Scissors/patches/server/0038-Reject-translatable-components-with-more-than-32-pla.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: VideoGameSmash12 <videogamesm12@gmail.com>
Date: Thu, 16 Mar 2023 01:42:08 -0500
Subject: [PATCH] Reject translatable components with more than 32 placeholders


diff --git a/src/main/java/net/minecraft/network/chat/Component.java b/src/main/java/net/minecraft/network/chat/Component.java
index 3c0ee4e1f42f6056ca86a6f9f129d467e29a2fbc..534f1e6092d2b64b6e6e3182eac0cc38718ab2f8 100644
--- a/src/main/java/net/minecraft/network/chat/Component.java
+++ b/src/main/java/net/minecraft/network/chat/Component.java
@@ -26,6 +26,7 @@ import java.util.List;
 import java.util.Map.Entry;
 import java.util.Optional;
 import javax.annotation.Nullable;
+
 import net.minecraft.ChatFormatting;
 import net.minecraft.Util;
 import net.minecraft.network.chat.contents.BlockDataSource;
@@ -44,6 +45,9 @@ import net.minecraft.util.GsonHelper;
 import net.minecraft.util.LowerCaseEnumTypeAdapterFactory;
 // CraftBukkit start
 import com.google.common.collect.Streams;
+
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 import java.util.stream.Stream;
 // CraftBukkit end
 
@@ -255,6 +259,58 @@ public interface Component extends Message, FormattedText, Iterable<Component> {
             }
         });
 
+        private static final Pattern PLACEHOLDER_PATTERN = Pattern.compile("%[0-9]{1,}\\$s");
+
+        // Scissors start - Calculate number of placeholders in translatable components before serializing them
+        private long calculatePlaceholderCount(JsonElement element)
+        {
+            long amount = 0;
+
+            if (!element.isJsonObject())
+            {
+                return amount;
+            }
+
+            JsonObject from = element.getAsJsonObject();
+
+            // Figure out how many placeholders are in a single translatable component
+            if (from.has("translate") && from.get("translate").isJsonPrimitive())
+            {
+                String key = GsonHelper.getAsString(from, "translate");
+                Matcher matcher = PLACEHOLDER_PATTERN.matcher(key);
+                amount += matcher.results().count();
+
+                // Recursively figure out how many placeholders the component has in the "with" shit
+                if (from.has("with") && from.get("with").isJsonArray())
+                {
+                    JsonArray array = GsonHelper.getAsJsonArray(from, "with");
+
+                    for (JsonElement within : array)
+                    {
+                        long amountWithin = calculatePlaceholderCount(within);
+
+                        if (amountWithin == 1)
+                        {
+                            amount++;
+                        }
+                        else if (amountWithin > 1)
+                        {
+                            amount = amount * amountWithin;
+                        }
+                    }
+                }
+            }
+            // Also applies to keybind components, but to a lesser extent
+            else if (from.has("keybind") && from.get("keybind").isJsonPrimitive())
+            {
+                String key = GsonHelper.getAsString(from, "keybind");
+                Matcher matcher = PLACEHOLDER_PATTERN.matcher(key);
+                amount += matcher.results().count();
+            }
+            return amount;
+        }
+        // Scissors end
+
         public Serializer() {}
 
         public MutableComponent deserialize(JsonElement jsonelement, Type type, JsonDeserializationContext jsondeserializationcontext) throws JsonParseException {
@@ -287,6 +343,14 @@ public interface Component extends Message, FormattedText, Iterable<Component> {
                     }
                 } else {
                     JsonObject jsonobject = jsonelement.getAsJsonObject();
+
+                    // Scissors start - Reject translatable components with more than 32 placeholders in them
+                    if (calculatePlaceholderCount(jsonobject) > 32)
+                    {
+                        return Component.empty().append("*** Component has too many placeholders ***").withStyle(ChatFormatting.RED);
+                    }
+                    // Scissors end
+
                     String s;
 
                     if (jsonobject.has("text")) {