ByteString.ToArray throws sometimes

[Aaronontheweb]

Version: Akka.NET v1.3.2

This error is not stable, but here it is:

[ERROR][11/2/2017 3:03:37 PM][Thread 0018][[akka://demo/user/StatsD-%5BUdp-%3E127.0.0.1%3A8125%5D0/StreamSupervisor-12/Flow-0-0-unknown-operation#737196236]] Error in stage [UdpSink]: Provided index is outside the bounds of the buffer to copy to.
Parameter name: index
Cause: System.ArgumentOutOfRangeException: Provided index is outside the bounds of the buffer to copy to.
Parameter name: index
   at Akka.IO.ByteString.CopyTo(Byte[] buffer, Int32 index, Int32 count)
   at Phobos.Monitoring.StatsD.Streams.UdpSink.UdpSinkLogic.SendToSocket(ByteString bytes)
   at Akka.Streams.Implementation.Fusing.GraphInterpreter.Execute(Int32 eventLimit)

The ByteString was created via a ByteString.FromString operation earlier.

[Horusiath]

This will be hard to detect actually. Maybe use FsCheck to test ByteString.CopyTo? A longer solution is to build ByteString as a proper rope struct.

[Aaronontheweb]

I think an FsCheck spec is a good way to go here.

[Horusiath]

@Aaronontheweb is this actually an issue or can we close it?

[Aaronontheweb]

I think we still need to keep it open for a bit, but it doesn't need to be part of the 1.3.3 milestone any longer.

[vasily-kirichenko]

I think the bug is not in ByteString, but in the calling code, which passes wrong combination of buffer and index:

akka.net/src/core/Akka/Util/ByteString.cs

Line 487 in 952154e

if (index < 0 || index >= buffer.Length) throw new ArgumentOutOfRangeException(nameof(index), "Provided index is outside the bounds of the buffer to copy to.");

[Aaronontheweb]

@vasily-kirichenko I'll double check the code that threw it, but AFAIK I wasn't calling that method you linked directly. I was calling some of the higher level ByteString.FromString methods, which is where I think the bug might be.