Ensure old Paper builds can still use ping passthrough

bootstrap/spigot/src/main/java/org/geysermc/geyser/platform/spigot/GeyserPaperPingPassthrough.java

@@ -35,6 +35,7 @@ import org.geysermc.geyser.ping.IGeyserPingPassthrough;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
+import java.lang.reflect.Constructor;
 import java.net.InetSocketAddress;
 
 /**
@@ -42,6 +43,8 @@ import java.net.InetSocketAddress;
  * applied.
  */
 public final class GeyserPaperPingPassthrough implements IGeyserPingPassthrough {
+    private static final Constructor<PaperServerListPingEvent> OLD_CONSTRUCTOR = ReflectedNames.getOldPaperPingConstructor();
+
     private final GeyserSpigotLogger logger;
 
     public GeyserPaperPingPassthrough(GeyserSpigotLogger logger) {
@@ -54,9 +57,17 @@ public final class GeyserPaperPingPassthrough implements IGeyserPingPassthrough
         try {
             // We'd rather *not* use deprecations here, but unfortunately any Adventure class would be relocated at
             // runtime because we still have to shade in our own Adventure class. For now.
-            PaperServerListPingEvent event = new PaperServerListPingEvent(new GeyserStatusClient(inetSocketAddress),
-                    Bukkit.getMotd(), Bukkit.shouldSendChatPreviews(), Bukkit.getOnlinePlayers().size(),
-                    Bukkit.getMaxPlayers(), Bukkit.getVersion(), MinecraftProtocol.getJavaProtocolVersion(), null);
+            PaperServerListPingEvent event;
+            if (OLD_CONSTRUCTOR != null) {
+                // Approximately pre-1.19
+                event = OLD_CONSTRUCTOR.newInstance(new GeyserStatusClient(inetSocketAddress),
+                        Bukkit.getMotd(), Bukkit.getOnlinePlayers().size(),
+                        Bukkit.getMaxPlayers(), Bukkit.getVersion(), MinecraftProtocol.getJavaProtocolVersion(), null);
+            } else {
+                event = new PaperServerListPingEvent(new GeyserStatusClient(inetSocketAddress),
+                        Bukkit.getMotd(), Bukkit.shouldSendChatPreviews(), Bukkit.getOnlinePlayers().size(),
+                        Bukkit.getMaxPlayers(), Bukkit.getVersion(), MinecraftProtocol.getJavaProtocolVersion(), null);
+            }
             Bukkit.getPluginManager().callEvent(event);
             if (event.isCancelled()) {
                 // We have to send a ping, so not really sure what else to do here.

bootstrap/spigot/src/main/java/org/geysermc/geyser/platform/spigot/GeyserSpigotPlugin.java

@@ -167,14 +167,16 @@ public class GeyserSpigotPlugin extends JavaPlugin implements GeyserBootstrap {
         if (geyserConfig.isLegacyPingPassthrough()) {
             this.geyserSpigotPingPassthrough = GeyserLegacyPingPassthrough.init(geyser);
         } else {
-            try {
-                Class.forName("com.destroystokyo.paper.event.server.PaperServerListPingEvent");
+            if (ReflectedNames.checkPaperPingEvent()) {
                 this.geyserSpigotPingPassthrough = new GeyserPaperPingPassthrough(geyserLogger);
-            } catch (ClassNotFoundException e) {
+            } else if (ReflectedNames.newSpigotPingConstructorExists()) {
                 this.geyserSpigotPingPassthrough = new GeyserSpigotPingPassthrough(geyserLogger);
+            } else {
+                // Can't enable one of the other options
+                this.geyserSpigotPingPassthrough = GeyserLegacyPingPassthrough.init(geyser);
             }
         }
-        geyserLogger.debug("Spigot ping passthrough type: " + (this.geyserSpigotPingPassthrough == null ? null : this.geyserSpigotPingPassthrough.getClass()));
+        geyserLogger.info("Spigot ping passthrough type: " + (this.geyserSpigotPingPassthrough == null ? null : this.geyserSpigotPingPassthrough.getClass()));
 
         this.geyserCommandManager = new GeyserSpigotCommandManager(geyser);
 

bootstrap/spigot/src/main/java/org/geysermc/geyser/platform/spigot/ReflectedNames.java

@@ -0,0 +1,90 @@
+/*
+ * Copyright (c) 2019-2022 GeyserMC. http://geysermc.org
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * @author GeyserMC
+ * @link https://github.com/GeyserMC/Geyser
+ */
+
+package org.geysermc.geyser.platform.spigot;
+
+import com.destroystokyo.paper.event.server.PaperServerListPingEvent;
+import com.destroystokyo.paper.network.StatusClient;
+import org.bukkit.event.server.ServerListPingEvent;
+import org.bukkit.util.CachedServerIcon;
+
+import javax.annotation.Nullable;
+import java.lang.reflect.Constructor;
+import java.net.InetAddress;
+
+/**
+ * A utility class for checking on the existence of classes, constructors, fields, methods
+ */
+public final class ReflectedNames {
+
+    static boolean checkPaperPingEvent() {
+        return classExists("com.destroystokyo.paper.event.server.PaperServerListPingEvent");
+    }
+
+    /**
+     * @return if this class name exists
+     */
+    private static boolean classExists(String clazz) {
+        try {
+            Class.forName(clazz);
+            return true;
+        } catch (ClassNotFoundException e) {
+            return false;
+        }
+    }
+
+    static boolean newSpigotPingConstructorExists() {
+        return getConstructor(ServerListPingEvent.class, InetAddress.class, String.class, boolean.class, int.class, int.class) != null;
+    }
+
+    static Constructor<PaperServerListPingEvent> getOldPaperPingConstructor() {
+        if (getConstructor(PaperServerListPingEvent.class, StatusClient.class, String.class, boolean.class, int.class,
+                int.class, String.class, int.class, CachedServerIcon.class) != null) {
+            // @NotNull StatusClient client, @NotNull String motd, boolean shouldSendChatPreviews, int numPlayers, int maxPlayers,
+            //            @NotNull String version, int protocolVersion, @Nullable CachedServerIcon favicon
+            // New constructor is present
+            return null;
+        }
+        // @NotNull StatusClient client, @NotNull String motd, int numPlayers, int maxPlayers,
+        //            @NotNull String version, int protocolVersion, @Nullable CachedServerIcon favicon
+        return getConstructor(PaperServerListPingEvent.class, StatusClient.class, String.class, int.class, int.class,
+                String.class, int.class, CachedServerIcon.class);
+    }
+
+    /**
+     * @return if this class has a constructor with the specified arguments
+     */
+    @Nullable
+    private static <T> Constructor<T> getConstructor(Class<T> clazz, Class<?>... args) {
+        try {
+            return clazz.getConstructor(args);
+        } catch (NoSuchMethodException e) {
+            return null;
+        }
+    }
+
+    private ReflectedNames() {
+    }
+}