Improve exception handling

api/src/main/java/com/viaversion/viaversion/api/protocol/AbstractProtocol.java

@@ -334,8 +334,9 @@ public abstract class AbstractProtocol<C1 extends ClientboundPacketType, C2 exte
     }
 
     private void throwRemapError(Direction direction, State state, int oldId, int newId, InformativeException e) throws InformativeException {
-        // Don't print errors during handshake
+        // Don't print errors during handshake/login/status
-        if (state == State.HANDSHAKE) {
+        if (state != State.PLAY && direction == Direction.SERVERBOUND && !Via.getManager().debugHandler().enabled()) {
+            e.setShouldBePrinted(false);
             throw e;
         }
 
@@ -369,6 +370,7 @@ public abstract class AbstractProtocol<C1 extends ClientboundPacketType, C2 exte
 
     @Override
     public @Nullable <T> T get(Class<T> objectClass) {
+        //noinspection unchecked
         return (T) storedObjects.get(objectClass);
     }
 

api/src/main/java/com/viaversion/viaversion/exception/InformativeException.java

@@ -27,6 +27,7 @@ import java.util.Map;
 
 public class InformativeException extends Exception {
     private final Map<String, Object> info = new HashMap<>();
+    private boolean shouldBePrinted = true;
     private int sources;
 
     public InformativeException(Throwable cause) {
@@ -46,6 +47,14 @@ public class InformativeException extends Exception {
         return sourceClazz.isAnonymousClass() ? sourceClazz.getName() + " (Anonymous)" : sourceClazz.getName();
     }
 
+    public boolean shouldBePrinted() {
+        return shouldBePrinted;
+    }
+
+    public void setShouldBePrinted(final boolean shouldBePrinted) {
+        this.shouldBePrinted = shouldBePrinted;
+    }
+
     @Override
     public String getMessage() {
         StringBuilder builder = new StringBuilder("Please report this on the Via support Discord or open an issue on the relevant GitHub repository\n");

api/src/main/java/com/viaversion/viaversion/util/PipelineUtil.java

@@ -28,6 +28,7 @@ import io.netty.channel.ChannelPipeline;
 import io.netty.handler.codec.ByteToMessageDecoder;
 import io.netty.handler.codec.MessageToByteEncoder;
 import io.netty.handler.codec.MessageToMessageDecoder;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
@@ -116,6 +117,25 @@ public final class PipelineUtil {
         return false;
     }
 
+    /**
+     * Check if a stack trace contains a certain exception and returns it if present.
+     *
+     * @param t throwable
+     * @param c the exception to look for
+     * @return contained exception of t if present
+     */
+    public static <T> @Nullable T getCause(Throwable t, Class<T> c) {
+        while (t != null) {
+            if (c.isAssignableFrom(t.getClass())) {
+                //noinspection unchecked
+                return (T) t;
+            }
+
+            t = t.getCause();
+        }
+        return null;
+    }
+
     /**
      * Get the context for a the channel handler before a certain name.
      *

bukkit/src/main/java/com/viaversion/viaversion/bukkit/handlers/BukkitDecodeHandler.java

@@ -17,9 +17,7 @@
  */
 package com.viaversion.viaversion.bukkit.handlers;
 
-import com.viaversion.viaversion.api.Via;
 import com.viaversion.viaversion.api.connection.UserConnection;
-import com.viaversion.viaversion.api.protocol.packet.State;
 import com.viaversion.viaversion.bukkit.util.NMSUtil;
 import com.viaversion.viaversion.exception.CancelCodecException;
 import com.viaversion.viaversion.exception.CancelDecoderException;
@@ -67,9 +65,15 @@ public final class BukkitDecodeHandler extends MessageToMessageDecoder<ByteBuf>
         }
 
         super.exceptionCaught(ctx, cause);
-        if (!NMSUtil.isDebugPropertySet() && PipelineUtil.containsCause(cause, InformativeException.class)
+        if (NMSUtil.isDebugPropertySet()) {
-                && (connection.getProtocolInfo().getState() != State.HANDSHAKE || Via.getManager().isDebug())) {
+            return;
-            cause.printStackTrace(); // Print if CB doesn't already do it
+        }
+
+        // Print if CB doesn't already do it
+        final InformativeException exception = PipelineUtil.getCause(cause, InformativeException.class);
+        if (exception != null && exception.shouldBePrinted()) {
+            cause.printStackTrace();
+            exception.setShouldBePrinted(false);
         }
     }
 

bukkit/src/main/java/com/viaversion/viaversion/bukkit/handlers/BukkitEncodeHandler.java

@@ -17,9 +17,7 @@
  */
 package com.viaversion.viaversion.bukkit.handlers;
 
