My widget requests server data updates in getTimeline to refresh information. But if the server API returns an error and I don't execute the completion callback, will this cause any problems?
widget gettimeline completion question
Doesn't the completion handler have to be called within the method? (as in, does Code force you to return something from the method?) If not, it should be fine because it just doesn't mark that you've got new data; it didn't complete.
If your widget doesn't receive any updates, it should be written to handle missing data.
As an example, add the Apple Weather widget to your Home Screen. Turn off your Wi-Fi, mobile data etc. and see what it looks like. It says it can get data right now.
Your widget should handle no data in a similar way.