The phrase "robust discussion" means having a strong and lively conversation or debate where different ideas and opinions are shared openly and thoroughly. Full definition
There have been some, shall we say, robust discussions of these issues, see here, here, here here, and especially here and here. (blog.politics.ox.ac.uk)
He's coming here to have what he hopes is a very robust discussion about the economy. (nystateofpolitics.com)
Our participants have a lot to contribute, and we have learned how important it is to leave plenty of time for robust discussion and comment. (rch.org.au)