-import com.viaversion.viaversion.api.Via;
 import com.viaversion.viaversion.api.connection.UserConnection;
-import com.viaversion.viaversion.api.protocol.packet.State;
 import com.viaversion.viaversion.bukkit.util.NMSUtil;
 import com.viaversion.viaversion.exception.CancelCodecException;
 import com.viaversion.viaversion.exception.CancelEncoderException;
@@ -110,9 +108,15 @@ public final class BukkitEncodeHandler extends MessageToMessageEncoder<ByteBuf>
         }
 
         super.exceptionCaught(ctx, cause);
-        if (!NMSUtil.isDebugPropertySet() && PipelineUtil.containsCause(cause, InformativeException.class)
+        if (NMSUtil.isDebugPropertySet()) {
-                && (connection.getProtocolInfo().getState() != State.HANDSHAKE || Via.getManager().isDebug())) {
+            return;
-            cause.printStackTrace(); // Print if CB doesn't already do it
+        }
+
+        // Print if CB doesn't already do it
+        final InformativeException exception = PipelineUtil.getCause(cause, InformativeException.class);
+        if (exception != null && exception.shouldBePrinted()) {
+            cause.printStackTrace();
+            exception.setShouldBePrinted(false);
         }
     }
 

common/src/main/java/com/viaversion/viaversion/protocol/packet/PacketWrapperImpl.java

@@ -49,7 +49,9 @@ public class PacketWrapperImpl implements PacketWrapper {
     private final ByteBuf inputBuffer;
     private final UserConnection userConnection;
     private boolean send = true;
-    /** Only non-null if specifically set and gotten before packet transformation */
+    /**
+     * Only non-null if specifically set and gotten before packet transformation
+     */
     private PacketType packetType;
     private int id;
     private final Deque<Pair<Type, Object>> readableObjects = new ArrayDeque<>();
@@ -78,9 +80,7 @@ public class PacketWrapperImpl implements PacketWrapper {
             }
             currentIndex++;
         }
-
+        throw createInformativeException(new ArrayIndexOutOfBoundsException("Could not find type " + type.getTypeName() + " at " + index), type, index);
-        Exception e = new ArrayIndexOutOfBoundsException("Could not find type " + type.getTypeName() + " at " + index);
-        throw new InformativeException(e).set("Type", type.getTypeName()).set("Index", index).set("Packet ID", getId()).set("Packet Type", packetType).set("Data", packetValues);
     }
 
     @Override
@@ -121,20 +121,22 @@ public class PacketWrapperImpl implements PacketWrapper {
             }
             currentIndex++;
         }
-        Exception e = new ArrayIndexOutOfBoundsException("Could not find type " + type.getTypeName() + " at " + index);
+        throw createInformativeException(new ArrayIndexOutOfBoundsException("Could not find type " + type.getTypeName() + " at " + index), type, index);
-        throw new InformativeException(e).set("Type", type.getTypeName()).set("Index", index).set("Packet ID", getId()).set("Packet Type", packetType);
     }
 
     @Override
     public <T> T read(Type<T> type) throws Exception {
-        if (type == Type.NOTHING) return null;
+        if (type == Type.NOTHING) {
+            return null;
+        }
+
         if (readableObjects.isEmpty()) {
             Preconditions.checkNotNull(inputBuffer, "This packet does not have an input buffer.");
             // We could in the future log input read values, but honestly for things like bulk maps, mem waste D:
             try {
                 return type.read(inputBuffer);
             } catch (Exception e) {
-                throw new InformativeException(e).set("Type", type.getTypeName()).set("Packet ID", getId()).set("Packet Type", packetType).set("Data", packetValues);
+                throw createInformativeException(e, type, packetValues.size() + 1);
             }
         }
 
@@ -147,8 +149,7 @@ public class PacketWrapperImpl implements PacketWrapper {
         } else if (rtype == Type.NOTHING) {
             return read(type); // retry
         } else {
-            Exception e = new IOException("Unable to read type " + type.getTypeName() + ", found " + read.key().getTypeName());
+            throw createInformativeException(new IOException("Unable to read type " + type.getTypeName() + ", found " + read.key().getTypeName()), type, readableObjects.size());
-            throw new InformativeException(e).set("Type", type.getTypeName()).set("Packet ID", getId()).set("Packet Type", packetType).set("Data", packetValues);
         }
     }
 
@@ -209,13 +210,22 @@ public class PacketWrapperImpl implements PacketWrapper {
             try {
                 packetValue.key().write(buffer, packetValue.value());
             } catch (Exception e) {
-                throw new InformativeException(e).set("Index", index).set("Type", packetValue.key().getTypeName()).set("Packet ID", getId()).set("Packet Type", packetType).set("Data", packetValues);
+                throw createInformativeException(e, packetValue.key(), index);
             }
             index++;
         }
         writeRemaining(buffer);
     }
 
+    private InformativeException createInformativeException(final Exception cause, final Type<?> type, final int index) {
+        return new InformativeException(cause)
+                .set("Index", index)
+                .set("Type", type.getTypeName())
+                .set("Packet ID", this.id)
+                .set("Packet Type", this.packetType)
+                .set("Data", this.packetValues);
+    }
+
     @Override
     public void clearInputBuffer() {
         if (inputBuffer != null) {