Fix command suggestion leak (#6592)

Co-authored-by: Jason Penilla <11360596+jpenilla@users.noreply.github.com>

patches/server/0833-Check-requirement-before-suggesting-root-nodes.patch

@@ -0,0 +1,31 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: stonar96 <minecraft.stonar96@gmail.com>
+Date: Sun, 12 Sep 2021 00:14:21 +0200
+Subject: [PATCH] Check requirement before suggesting root nodes
+
+Child nodes are handled by CommandDispatcher#parse checking
+requirements.
+
+Vanilla clients only send ServerboundCommandSuggestionPacket when
+encountering a command node with ASK_SERVER suggestions, however a
+modified client can send this packet whenever it wants.
+
+diff --git a/src/main/java/com/mojang/brigadier/CommandDispatcher.java b/src/main/java/com/mojang/brigadier/CommandDispatcher.java
+index ca24830bac1a04b798229d1946863429c7849495..5584040fe48c18aa809f5a1510157e735851df79 100644
+--- a/src/main/java/com/mojang/brigadier/CommandDispatcher.java
++++ b/src/main/java/com/mojang/brigadier/CommandDispatcher.java
+@@ -594,10 +594,14 @@ public class CommandDispatcher<S> {
+         int i = 0;
+         for (final CommandNode<S> node : parent.getChildren()) {
+             CompletableFuture<Suggestions> future = Suggestions.empty();
++            // Paper start - Don't suggest if the requirement isn't met
++            if (parent != this.root || node.canUse(context.getSource())) {
+             try {
+                 future = node.listSuggestions(context.build(truncatedInput), new SuggestionsBuilder(truncatedInput, truncatedInputLowerCase, start));
+             } catch (final CommandSyntaxException ignored) {
+             }
++            }
++            // Paper end
+             futures[i++] = future;
+         }
+ 

patches/server/0834-Don-t-respond-to-ServerboundCommandSuggestionPacket-.patch

@@ -0,0 +1,23 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: stonar96 <minecraft.stonar96@gmail.com>
+Date: Sun, 12 Sep 2021 00:14:21 +0200
+Subject: [PATCH] Don't respond to ServerboundCommandSuggestionPacket when
+ tab-complete is disabled
+
+
+diff --git a/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java b/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
+index 5d7c47b0a302f7db95a0b2bb811c5656c6b02beb..7bf03b78a26b6a697a8d10e8832703421f96b2bb 100644
+--- a/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
++++ b/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
+@@ -796,6 +796,11 @@ public class ServerGamePacketListenerImpl implements ServerPlayerConnection, Ser
+         }
+         // Paper end
+         // CraftBukkit end
++        // Paper start - Don't suggest if tab-complete is disabled
++        if (org.spigotmc.SpigotConfig.tabComplete < 0) {
++            return;
++        }
++        // Paper end
+         StringReader stringreader = new StringReader(packet.getCommand());
+ 
+         if (stringreader.canRead() && stringreader.peek() == '/') {