When using binary data over WebSockets we trigger the require statement in the inflate method of the MessageInflater. This happens with release 5.0.0-alpha.12 and 5.0.0.alpha.14. We are using OKhttp on Android.

This only seems to happen with a certain Package size and composition. We attached the packet we used to replicate this a 100% of the time. This is the package before it is being deflated. We can reproduce this issue with multiple server setups. If we return the package below on a server that understands per message deflate we will get the Exception every time:

bytestream.txt

The failure is always that the inflate method is called but deflatedBytes.size is > 0. Since it is a require call that it must be 0 we fail here.

We assume that the actual issue is on the inflate before the actual failure as this is apparently "finished" while still leaving 4 bytes in the stream.

The last inflate call in WebSocketReader before we trigger the require condition

Before the last readOrInflate call before we trigger the require condition.

In the last call of readOrInflateBefore we trigger the require condition.

The end of the last inflate call before we trigger the require condition. Note that deflatedBytes size is 4 here which is the size we will trigger the require condition with.

We haven not been able to pin down the why this happens exactly, but we can we can reproduce this a 100% of the time so we can easily provide further information if needed.