New event: BrigadierSuggestionsEvent to have more control on 1.13+ suggestions

api/src/main/java/net/md_5/bungee/api/event/BrigadierSuggestionsEvent.java

@@ -0,0 +1,40 @@
+package net.md_5.bungee.api.event;
+
+import com.mojang.brigadier.suggestion.Suggestions;
+import lombok.Data;
+import lombok.EqualsAndHashCode;
+import lombok.ToString;
+import net.md_5.bungee.api.connection.Connection;
+import net.md_5.bungee.api.plugin.Cancellable;
+
+/**
+ * Event called when an 1.13+ player uses tab completion.
+ * This event is fired after {@link TabCompleteEvent}.
+ */
+@Data
+@ToString(callSuper = true)
+@EqualsAndHashCode(callSuper = true)
+public class BrigadierSuggestionsEvent extends TargetedEvent implements Cancellable
+{
+
+    /**
+     * Cancelled state.
+     */
+    private boolean cancelled;
+    /**
+     * The message the player has already entered.
+     */
+    private final String cursor;
+    /**
+     * The suggestions that will be sent to the client. If this list is empty,
+     * the request will be forwarded to the server.
+     */
+    private Suggestions suggestions;
+
+    public BrigadierSuggestionsEvent(Connection sender, Connection receiver, String cursor, Suggestions suggestions)
+    {
+        super( sender, receiver );
+        this.cursor = cursor;
+        this.suggestions = suggestions;
+    }
+}

api/src/main/java/net/md_5/bungee/api/event/TabCompleteEvent.java

@@ -9,6 +9,8 @@ import net.md_5.bungee.api.plugin.Cancellable;
 
 /**
  * Event called when a player uses tab completion.
+ * For 1.13+ clients, you can also use {@link BrigadierSuggestionsEvent} for
+ * more control of the suggestions.
  */
 @Data
 @ToString(callSuper = true)

proxy/src/main/java/net/md_5/bungee/connection/UpstreamBridge.java

@@ -6,7 +6,6 @@ import com.mojang.brigadier.suggestion.Suggestion;
 import com.mojang.brigadier.suggestion.Suggestions;
 import io.netty.channel.Channel;
 import java.util.ArrayList;
-import java.util.LinkedList;
 import java.util.List;
 import net.md_5.bungee.BungeeCord;
 import net.md_5.bungee.ServerConnection.KeepAliveData;
@@ -14,6 +13,7 @@ import net.md_5.bungee.UserConnection;
 import net.md_5.bungee.Util;
 import net.md_5.bungee.api.ProxyServer;
 import net.md_5.bungee.api.connection.ProxiedPlayer;
+import net.md_5.bungee.api.event.BrigadierSuggestionsEvent;
 import net.md_5.bungee.api.event.ChatEvent;
 import net.md_5.bungee.api.event.PlayerDisconnectEvent;
 import net.md_5.bungee.api.event.PluginMessageEvent;
@@ -172,35 +172,49 @@ public class UpstreamBridge extends PacketHandler
         TabCompleteEvent tabCompleteEvent = new TabCompleteEvent( con, con.getServer(), tabComplete.getCursor(), suggestions );
         bungee.getPluginManager().callEvent( tabCompleteEvent );
 
+        List<String> legacyResults = tabCompleteEvent.getSuggestions();
+
+        if ( con.getPendingConnection().getVersion() < ProtocolConstants.MINECRAFT_1_13 )
+        {
             if ( tabCompleteEvent.isCancelled() )
             {
                 throw CancelSendSignal.INSTANCE;
             }
 
-        List<String> results = tabCompleteEvent.getSuggestions();
+            if ( !legacyResults.isEmpty() )
-        if ( !results.isEmpty() )
             {
-            // Unclear how to handle 1.13 commands at this point. Because we don't inject into the command packets we are unlikely to get this far unless
+                con.unsafe().sendPacket( new TabCompleteResponse( legacyResults ) );
-            // Bungee plugins are adding results for commands they don't own anyway
+                throw CancelSendSignal.INSTANCE;
-            if ( con.getPendingConnection().getVersion() < ProtocolConstants.MINECRAFT_1_13 )
+            }
-            {
-                con.unsafe().sendPacket( new TabCompleteResponse( results ) );
         } else
         {
             int start = tabComplete.getCursor().lastIndexOf( ' ' ) + 1;
             int end = tabComplete.getCursor().length();
-                StringRange range = StringRange.between( start, end );
+            StringRange lastArgumentRange = StringRange.between( start, end );
 
-                List<Suggestion> brigadier = new LinkedList<>();
+            List<Suggestion> brigadier = new ArrayList<>( legacyResults.size() );
-                for ( String s : results )
+            for ( String s : legacyResults )
             {
-                    brigadier.add( new Suggestion( range, s ) );
+                brigadier.add( new Suggestion( lastArgumentRange, s ) );
             }
 
-                con.unsafe().sendPacket( new TabCompleteResponse( tabComplete.getTransactionId(), new Suggestions( range, brigadier ) ) );
+            BrigadierSuggestionsEvent tabCompleteRequestEvent = new BrigadierSuggestionsEvent( con, con.getServer(), tabComplete.getCursor(), new Suggestions( lastArgumentRange, brigadier ) );
-            }
+            tabCompleteRequestEvent.setCancelled( tabCompleteEvent.isCancelled() );
+            bungee.getPluginManager().callEvent( tabCompleteRequestEvent );
+
+            if ( tabCompleteRequestEvent.isCancelled() )
+            {
                 throw CancelSendSignal.INSTANCE;
             }
+
+            Suggestions brigadierResults = tabCompleteRequestEvent.getSuggestions();
+
+            if ( !brigadierResults.isEmpty() )
+            {
+                con.unsafe().sendPacket( new TabCompleteResponse( tabComplete.getTransactionId(), brigadierResults ) );
+                throw CancelSendSignal.INSTANCE;
+            }
+        }
     }
 
     @Override