Support changes introduced in a recent BungeeCord commit

bungee/build.gradle.kts

@@ -1,4 +1,4 @@
-var bungeeCommit = "ff5727c"
+var bungeeCommit = "dfd847f"
 var gsonVersion = "2.8.0"
 var guavaVersion = "21.0"
 

bungee/src/main/java/org/geysermc/floodgate/inject/bungee/BungeeInjector.java

@@ -35,6 +35,7 @@ import lombok.Getter;
 import lombok.RequiredArgsConstructor;
 import net.md_5.bungee.netty.PipelineUtils;
 import net.md_5.bungee.protocol.MinecraftEncoder;
+import net.md_5.bungee.protocol.Varint21LengthFieldExtraBufPrepender;
 import net.md_5.bungee.protocol.Varint21LengthFieldPrepender;
 import org.geysermc.floodgate.api.logger.FloodgateLogger;
 import org.geysermc.floodgate.inject.CommonPlatformInjector;
@@ -52,6 +53,16 @@ public final class BungeeInjector extends CommonPlatformInjector {
     public void inject() {
         // Can everyone just switch to Velocity please :)
 
+        // Newer Bungee versions have a separate prepender for backend and client connections
+        Field serverFramePrepender =
+                ReflectionUtils.getField(PipelineUtils.class, "serverFramePrepender");
+        if (serverFramePrepender != null) {
+            BungeeCustomServerPrepender customServerPrepender = new BungeeCustomServerPrepender(
+                    this, ReflectionUtils.castedStaticValue(serverFramePrepender)
+            );
+            BungeeReflectionUtils.setFieldValue(null, serverFramePrepender, customServerPrepender);
+        }
+
         Field framePrepender = ReflectionUtils.getField(PipelineUtils.class, "framePrepender");
 
         // Required in order to inject into both Geyser <-> proxy AND proxy <-> server
@@ -119,6 +130,22 @@ public final class BungeeInjector extends CommonPlatformInjector {
         }
     }
 
+    @RequiredArgsConstructor
+    private static final class BungeeCustomServerPrepender
+            extends Varint21LengthFieldExtraBufPrepender {
+        private final BungeeInjector injector;
+        private final Varint21LengthFieldExtraBufPrepender original;
+
+        @Override
+        public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
+            original.handlerAdded(ctx);
+            // The Minecraft encoder being in the pipeline isn't present until later
+
+            // Proxy <-> Server
+            ctx.pipeline().addLast(BUNGEE_INIT, new BungeeProxyToServerInjectInitializer(injector));
+        }
+    }
+
     @RequiredArgsConstructor
     private static final class BungeeClientToProxyInjectInitializer
             extends ChannelInboundHandlerAdapter {