[R-pkg-devel] Usage of internet resources in examples

[Andy Teucher]

Our package bcdata (https://cran.r-project.org/package=bcdata) retrieves public data from British Columbia data services, so the examples are dependent on successfully hitting web resources. When we initially submitted to CRAN the examples were wrapped in \dontrun{}, but we were asked to change them to use \donttest{}.

 
Now, CRAN is running checks with _R_CHECK_DONTTEST_EXAMPLES_=true, and one of the examples has failed due to a changed web resource. I got an email asking me to fix it and reminding me of the CRAN policy:
 

  'Packages which use Internet resources should fail gracefully with an informative message

 if the resource is not available or has changed (and not give a check warning nor error).'

  This needs correction whether or not the resource recovers.

 
I would prefer that in normal use, the function calling the internet resources fails with an error so that the user is properly alerted. I also agree that these failures shouldn't cause a check error. To demonstrate the use of these functions in examples, is there a preferred method of ensuring that failures will not cause a check warning or error? Should I try to revert back to using \dontrun{} and plead my case? Wrap in `if interactive())`?
 

Thanks very much,

Andy Teucher