Handling AVPs where the payload is empty about go-diameter

[fiorix]

Is this an AVP you're getting off the wire or an AVP you're generating?
If it's from the network please provide me with a pcap to take a look. Otherwise you should provide the empty payload, which is an interface and currently cannot be nil. We could definitely talk about adding checks to all data types but that might cost performance.

[taseppa]

I'm getting this off wire. I would be happy to provide pcap but the AVPs contain some potentially sensitive information I can't share.

[fiorix]

So you're saying the parser crash when a FailedAVP is received, containing the failed AVP with empty data? I can't reproduce that.

[jaroszan]

@taseppa: may be you can provide which failed AVP you are receiving and code for the parser? Some relevant text extract from pcap without sensitive information?

[taseppa]

It should happen with every AVP that is of type unsigned32. If you check unsigned32.go:17

return Unsigned32(binary.BigEndian.Uint32(b)), nil

This will panic if byte array is empty http://play.golang.org/p/6ctpKdZ0H0

[fiorix]

This patch should fix it, let me know otherwise.

[fiorix]

At some point we might want to do some more strict checks in all these decoder functions to ensure the data is the exact length we want. If zero (the case of embedded in FailedAVP) we return default value, if exact length we decode, other than that we return error.

[taseppa]

This patch looks good, thanks!