After trying to export my WooCommerce shopping feed to Google Shopping, I had numerous problems with the extensions currently out there.
I’m not sure they work with older versions of wordpress (like 3.5), or if it was because I had over 30k products in the feed, which is why I had all the errors. I also couldn’t get product variations to work properly, and had to manually edit the feed at first which takes a really long time because of all the products!
But after trying the fixes incorporated in the Feedonomics WooCommerce API showing how to export WooCommerce article, everything seemed to be working fine.