CatServer/patches/net/minecraft/network/NettyPacketEncoder.java.patch

--- ../src-base/minecraft/net/minecraft/network/NettyPacketEncoder.java
+++ ../src-work/minecraft/net/minecraft/network/NettyPacketEncoder.java
@@ -37,6 +37,13 @@
                 LOGGER.debug(RECEIVED_PACKET_MARKER, "OUT: [{}:{}] {}", p_encode_1_.channel().attr(NetworkManager.PROTOCOL_ATTRIBUTE_KEY).get(), integer, p_encode_2_.getClass().getName());
             }
 
+            // CatServer start - Forge set the state is PLAY, but the LOGIN packet hasn't encoded.
+            if (integer == null && (integer = EnumConnectionState.LOGIN.getPacketId(this.direction, p_encode_2_)) != null)
+            {
+                LOGGER.debug("Current state is {}, but send packet {}", enumconnectionstate, p_encode_2_.getClass().getSimpleName());
+            }
+            // CatServer end
+
             if (integer == null)
             {
                 throw new IOException("Can't serialize unregistered packet");
@@ -52,7 +59,7 @@
                 }
                 catch (Throwable throwable)
                 {
-                    LOGGER.error(throwable);
+                    throw throwable; // Forge: throw this instead of logging it, to prevent corrupt packets from being sent to the client where they are much harder to debug.
                 }
             }
         }