUtils {
+
     public static int getCitizensBuild(Plugin plugin) {
+        if (plugin == null || plugin.getDescription() == null) {
+            return 2396;
+        }
+        return parseCitizensBuild(plugin.getDescription().getVersion());
+    }
+
+    public static int parseCitizensBuild(String version) {
         try {
-            return Integer.parseInt(plugin.getDescription().getVersion().split("\\(build ")[1].replace(")", ""));
+            if (version == null) {
+                return 2396;
+            }
+            if (version.contains("(build ")) {
+                return Integer.parseInt(version.split("\\(build ")[1].replace(")", "").trim());
+            }
+            if (version.startsWith("2.0.25") || version.startsWith("2.0.26") || version.startsWith("2.0.27")) {
+                return 1000;
+            }
+            return 2396;
         } catch (Throwable ignored) {
             return 2396;
         }

WindSpigot-Server/src/main/java/org/bukkit/craftbukkit/CraftServer.java

@@ -169,6 +169,10 @@
 import net.minecraft.server.WorldSettings;
 import net.minecraft.server.WorldType;
 import xyz.sculas.nacho.malware.AntiMalware;
+import javassist.ClassPool;
+import javassist.CtClass;
+import javassist.CtMethod;
+import javassist.LoaderClassPath;
 
 public final class CraftServer implements Server {
 	private static final Player[] EMPTY_PLAYER_ARRAY = new Player[0];
@@ -371,19 +375,30 @@ public void loadPlugins() {
 					}
 					// Nacho end
 
-					// Nacho start - Add notice for older Citizens versions
+					// WindSpigot start - GamingOP69 - Auto-patch older Citizens EmptyChannel for Netty 4.1 compatibility
 					else if (plugin.getDescription().getFullName().contains("Citizens")) {
 						if (PluginUtils.getCitizensBuild(plugin) < 2396) {
-							logger.warning("Please update to Citizens 2.0.28 #7 or higher!\n"
-									+ "Previously, there was a fix for older versions, but that has been removed.\n"
-									+ "So, if you want Citizens to work, please update!\n"
-									+ "You can download the latest version with this link: "
-									+ "https://ci.citizensnpcs.co/job/Citizens2/\n"
-									+ "Sleeping for 10s so this message can be read.");
-							Thread.sleep(10000);
+							try {
+								ClassPool pool = ClassPool.getDefault();
+								pool.insertClassPath(new LoaderClassPath(plugin.getClass().getClassLoader()));
+								pool.importPackage("io.netty.channel.ChannelMetadata");
+
+								CtClass emptyChannel = pool.get("net.citizensnpcs.nms.v1_8_R3.network.EmptyChannel");
+								if (emptyChannel.isFrozen()) {
+									emptyChannel.defrost();
+								}
+
+								CtMethod metaData = emptyChannel.getDeclaredMethods("metadata")[0];
+								metaData.setBody("{ return new ChannelMetadata(true); }");
+
+								emptyChannel.toClass(plugin.getClass().getClassLoader(), plugin.getClass().getProtectionDomain());
+								logger.info("Successfully patched Citizens EmptyChannel for Netty 4.1 compatibility!");
+							} catch (Throwable t) {
+								logger.warning("Could not automatically patch Citizens: " + t.getMessage());
+							}
 						}
 					}
-					// Nacho end
+					// WindSpigot end - GamingOP69
 
 					plugin.getLogger().info(String.format("Loading %s", plugin.getDescription().getFullName()));
 					plugin.onLoad();

WindSpigot-Server/src/test/java/com/windpvp/windspigot/citizens/CitizensVersionDetectionTest.java

@@ -0,0 +1,38 @@
+package com.windpvp.windspigot.citizens;
+
+import com.windpvp.windspigot.commons.PluginUtils;
+import org.junit.Assert;
+import org.junit.Test;
+
+public class CitizensVersionDetectionTest {
+
+    @Test
+    public void testOlderBuildDetected() {
+        int build = PluginUtils.parseCitizensBuild("2.0.25-SNAPSHOT (build 1770)");
+        Assert.assertEquals(1770, build);
+        Assert.assertTrue("Older build 1770 must be less than 2396", build < 2396);
+    }
+
+    @Test
+    public void testLegacyVersionWithoutBuildDetected() {
+        int build25 = PluginUtils.parseCitizensBuild("2.0.25");
+        Assert.assertTrue("2.0.25 must trigger older build detection", build25 < 2396);
+
+        int build26 = PluginUtils.parseCitizensBuild("2.0.26-SNAPSHOT");
+        Assert.assertTrue("2.0.26 must trigger older build detection", build26 < 2396);
+    }
+
+    @Test
+    public void testNewerBuildDetected() {
+        int build = PluginUtils.parseCitizensBuild("2.0.28-SNAPSHOT (build 2400)");
+        Assert.assertEquals(2400, build);
+        Assert.assertTrue("Newer build 2400 must be >= 2396", build >= 2396);
+    }
+
+    @Test
+    public void testFallbackOnNullOrUnknownVersion() {
+        Assert.assertEquals(2396, PluginUtils.parseCitizensBuild(null));
+        Assert.assertEquals(2396, PluginUtils.parseCitizensBuild("unknown-version"));
+        Assert.assertEquals(2396, PluginUtils.getCitizensBuild(null));
+    }
+}