Error for feeds with no item about tidyrss

[RobertMyles]

Looking at this again, @chainsawriot , I think feeds like this are either uncommon or shouldn't be the target of parsing, so I don't want to customise tidyRSS to handle something like this.

[chainsawriot]

@RobertMyles Fine.

For this project, we check around 1000 RSS every few hours and around 10% of them are having this error. So, feeds like this are actually not that uncommon at least in our application. It's an edge case for sure. But I think it would be better to tell users this is an edge case. Those are valid feeds; if the "contract" in the documentation is hold, it should return an empty tibble / list.

tidyRSS/R/tidyfeed.R

Lines 18 to 20 in 1a4c5fc

	#' @description \code{tidyfeed()} downloads and parses rss feeds. The function
	#' produces either a tidy data frame or a named list, easy to use for further
	#' manipulation and analysis.

Even if no tibble is gonna returned, a more informative error message (e.g. "No parsable item in this feed") is helpful even when it raises an error.

If you want that, I can submit a PR.

[RobertMyles]

Sure, I hadn't realised feeds like this are that common, did really seem like an edge case to me and I'm reluctant to try and adapt the package to all the messed-up feeds that can be found in the wild (I tried that before). Happy to receive a PR if you'd like to do that, I may not get around to doing this myself for a while.