From a993a08b8d1dbc57a283338f1617382470944376 Mon Sep 17 00:00:00 2001
From: Nassim Jahnke <nassim@njahnke.dev>
Date: Sat, 24 Aug 2024 18:00:06 +0200
Subject: [PATCH] Only map between different primitive types when explicitly
 requested This would otherwise only happen with unsafe type usage

---
 .../api/protocol/packet/PacketWrapper.java      | 12 ++++++++++++
 .../api/protocol/remapper/PacketHandlers.java   |  4 ++--
 .../protocol/packet/PacketWrapperImpl.java      | 17 +++++++++++++----
 3 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/api/src/main/java/com/viaversion/viaversion/api/protocol/packet/PacketWrapper.java b/api/src/main/java/com/viaversion/viaversion/api/protocol/packet/PacketWrapper.java
index 4ca573a0c..8cfdf07fb 100644
--- a/api/src/main/java/com/viaversion/viaversion/api/protocol/packet/PacketWrapper.java
+++ b/api/src/main/java/com/viaversion/viaversion/api/protocol/packet/PacketWrapper.java
@@ -145,6 +145,18 @@ public interface PacketWrapper {
      */
     <T> T passthrough(Type<T> type) throws InformativeException;
 
+    /**
+     * Take a value from the input and write to the output, mapping the output type.
+     * This only works for types implementing {@link com.viaversion.viaversion.api.type.TypeConverter}, which is generally only the primitive wrapper types.
+     *
+     * @param type       The type to read.
+     * @param mappedType The type to write.
+     * @param <T>        The return type of the type you wish to pass through.
+     * @return The type which was read/written.
+     * @throws InformativeException If it failed to read or write
+     */
+    <T> T passthroughAndMap(Type<?> type, Type<T> mappedType) throws InformativeException;
+
     /**
      * Take all the inputs and write them to the output.
      *
diff --git a/api/src/main/java/com/viaversion/viaversion/api/protocol/remapper/PacketHandlers.java b/api/src/main/java/com/viaversion/viaversion/api/protocol/remapper/PacketHandlers.java
index 73b21c222..8b9d16cea 100644
--- a/api/src/main/java/com/viaversion/viaversion/api/protocol/remapper/PacketHandlers.java
+++ b/api/src/main/java/com/viaversion/viaversion/api/protocol/remapper/PacketHandlers.java
@@ -63,8 +63,8 @@ public abstract class PacketHandlers implements PacketHandler {
      * @param oldType old type
      * @param newType new type
      */
-    public void map(Type oldType, Type newType) {
-        handler(wrapper -> wrapper.write(newType, wrapper.read(oldType)));
+    public void map(Type<?> oldType, Type<?> newType) {
+        handler(wrapper -> wrapper.passthroughAndMap(oldType, newType));
     }
 
     /**
diff --git a/common/src/main/java/com/viaversion/viaversion/protocol/packet/PacketWrapperImpl.java b/common/src/main/java/com/viaversion/viaversion/protocol/packet/PacketWrapperImpl.java
index 92ad9561a..269d21fa0 100644
--- a/common/src/main/java/com/viaversion/viaversion/protocol/packet/PacketWrapperImpl.java
+++ b/common/src/main/java/com/viaversion/viaversion/protocol/packet/PacketWrapperImpl.java
@@ -123,7 +123,7 @@ public class PacketWrapperImpl implements PacketWrapper {
                 continue;
             }
             if (currentIndex == index) {
-                packetValue.setValue(attemptTransform(type, value));
+                packetValue.setValue(value);
                 return;
             }
             currentIndex++;
@@ -160,7 +160,7 @@ public class PacketWrapperImpl implements PacketWrapper {
 
     @Override
     public <T> void write(Type<T> type, T value) {
-        packetValues.add(new PacketValue<>(type, attemptTransform(type, value)));
+        packetValues.add(new PacketValue<>(type, value));
     }
 
     /**
@@ -170,7 +170,7 @@ public class PacketWrapperImpl implements PacketWrapper {
      * @param value        value
      * @return value if already matching, else the converted value or possibly unmatched value
      */
-    private <T> @Nullable T attemptTransform(Type<T> expectedType, @Nullable T value) {
+    private <T> @Nullable T attemptTransform(Type<T> expectedType, @Nullable Object value) {
         if (value != null && !expectedType.getOutputClass().isAssignableFrom(value.getClass())) {
             // Attempt conversion
             if (expectedType instanceof TypeConverter<?>) {
@@ -180,7 +180,8 @@ public class PacketWrapperImpl implements PacketWrapper {
 
             Via.getPlatform().getLogger().warning("Possible type mismatch: " + value.getClass().getName() + " -> " + expectedType.getOutputClass());
         }
-        return value;
+        //noinspection unchecked
+        return (T) value;
     }
 
     @Override
@@ -196,6 +197,14 @@ public class PacketWrapperImpl implements PacketWrapper {
         }
     }
 
+    @Override
+    public <T> T passthroughAndMap(Type<?> type, Type<T> mappedType) throws InformativeException {
+        final Object value = read(type);
+        final T mappedValue = attemptTransform(mappedType, value);
+        write(mappedType, mappedValue);
+        return mappedValue;
+    }
+
     @Override
     public void passthroughAll() throws InformativeException {
         // Copy previous objects