NetworkTables freeze bugs across C++/Java/Python
 

Some of you may remember this bug from last year that affected C++ teams. If you look at this year's NetworkTables code... pretty sure it's still there, somehow the patch slipped through.

I really like the idea of NetworkTables, and SmartDashboard/SFX are super useful -- so I spent a week examining the python NetworkTables implementation. I've identified at least two other places (though, I'm sure there's more) where deadlock/increased latency is possible -- and these places are the same across all three languages. I've written some details on this github issue.

pynetworktables has fixes for these bugs, and should be pretty stable as of 2015.1.0.

I am not planning on fixing the other platforms, as I've already spent enough of my life fixing networktables bugs :( But hopefully this information can help someone else fix it.

Re: NetworkTables freeze bugs across C++/Java/Python
 

Ive noticed that NetworkTables for a long time has been really clunky. I was assuming most of that was caused by limitations of the CRIO platform. Maybe now that we have a much more capable system, it might be time to rewrite it to be cleaner and safer. I have had to help many teams debug issues with network tables, usually caused by teams writing data too quickly and causing the buffers to lag out.

I'm not much of a network programmer, so I don't know how much help I would actually be, but I would be glad to help try and learn more about how to make network tables cleaner. Being over 50 files in Java just to have a data sharing protocol seems like a lot too much.

Re: NetworkTables freeze bugs across C++/Java/Python
 

It has nothing to do with the platform, language or design. The implementation is just a little shaky - as if the authors were well-meaning but not so well-versed in network and multi-tasking environments. Perhaps a program where veteran software mentors server as code reviewers would help?

Re: NetworkTables freeze bugs across C++/Java/Python
 

By all three languages, you are talking about Java, C++, and python, right?

I do not think these issues exist in the LV implementation, but checking to see if that was what you were meaning by all three.

Greg McKaskle

Re: NetworkTables freeze bugs across C++/Java/Python
 

Yes, thanks for clarifying. I have not looked at the LV implementation.